Sunday, January 31, 2016

 

Simple. Neat. Really No Trouble at All: Stellarium


Do you like pretty planetarium programs? Computer programs that put a beautiful depiction of the night sky on your PC's display? I know I do. Sure, a planetarium doesn’t have to be pretty to be useful. Heck, I did a lot with good, old Sky Travel, and even in the 8-bit Commodore-64 days it was hardly cutting edge as far as graphics.  But pretty is nice. Pretty and useful is even better. And pretty and cheap is best of all as far as I am concerned.

As I wrote the other day, when it comes to astronomy software, planetarium programs anyway, what I’ve used most in recent years is that oldie-but-goodie TheSky 6 Professional from Software Bisque. It’s a great soft that does everything except brew the coffee at dawn when your observing run is done. There is only one problem with it:  it’s getting old. It has long since been obsoleted by Bisque’s current TheSky, TheSky X.

In most respects, TheSky 6’s obsolescence doesn’t make much difference. Bisque worked hard to add features and squash bugs over the lifetime of the program, so it is pretty bulletproof, does many things, and does most of those many things well. In only one respect does the fact that it is no longer supported cause a problem. I found out what that was the other day when, in a sanguine mood, I decided I’d take a picture of the little morning comet, Catalina.

In order to do that I needed software with current orbital elements for Catalina. With that, I could easily figure out when I should start my astrographic run and when I’d have to end it ahead of the Sun. The program would also allow me to center the telescope on the comet quickly and easily, with just a mouse-click or two. "Well, I’ll just fetch the current orbital elements for Catalina with TheSky 6 and—oh…wait…  Rut-roh."

While I could look up the orbital elements of the visitor and enter them manually into TheSky (if I could figure out where and how to do that), I was not going to be able to have the program automatically download them. Something changed with the URLTheSky uses for retrieving orbital elements for comets and asteroids, and asking the program to do that now results in an error message.

Hmm... So, I could try to get the elements into TheSky manually, or I could just take the quick and easy way out and use another program. My normal choice would have been that old favorite Cartes du Ciel. Unfortunately, as I mentioned last time, it errors-out and crashes on my Toshiba laptop of late. I’d tried various fixes, but nothing had worked, and I wasn’t in the mood to fool with it anymore.

What would I do, then? What would I do? Unfortunately, TheSky and CdC were the only full-featured planetariums currently on my hard drive. I’d have to pick something else. I could have shelled out more than a few bucks to Bisque for TheSky X, which is available for immediate download from their website, but I am cheap, and I was also leery of trying to learn to use X in one afternoon. Then I remembered Stellarium.

Stellarium was program I’d used occasionally over the years, and I’d heard it had been improved greatly since I’d last looked at it, that some of the missing features I wanted were now present, and that more than a few of the rough edges I hadn’t like had been rounded off. Since I didn’t have any other ideas, and Stellarium is free, I figured I had nothing to lose, and downloaded and installed Stellarium 0.14.2.

The program is available for Linux and OSX as well as Windows,  but what I downloaded and what I’ll be talking about here exclusively is the Win version (which requires Open GL graphics), since I wanted to use the PC-only ASCOM telescope drivers with it. Don't have Windows? As I outline below, Stellarium has some built-in scope drivers, so you may be OK.

One thing’s sure:  Stellarium is a pretty program despite its freeware status. Its authors have always endeavored to make their sky look as attractive and realistic as possible, and as soon as I ran the new one, it was obvious that they haven’t stood still in that regard. Stellarium is more striking than ever, from the beautifully hued and toned sky to the lovely horizon landscape. It’s a trip to see the lights of the farmhouse to the northwest come on as darkness falls with the Guéreins horizon landscape selected.

"Pretty" is absolutely worthless if it impacts the usability of a planetarium, however. A little playing around proved that that hasn’t happened with Stellarium. 0.14.2 was just as spritely as ever on my mid-range Toshiba laptop. Grabbing the sky to move it around was as smooth and satisfying as it was many versions ago despite all the additions and improvements to the graphics.

Looked good, yeah, but that wasn’t really what I was concerned about this particular afternoon. My goal was downloading the elements for Catalina, getting the hairy star on my screen, and, first of all, determining when it would be well placed for imaging.

All I had to do to get the current orbital elements into Stellarium was open the configuration window and select “plugins” and “solar system editor.” There I found a button labeled “get orbital elements.” I specified comet elements, and was done. A search then turned up Catalina right where it was supposed to be adjacent to the Dipper’s handle in Ursa Major—I checked an online finder chart to make sure the program had the comet plotted correctly. Well, heck. That was easy enough.

StellariumScope...
A sixty-four dollar question remained, however: As much as I liked Stellarium in the house, would I like it out under the stars connected to a goto telescope? I thought I’d find out. But to do that I’d have to set it up for telescope control.

There are two methods of  connecting the program to a computerized telescope. Easiest, perhaps, is using Stellarium’s built-in scope drivers.  If you have a Meade or Celestron or telescope or a few others that are compatible with those “standards,” the built-in drivers are OK. For details on using them, see my article on Stellarium from five years ago.

But what if your telescope isn’t one supported by the built in drivers? Or you just don’t want to use them for some reason? What if, like me, you want to use the ASCOM universal telescope driver system? StellariumScope has you covered. This add-on makes Stellarium ASCOM compatible just like Cartes du Ciel or any number of other planetariums. That means Stellarium can control almost any telescope mount under the Sun.

Making ASCOM work with Stellarium is fairly easy. You must first download StellariumScope (make sure you get version 2015.12.2.327, which may still be listed as a “beta”) and, if you don’t already have it installed on your computer, the latest ASCOM “platform,” the software that runs ASCOM drivers. Of course you will also want to download (from the ASCOM site, usually) the driver for your particular scope/mount. While the authors of StellariumScope say on their website that their utility was expressly designed to allow Stellarium to work with the EQMOD ASCOM driver, they also say it should work with almost any other scope for which an ASCOM driver is available. I’d be surprised if any run-of-the-mill ASCOM driver gave StellariumScope problems, since EQMOD is far more complex than most.

Once you’ve installed StellariumScope and ASCOM (I’m assuming you’ve got the latest version of Stellarium on your machine), start Stellarium and go to the telescope control configuration section in the plug-ins window, just as described in my earlier article. The only diff is that you choose “External Software or a Remote Computer” rather than specifying that you have a Meade or a Celestron or whatever. That done, close Stellarium.

The first time you run StellariumScope, you will likely be dismayed when it presents you with a bunch of configuration errors. Don’t worry; this is normal and it will tell you how to proceed, giving you instructions for modifying Stellarium’s configuration (usually automatically through StellariumScope). That done, you can set up StellariumScope’s defaults, such as its colors, and whether or not it should automatically start Stellarium when it executes (yes).

Eyepiece view...
The final step is configuring your ASCOM driver. Do that from the main StellariumScope window, by clicking “select mount,” choosing the appropriate telescope driver, and then entering all the required information in ASCOM’s “properties” window. Same old stuff:  com port, lat/lon, tracking mode, etc. That is all there is to it. With the telescope goto aligned and powered up and its serial cable connected to the computer, you can now tick the connect box on the StellariumScope window.

If all is well, Stellarium will connect to your mount (if, like me, you’ve got ASCOM’s little hand control enabled, it should appear). If you move the screen to the object the telescope is currently pointed to, you should see a reticle cursor centered on that object. If you have problems, the help file included with StellariumScope is clear and well-written and should get you out of your mess.

I got StellariumScope working with minimal difficulty, only scratching my head and backtracking once or twice. But just because it was working, that didn’t mean I’d like the way it worked. With Hermione, my 5-inch refractor, on the CGEM and the CGEM aligned and ready to go, I thought I’d give Stellarium its chance to shine.

Frankly, it was all rather anti-climactic. I connected to the mount with StellariumScope, clicked on the magnifying glass in Stellarium’s left icon-bar, searched for the Pacman Nebula, centered it when it was found, held down CTRL and pressed the "1" key, and the CGEM went there, centering the nebula in the frame of my DSLR without a hitch. The only other commands you’ll normally have to mess with are CTRL and 3 (sync) and CTRL and 5 (stop slew). If you don’t like using the CTRL key with a number key, StellariumScope will let you use other keys and  combinations. That’s all there is to it; no fuss no muss. While that is the go-to telescope control story, however, that’s hardly all there is to the new Stellarium.

The Stellarium display is, yes, awful pretty, but what’s even more important is what’s in it. Stellarium is endowed with a useable set of deep sky objects and that set looks to be growing. While it has had the entire NGC/IC for a while, the authors have mentioned recently that the program's deep sky catalogs have been expanded. Unfortunately they haven’t specified in exactly what way. While the DSO screen in the “sky and viewing options” window now allows you to select the PGC and other “beyond the NGC” catalogs, not all of them work. Ticking the PGC box and a couple of other didn’t do a thing, though selecting “LDN” did make dark nebulae appear. I am assuming that the PGC and some of the others are works in progress. At least you don’t have to worry about stars; stars down to magnitude 18 have been available for a while (you download the expanded star catalog with a utility included in the program's configuration section).

DSLR image sensor frame...
What else is new? One thing I don’t remember from years ago is a utility on the bottom icon bar to let you measure distances and position angles between objects. Just click the angle icon, click a starting place on the screen, and, holding down the mouse's left-button, pull out your measuring stick. Worked elegantly and was a big help when I was writing a recent observing article for Sky & Telescope.

While the ability to place objects in eyepiece fields has been around for a while, it’s been improved. You can now add eyepieces with an icon on the top right of the screen without having to mess with the left-side icon bar. When you’ve got all your eyepieces (and telescopes) programmed in, select an object, choose an eyepiece and telescope combo, and you get a great looking eyepiece field view. This top right icon-menu is also where you can set up camera sensor frames for display on the normal chart, allowing you to easily compose your shots. In addition to placing a frame around your object appropriate for your scope/camera, you can easily rotate that frame.

There are quite a few other additions, too, and not just the fairly recent inclusion of comets and asteroids. It’s now easy to find planetary positions with the AstroCalc module. Want to know the when/where/what of upcoming meteor showers? You can now engage a search dialog that will find them for you, give you zenith hourly rates, and find and display the radiant. Mostly, however, Stellarium is much the same as it was when I talked about it five years ago: pretty and good. Well, almost the same; there is one difference. I opined back then that it could not replace Cartes or other “serious” planetariums. That’s not so true anymore. It’s still pretty, but it’s much more capable than it used to be.

After one evening of using Stellarium, I put my credit card back in my wallet. I had been prepared to pay for TheSky X Professional, but suddenly decided I didn’t have to. That is not to say that TheSky X isn’t fantastic or that it doesn’t do a lot more than Stellarium. It just says that for little old me Stellarium is more than enough. It does everything I need a planetarium program to do and then some. And it is continuing to advance. I understand the next release will feature not just a pretty sky background but a photo-realistic one. I can hardly wait.

Oh…how did the comet turn out? It didn’t. Not that night, anyway (I did finally get a snapshot of Catalina a week and a half later). Stellarium could definitely have pointed my scope at the visitor, I was sure…but. By one a.m. clouds were not unexpectedly moving in, and even if they hadn’t been, by that late (for me) hour, my eyes were growing heavy. I did get a nice image of the Pacman Nebula, though, and had found a new astronomy program that I think is going to be my go-to planetarium for a while.

Sunday, January 24, 2016

 

The Refractor Way IV: The Further Adventures…


She's big and she is strong...
If you’re a Face-Front-True-Believer, if you are a regular reader here or you are a Facebook friend of mine, you know I’ve been thinning the herd. Selling telescopes or in some cases just giving them away. There are several reasons for that, but a big one is that I am tired of having scopes that could make someone happy sitting around here rotting unused. Thus far, I’ve got rid of three C8s, a 12.5-inch truss tube Dobsonian, a Criterion RV-6 Dynascope (a six-inch Newtonian, kids), and I am hopeful that I’ve found a home for my StarBlast RFT.

With all those scopes going out, I didn’t feel guilty about letting two new ones come in, a SkyWatcher Pro 120 ED refractor, and a Zhumell 6-inch achromatic refractor. Why refractors? While I still have my Edge 800 C8 and my carbon-fiber-tube C11 (and plan to keep both), at this stage I just find refractors easier. No cool-down to speak of. Easy to image with given their moderate focal lengths and lack of floppy primary mirrors. Super visual images (in good refractors). It’s also true that a hallmark of the last year for me has been change. Needed change. Including in amateur astronomy. So, this week we continue with the further adventures of Ethel (the 6-inch achromat), and Hermione (the 120mm ED APO).

Big Ethel

First up was Ms. Ethel Muggs. Two things were on our agenda, a check of her collimation, which I had noticed was out during first light, and which I had adjusted. I also wanted to see just how bad the chromatic aberration, the color purple that devils the images of achromatic refractors, was. Luckily for me, there was a nice crescent Moon in the sky, and, after Venus maybe, there is nothing in the sky that reveals color correction faux pas in a telescope more quickly.

Once I had the VX mount goto aligned, our first destination was bright Deneb, which was still high enough in the west (barely) to be a usable collimation tool. In went my 4.7mm Explore Scientific eyepiece. “Still out, darnit.” Despite so-so-ish seeing, I could tell the in-focus diffraction rings of the star did not make an unbroken ring around its Airy disk. In truth, I was not surprised. When I’d done the initial collimation I’d been in a hurry and hadn’t gone back and re-checked everything like I should have when I made my final adjustment. Sometimes, tweaking one thing will untweak something else. While the collimation of an f/8 refractor is not overly critical, I wanted to give Ethel her best shot at surviving the Moon Test.

Out came my laser and my Cheshire, which are normally all you need for refractor collimation. When you need to deal with things like objective lens element centering, you’ve got a job for an expert, but basic collimation of a refractor isn’t much more difficult than collimating an SCT. No more difficult at all if Check One is good, actually.

The first thing you check is whether the focuser tailpiece is square-on with regard to the objective lens. The simplest way to do that is by putting a collimation laser (a Newtonian collimation laser) in the focuser (no diagonal) and turning it on. Observe the objective: is the bright red spot of the laser beam centered in the lens? If so, you are golden and can go on to the actual lens collimation. If not, you need to center it before collimating the objective.

How you square the focuser depends on the focuser. Expensive ones like Moonlites will have collimation adjustments. The stock focusers on inexpensive Chinese refractors won’t. But that doesn’t mean they can’t be adjusted. What you do is loosen the screws holding the focuser to the tube. Usually the screw holes are large enough or are slightly elongated enough by design or accident, to allow you to adjust the tilt of the focuser sufficiently to center the laser spot. It doesn’t take much. I did some tip-tapping with a hammer and dowel and soon had that pesky spot back in the center of the objective.

If your objective lens is in an adjustable cell, the actual collimation is easy enough. Insert your (Newtonian) Cheshire sight in the focuser in place of the laser. Shine a flashlight into the side port of the Cheshire, and have a look through the peep-hole. You will see one or two (or three depending on your lens) circles of light, reflections in the objective. If you only see one, your collimation is good. If you see more than one? Uh-uh…you’ve got work to do.

An adjustable objective cell will almost always be collimated with three pairs of push-pull bolts spaced 120-degrees apart. Observe the reflections. One should be toward the center of the objective, and one off to the side. Pick the pair (or pairs) of bolts opposite the reflection that is off to the side, loosen the push screw (the longer one) slightly, and tighten the pull screw. Go back to the Cheshire and look. Did you move in the correct direction? If so, continue till the circles merge. If not, tighten push and loosen pull. When you are done, do a check with the laser again to make sure the spot is still hitting the center and adjust the focuser again if necessary (and double check with the Cheshire following that). I did all those things and was shortly ready to star test again.

Collimation verified on bright Rigel, it was time for some fun with Luna. In truth, I didn’t know what to expect. I began at low power with an old 82-degree 30mm eyepiece I got from Herb York many a Moon ago. “Dang! Awful sharp!” But it wasn’t just sharp; the pre-first-quarter Moon was also amazingly color free. Sure, there was a little purple, including a thin line along the limb, but when I held my eye on axis, it was minor, as you can see in the iPhone shot I snapped by the simple expedient of holding my cell phone up to the eyepiece. This picture does a good job of showing exactly what I saw.

While the Moon was bright—my collimation exercise had allowed time for astronomical twilight to come on—one thing other than brightness of the subject can make chromatic aberration appear worse: higher magnification. I retrieved the 4.7mm ocular I’d used during collimation and had a look. At 255x there was no doubt there was “excess color.” Not just along the limb, but in the shadows, which now had a distinct violet hue. However, it was surprisingly unobtrusive and the view was still sharp even in average seeing. I had a #11 yellow-green filter on hand, and using it immediately banished that moldy oldie “Purple Haze” from my soundtrack, but I didn’t think it was necessary and preferred the view without it.

One of the beauties of a big refractor is or should be that its unobstructed nature and contrast characteristics allow you to use stupid high powers considerably in excess of the mythical “60x per inch of aperture” limitation. OK. What would Ethel do with the 4.7 in a 2x TeleVue Big Barlow to the tune of 510x? The seeing was not quite good enough for that much power, but Ethel accepted it willingly nevertheless. The image was still sharp enough considering the state of the atmosphere, and the color was still decently controlled. 510x on this inexpensive 6-inch? Kinda amazing if you ask me.

What else was amazing? That silly little Celestron VX mount. With the Moon high in the sky, I was using the GEM with its tripod legs fully extended. Even then, the eyepiece was low to the ground—but bearable. With the legs all the way out, I was still able to focus easily at 510x, and what shakes there were didn’t hinder my enjoyment of the stark lunar landscape.

What else did I look at on this evening? I did a tour of the prominent deep sky objects, more as a comparison of image quality before and after fine-tuning the collimation than anything else (maybe some better, not like night and day), but the main course was the Moon. I just couldn’t get enough of her in the mighty refractor, and the photo above is a mere suggestion of the beautiful images that appeared before my eyes. I probably cruised the Moon for a good two hours before my feet got cold, the signal that it is time to end an observing run.

Hermione

Hermione Granger
As I mentioned in my initial report on my new SkyWatcher Pro 120 ED refractor, Hermione Granger, her primary task would be deep sky imaging with my DSLRs. I’d actually already done some of that beyond a quick snap of M15 through a layer of clouds. I’d spent a couple of evenings with a far more challenging target, the Bubble Nebula. The telescope acquitted herself well riding on the CGEM mount.  While I could no doubt have done pretty well imaging with the 120 on the smaller Celestron VX due to the telescope’s relatively light weight of 11.5-pounds, I thought the CGEM was a must on these windy winter nights.

I was pleased with the Bubble from my less than perfect backyard. No, the images were not comparable to what I could have obtained from even our club’s semi-dark observing site, and the need to image through a mild LPR filter gave bright stars a rather odd look and applied a hard to banish color cast to the images, but not bad, not bad at all. Heck, if somebody had told me 20 years ago that I’d be getting recognizable pictures of the Bubble from my suburban backyard someday, I’d have laughed in their face.

Given my good results with the Bubble, I was eager to do more and was anxious to get started when the next front passage brought clear (if somewhat unsteady) skies. The target this time would be even more challenging, I thought:  NGC 281, the Pacman Nebula. Not only would I be going after a harder subject, a new piece of gear would be thrown into the mix, a new guide camera, a QHY 5L-II.

I’d been using the same camera for auto-guiding for ages, an Orion StarShoot Autoguider, which is actually the original QHY guide cam with an Orion nameplate slapped on it. It worked. I’d never been unable to guide with it. It had a drawback, though. Fairly low sensitivity. Nevertheless, using it in concert with a 50mm finder/guide-scope, I never landed on a field where I couldn’t find a guide star. Admittedly, some of them could be a little low in the signal-to-noise ratio department, but I was always able to guide OK.

There was a more important reason for buying a new camera than just having a larger selection of good guide stars to choose from, however. Before you know it, another terrific Mars apparition will be upon us. I wanted to be prepared for that, and since I didn’t have a monochrome planetary imaging camera, it seemed like a good time to invest in one, one that could also be used for guiding (the StarShoot is monochrome, but cannot normally be used for imaging).

Which new guide camera? I gave some consideration to the Starlight Xpress Lodestar, which gets rave reviews, but I didn’t want to spend 600 dollars. Instead, I narrowed it down to two much less expensive cams, one of which was the ZWO ASI120MM. I have the color version of that camera (which was made before ZWO began added ST-4 guide outputs to their cameras) and it seemed like a natural. I knew the mono ZWO was sensitive, and I’d had a good buying experience with ZWO. However, my Chiefland friend Paul Lavoie told me he had never had any luck using the ZWO with a USB extension cable. In some cases I would need a longer run of USB to the camera, so that was a strike against it.

What Paul was using when I was at CAV in November was the QHY-5LII, a little guide/planetary cam that contains the same 1/3-inch sensor as the ZWO. I watched it in action and was impressed. It was obviously very sensitive and was light in weight and amazingly small, about the size of as a 1.25-inch eyepiece. I was impressed enough to eventually turn over my credit card number to a QHY vendor, the primary QHY vendor in the U.S., Astrofactors, which has an excellent reputation for service and support.

One caveat? If you want this camera, get the QHY badged version. Orion has their own version of the QHY 5L-II, which they call the StarShoot Autoguider Pro.  The Orion Pro and the QHY 5L-II are quite obviously the same camera save for one difference: the price.  The Orion version is $379.00 compared to $249.00 for the QHY. You do get some imaging software with the Orion version, but it certainly is no better than the freeware program I use, Firecapture.

The QHY arrived quickly, was nicely packaged in a little metal tin, and included a parfocal ring, an extension barrel, a (fairly short) USB cable, and an ST-4 guide cable. There were no instructions included, but they were easy to find on the QHY website. Same with the drivers; there was no disk in the package, but there was a card with a url for downloading them. That is maybe a good thing, since it ensures everybody gets the most recent version. I was impressed by both the packaging and the cute little camera. It comes in various metallic colors; I got the attractive chrome-barrel version.

Getting it up and running was simplicity itself and would not be a challenge for anyone who’s used a similar camera. Download the driver package, click on it (it’s a .zip file) in the downloads folder, and install it. Plug in your camera. That’s it. When I brought up PHD2, I was able to select the QHY without a hitch.  Clicking “loop exposures” in PHD2 and removing the camera’s lens cap resulted in an immediate whitening of the display, so it was obvious it was working from the get-go. “Simple. Neat. No trouble at all,” as Mr. Poe would say.

The new Stellarium...
Out in the back forty with Hermione and the CGEM, things went in similarly smooth fashion. First up was focusing the new guide camera with my guide scope, an Orion Mini. I’d screwed the extension nosepiece onto the camera and positioned the parfocal ring a similar distance from the chip as on my StarShoot. Pointed to Caph, which I figgered would show up even way out of focus, and began looping frames with PHD2. But not a thing did I see. Just some noise. What the—?   “Rod, you dummy, it helps to remove the lens caps from the guide scope.”

That minor detail seen to, I set the exposure to 1-second and tried again. My first tip-off that this is one sensitive little camera was that I didn’t just see one large out of focus star-disk (Caph), I saw many. I repositioned the parfocal ring a bit to get focus nearly in, and then tightened the camera down with the mini-guider’s set-screws. Final step was refining focus by screwing in/out the guide scope’s objective assembly while observing the s/n ratio on one of the stars on PHD2. When focus was good, I locked the mini-guider’s objective down and we were ready to roll.

With the guide scope in focus, I was simply gobsmacked at the difference between the 5L-II and the StarShoot at my usual 1.5 – 2-second guide exposures. With the StarShoot, I’d have seen stars, but some would have been on the dim side. With the new one, the screen was full of bright stars. Only drawback? At 2-seconds, PHD2 said more than a few of them were “saturated,” (a no-no). I had to back the exposure off to 1.5-seconds to de-saturate the star near the center which I fancied as a good candidate. 1.5-seconds is maybe not quite as good in poor seeing as 2-seconds, but it worked fine. I also tried 1-second exposures, and, as with 1.5-seconds, there were many more stars visible—many more—than there would have been with the StarShoot.

Backyard Bubble...
Actually, the guide camera was not the only change on this evening. The other was the software I used to send the telescope on gotos. What I’ve been using for quite a while is Bisque’s TheSky 6 Professional. Works perfectly. Well, but for one thing. This no longer supported software (it’s long since been superseded by TheSky X) can no longer automatically download comet elements, and I had the wild idea I was going to stay up late and shoot Comet Catalina.

What to do? Normally, I’d have switched to Cartes du Ciel, but I’d been having problems with that program on my laptop, getting crashes and weird error messages. I’d tried several things to exorcise these demons, but nothing had worked. What then? How about Stellarium? I’d used this program now and then and had been somewhat impressed. And, I’d recently been told it was in a new version and better than ever. So, I downloaded and installed the new Stellarium and found it easy to automatically update its comet elements including those for Catalina.

How was the new Stellarium otherwise? Version 0.14.2 is impressive. So impressive that I may devote a blog entry to it some Sunday soon. Suffice to say that it is more than powerful enough to do my admittedly rather simple tasks. Honestly, I never needed the power of TheSky 6 Pro and never used even a fraction of its many features. Stellarium looks good and works good. Not just inside on the desktop, but outdoors in concert with the telescope.

Let me also give a big shout-out to the developers of the Stellarium add-on program, Stellariumscope. While Stellarium now has built-in drivers for several telescopes/mounts, I preferred to use the excellent new Celestron ASCOM driver. To do that, I needed to make Stellarium ASCOM compatible, and you do that with Stellariumscope. The combination of Stellarium/Stellariumscope works well and simply. Search for your object. When it’s found, center it with the space bar. Hold down CTRL and press “1,” and the scope goes to it. That is all there is to it, and is really all I need astro-software to do at the moment.

Before I began acquiring images, I wanted to do one other thing. There was that bright Moon hovering overhead, and I couldn’t resist sending Hermione to it. How would she compare to Ethel there? While Ethel did a fine job, there was no denying Hermione was better. As I’d expected given her amazing color-free performance on Sirius, nary a hint of false color did I see. And so sharp! This is not to take anything away from the achromat, but the 120 is just flat out amazing on everything.

The Pac-meister...
Next, I CTRL–1ed my way to the Bubble Nebula, set my fave DSLR control program, Nebulosity 3, to take 35 180-second exposures with the Canon 400D, made one last check of everything, pushed the “Capture Series” button and headed inside to watch TV in the warm den while Hermione did all the work. Before decamping, I did take a look at PHD2. It was guiding with an RMS error of between 1 and 1.5-arc seconds. That is quite good enough to ensure smallish round stars with the refractor so I didn’t feel the need to mess with it.

Over the course of the next several hours, the scope and computer did their thing. I’d wander out on to the deck (where the computer is; the scope is on the ground) to check on the progress once in a while, but I really didn’t have to. The telescope and CGEM continued to guide well with PHD2, and Neb wasn’t missing a beat.

At the end of the evening I was rewarded with the nice picture of silly old Pacman you see here. Oh, maybe it wasn’t quite that easy. Next day I stacked subframes, did some preliminary processing in Nebulosity, and some further tweaking in Adobe Photoshop and Adobe Lightroom, but it wasn’t hard. Yeah, my picture would have been better from a dark site, but at a darksite I wouldn’t have had a warm den and a big-screen TV to enjoy while the sequence was acquired. At any rate, I was at least as pleased with Hermione’s Pacman as I had been with her Bubble. And, no, I didn’t stay up for the comet. The temperature was dropping steadily, and so were my eyelids. I pulled the Big Switch as soon as the last Pacman subframe came in.

What’s next for my refractor girls? Not only is there a waxing Moon in the sky, there’s more rain on the way, so I suspect all will be quiet here till the next dark of the Moon cycle. When that comes, I hope to get Ethel out to the club site for some visual fun. If I get really sanguine, I may even cart out a load of gear and do some real deep sky imaging there with sister Hermione.

That’s for later, though. For now, I am just so pleased about both my new scopes. Both will, I think, add a lot to my (modest) observing programs. If nothing else, they’ve served to do one very important thing:  get me excited about astronomy again after a few months of the semi-doldrums. Can’t ask for more than that. 

Excelsior, y'all.

Sunday, January 17, 2016

 

The Refractor Way Part III


Let’s cut to the chase.  A constant in amateur astronomy since I was a boy in the 1960s has been that no matter what sort of telescope you own or like—Newtonian, Schmidt Cassegrain, whatever—there is one you’ve longed for even if you won’t admit it to yourself. One telescope you’ve dreamed about over the years. Yes, friends, I am talking about that holy grail of amateur astronomy, the six-inch refractor.

You want one, I want one, we all want one. For those of us who lived through the sixties, the six-inch lens-scope is especially hallowed, since back then it was an almost mythical beast, one whispered about in hushed and reverent tones by the most knowledgeable and illustrious among us, gurus like Patrick Moore. The closest most of us ever got to a six was seeing one occasionally pictured in the Unitron catalog, where its price was listed as an astounding $6,000. That is equivalent to at least $40,000 today, and maybe as much as $75,000. Back then, 6K was over half the cost of a very nice home. In other words, a big lens-scope was the impossible dream.

And for decades a six-inch refractor remained just a dream for the average amateur. Things began to change in the waning days of the twentieth century, however, when the Chinese telescope industry broke the bonds of 60x600  refractors and began producing decent gear. One of the more impressive offering from one of the premier Chinese firms, Synta, once they found their feet was, yes, a six-inch refractor. It wasn’t dirt cheap at first, with the earlier examples going for something over $1500 but that was a darned sight better than $40,000.

Actually, there were several companies, including Astro-Physics and Takahashi, selling six-inch refractors for considerably less than 40 grand. And not only were they selling sixes, they were selling apochromatic, color free, sixes. However, while not as costly as that old Unitron achromat, they were certainly not cheap, and might as well have been 40K as far as I was concerned.

The Synta six, sold under both the SkyWatcher and Celestron brand names (even before Synta bought Celestron), had another plus in addition to its price: its focal ratio. One of the things that formerly made a six-inch refractor a crazy dream was the mount one required. Do a six at f/15 or f/20 and you have one hell of a long, heavy tube that demands a big mount and a tall, heavy pier or massive tripod. The Chinese got around that by focusing on fast achromats, initially f/8, but soon also f/5 and f/6. That made mounting one on a Great Polaris clone mount like the CG5 at least somewhat practical.

Of course, take a six-inch achromat down to f/8 and there’s a big penalty in the form of chromatic aberration. Why do you think the Unitrons sported such long tubes? To keep the color purple suppressed. I figured the color wouldn’t be just bad in one of these telescopes, but kaleidoscope bad. I didn’t want any of that mess, so all through the nineties and into the oughts, I resisted the urge to finally get a six. Who wanted something that made a Short Tube 80 look like an APO?

I made that determination merely by assuming—and you know what they say about that word. I hadn’t actually looked through a Synta (or Meade; they were now in the six-inch achro game too with their LXD55 rig), but I was sure I wouldn’t like one. Over the past decade, I did get quick peeks through a couple of Celestron 6-inch f/8s, but not long enough looks under good enough conditions to allow me to really make up my mind about these telescopes, much less change it.

That change finally began a few months ago when a new club member showed up at our dark site with a Celestron f/8 riding on an Atlas mount. I was able to spend some time at the eyepiece, and was fairly impressed. On the deep sky, performance was very much like what I’d have expected out of the average C8. In addition, at f/8, the scope could provide some nice semi-wide-field views. Contrast was actually impressive, and despite fairly poor condition the telescope pulled its own weight on Jupiter. Most of all…it was a six-inch refractor…and came with a big helping of that ineffable je ne sais quoi.

Color? There was color on Jupiter and on bright stars, but it was not nearly as bad as I’d expected. Whether because in my mind I’d exaggerated the degree of chromatic aberration one of these scopes would present, or because my middle-aged eyes are just not as responsive to the dread purple haze as they once were, I didn’t know. All I knew was that while certainly noticeable on bright stars and the planets, it was not debilitating, not for me.

Thus, the wheels began to turn slowly, ever so slowly. I’d occasionally tell my friend Pat that I was thinking about a 6-inch refractor. Either the trad Synta f/8 or one of the new Explore Scientific (JOC) f/6.5 jobs. I talked about doing the deed, yeah, but still couldn’t quite muster the courage to get off the C8 fence. Not until a couple of weeks ago.

One a.m. I was shooting the breeze with the Cloudy Nights gang on the refractors forum, a place which I seem to inhabit frequently of late. The topic? Six-inch achromats. I registered my opinion that a 5-inch class ED scope was a better bet than a darned old achromat. The chromatic aberration inherent in a large, fast achromat would, I said, reduce its performance to the level where it was worse, considerably worse, than that of the smaller telescope.

One of the folks participating in that round table was my old friend Barry Simon, the managing director of the Deep South Regional Star Gaze and President of New Orleans’ Pontchartrain Astronomical Society. Barry must have noted a certain wistfulness beneath my hard-edged “get an ED” line. Or maybe he just saw me as a lost soul in need of rescue. But he was soon emailing me to tell me he had a six-inch f/8 achromat for sale.

It was, Barry said, a nice one, a “Kepler,” once marketed by Zhumell. It was only a few years old and barely used and he was wondering if I’d be interested in it. Would I? The (very) reasonable price he quoted was enticing, doubly so since I had some dollars in my hot little hands following the sale of yet another telescope, my old Criterion RV-6. So, after considerable deliberation and soul searching, I told him I was indeed interested. Oh, hell, who am I kidding? Deep down I knew I wanted it from the get-go, and in just a few minutes I was emailing to say, “Yes, Barry, I want a six-inch refractor.”

Turned out Mr. Simon would be in the Gulfport, Mississippi area (halfway between New Orleans and Mobile) on business shortly, and that he’d be happy to meet me there so I could pick up the scope. Honestly, I could hardly wait. A little Googling (or more properly Binging) turned up favorable reports on the Zhumell. It sure looked good with a large and lovely white tube. While it was apparently made by another Chinese company, it did look a lot like the JOC scopes sold by Meade and ES save for the fact that their weird short, fat dewshields had been replaced by a more normal looking one.

Just before I was to pick up my new refractor, Barry emailed that he’d been able to get the Zhumell out into his backyard for a test, and had been favorably impressed both by the optics and by the fact that the scope did fine on his VX mount. I was very happy to hear the latter, since it made my plans for the scope more practical.

What was I going to do with a six-inch refractor? My bag right now is DSLR imaging. Imaging through my 120mm SkyWatcher ED refractor on my CGEM mount. That pair has worked well. So well that I’ve been awfully bored during observing runs. Start the scope auto-guiding and tell Nebulosity to begin firing off  a series of sub-frames and there is not much else for me to do. I thought it would be nice to have a visual scope to take to star parties so I’d have something to occupy me while the telescope, Hermione, took pictures. That was where the 6-inch came in, and being able to use it on the VX meant I wouldn’t have to drag my Atlas along in addition to the CGEM.

On the appointed day, I motored the one hour west to Gulfport to meet Barry and have lunch at the local Newk’s. The trip was pleasant enough, but I gotta say I was in an agony of anticipation and it was difficult to keep the 4Runner at a somewhat reasonable speed on I-10. Finally, the exit, and after a couple of wrong turns I was pulling into the parking lot of the restaurant where I spotted Barry and another old buddy, Gabe Dickens, a well-known observer from the Gulfport area who would be joining us for lunch.

I was happy to see Barry and Gabe, of course, but the object of the trip was what was on my mind. There she was, sprawled across the backseat of Barry’s car. The refractor. The SIX-INCH REFRACTOR. My first impression when Barry pulled her out? “She’s big. Much bigger than I thought.” Second impression? “She’s awful pretty. Prettier than she looked in those Internet pictures, with a spotless and positively glowing white tube.” My third impression, which came when Barry handed her off to me? “Heavy. At least twenty pounds. Maybe more. Will the VX really do the job?”

After depositing the new girl in the 4Runner’s cargo area, it was lunchtime. This was my first visit to Newk’s, which is a step up from the fast food joints, and features a rather upscale menu for a casual and inexpensive sort of place. I ordered the shrimp and avocado salad, and settled in for a pleasant half hour of eating and talking telescopes and the local amateur astronomy scene with Barry and Gabe.

As good a time as I had, I must admit I was preoccupied. I was antsy to get the refractor home and get her settled on a mount, which I now suspected might have to be the Atlas or the CGEM. Holding that big tube in my arms, I had become doubtful about the VX. Yes, a six-inch f/8 refractor is about the same length as a six-inch f/8 Newtonian, but the weight is kicked up several notches. You just don’t realize how heavy a refractor in this class is until you pick one up. Then you understand why the mount on that Unitron f/15 had to be such a monster.

Home again, I deposited the OTA in the usual scope staging area, the sun-room, and did some thinking. It sure would be nice to be able to use the VX for this telescope, and since I’ve used C11s quite successfully for visual work with CG5 class mounts, I decided to give the VX a go after all. I’d try the refractor on the mount in the house first and see how it went before going to the backyard.

The first thing to be challenged was not the VX, but me. It was not a pleasure getting the big tube onto the GEM. Taking the utmost care, I finally got the refractor’s Vixen format dovetail settled into the VX’s saddle, tightened down the bolts, and triple checked to make sure the scope was fully seated before letting go. The mount didn’t come crashing to the floor under the weight, so I proceeded to roughly balance in RA and declination. Barry had warned me it would take over twenty pounds of counterweights to balance the tube, so I had already mounted two 11-pound Synta  pancake weights on the declination shaft.

With the scope reasonably if not perfectly balanced, I fired up the VX and did some fake alignments and gotos to see how it would respond. I wasn’t overly worried about the weight of the tube, which is less than that of a C11, but I was worried about the lever-arm effect of the refractor’s OTA which is, of course, considerably longer than the tube of the SCT. “Hmm…motors sound normal…she’s pointing in roughly the right directions…we are go for first light.”

Reassured, I disassembled everything and moved mount and scope to the backyard, once again struggling with the OTA in the course of getting it on the VX. While the mount had responded well with the big tube when it came to slewing, I wasn’t sure how shaky the combo would be. Though I didn’t extend the VX legs all the way, I did extend them almost all the way, about 80%.  I knew that if I didn’t, I would be crawling on my belly like a reptile when viewing objects anywhere near the zenith. I thought I’d try the setup with the legs that far out, and if it were too shaky, I’d add Celestron’s vibration suppression pads to the mix. If that didn’t work, I’d just have to collapse the tripod and think about cobbling together some sort of half-pier extension.

We all joke about the New Telescope Curse. The propensity of the skies to cloud up with the arrival of any new telescope, no matter how small. In theory, my purchase of a six-inch refractor should have caused severe thunderstorms if not tornadoes, but it looked like I was to be spared the curse. Or maybe the weather gods were just toying with me. While the skies were not cloudy, not completely cloudy, they were not exactly clear either. Not by a long shot. Haze. Drifting clouds. Periods of overcast. I thought the sky would be just good enough to tempt and tantalize without allowing me to really see what the refractor could do. Nevertheless, I persevered. I had a new scope and I was going to take first light with it.

After getting the (nice) 50mm finder aligned on a distant tree, I proceeded to goto alignment, doing my normal 2-4 routine with the Celestron hand control What did the bright stars look like in the 12mm reticle eyepiece? They looked OK; certainly they were not purple hued horrors, but it was not quite dark enough, I thought, to tell the tale color-wise.

When I finished the goto alignment (I didn’t bother with an AllStar polar alignment; one just isn’t needed for visual work), it was rubber-meets-road time. As with Hermione, I chose a bright star as our first light object. Vega, which I’d used with the SkyWatcher, was now too low, so Deneb was the target. When the slew stopped, I inserted a 16mm eyepiece, my 100-degree Zhumell Happy Hand Grenade, and had a look…and… Not bad. Not bad at all. Once you made allowances for the night’s punk seeing and my astigmatism-riddled eyes, the star actually looked pretty good.

Was Deneb colorless? No. There was a small purple halo, but it was small and relatively faint and not disturbing. To my eyes, Deneb just look any worse than a similarly bright star does in our 4-inch f/6.5 AR102 refractor. Otherwise? Near as I could tell under the conditions, the star test looked good. Collimation a bit out (from what I could tell with the star boiling and jumping) but not terribly bad. Later in the evening, I had a look at Rigel at various magnifications high and low. Purple halo? Yeah. That bad? No, and the star’s tiny companion was easily visible. Still later, I dared to turn the scope to Sirius. If the seeing had been better the view would have actually been surprisingly nice. What made it ugly was not so much the chromatic aberration, but the seeing-induced bloating and boiling.

How was the telescope otherwise? As far as focal ratio goes, 150mm at f/8 is a nice place to be. With a 30mm eyepiece it approaches wide field, but the scope packs enough millimeters to get you to 200x without resorting to overly short eyepieces. Contrast seemed good given the hazy conditions. The focuser? Typical Chinese rack and pinion, but not bad. It had no problem with my heaviest eyepieces, and was smooth enough if not quite in the “buttery” category. The VX’s stability under this load was a nice surprise. At 250x, the shakes died out in about two seconds.

Didn’t I look at any deep sky objects? Sure I did. M37, NGC 457, M35, and, of course, M42. How did they look? Not very good. I was viewing through a layer of haze as astronomical twilight came on, and I couldn’t venture a guess as to how the six-incher’s views of them stacked up to their appearance in the 5-inch SkyWatcher ED. Oh, there was a hint of that refractor goodness, of tiny diamond hard stars, but only a hint on this night. I had the good sense to pull the big switch before I got frustrated, and repaired inside to watch the DVDs of Batman: The Animated Series I got for Christmas. The good news was that the next evening was predicted to be considerably better.

Night two certainly was better, at least transparency wise—seeing was still below average. It appeared there was not a chance of clouds intruding, though, so I set out to give the new girl a chance to prove her mettle over several hours. On what? As I have told y’all before—frequently—if you go into the backyard without an observing list, you won’t see much. You’ll look at M42 and a couple of other best and brightest DSOs, decide you’ve seen it all, and wander back inside to watch reruns of Jersey Shore. Not me. Not on this night. I had a list.

Or, to be more exact, I had a book. One of my favorite astro-books from the 1980s. Astronomy Magazine Editor Dave Eicher has done a lot for our avocation over the years, but if all he’d ever done was write The Universe from Your Backyard, he’d still be a standup guy in my opinion. This color, large format book breaks down the best deep sky objects constellation by constellation, and is the perfect companion for old fashioned backyard star gazing.

I thought I’d start in Auriga, but first I wanted to run a little test. In the above-mentioned Cloudy Nights discussion, I'd asserted that a 5-inch ED scope will beat a 6-inch achromat on anything. Was that true, though? From what little I’d been able to make out on first light night, the images the 6-inch was capable of delivering were not the horror of chromatic aberration induced color and blurring I’d expected. So, what might the 6-inch do on a fairly dim DSO I’d recently observed with the SkyWatcher 120? Like NGC 2158? This little “companion” cluster to Gemini’s M35 was climbing high into the sky now, and I clearly recalled how it had looked in the 5-inch (or almost 5-inch if you insist) a couple of weeks before.

When the scope landed on the cluster, I took a long look at a variety of magnifications. The verdict? At comparable powers, the 6-inch showed NGC 2158 more convincingly than the 120 had, resolving at least a few more stars in the distant cluster at higher magnifications than the smaller instrument had. Thanks to the light pollution, it was not great in the new scope, and certainly not well resolved, but still noticeably better than in the 120, if not worlds better, just as you’d expect from a 30mm aperture advantage.

That informative task out of the way, and somewhat heartened by what the 6-inch had done, I began my tour of the winter sky with the help or Mr. Eicher, with the first object being the superb open cluster in Auriga, M37. What did I notice other than the fact that the group was awful pretty? That the Zhumell did a nice job of showing star colors. The red central star was particularly vivid. And how "little" the stars looked even at higher powers.

After I'd had my fill of M37, I next visited the other members of Auriga's bright galactic cluster trio, M36 and M38. They were nice, but not a challenge for the six, so following those beauties, I began to hunt dimmer quarry, beginning with a faint little patch of nebulosity, NGC 1931. This relatively dim peanut-shaped cloud can be a challenge for an eight-inch telescope under less than good conditions, so I didn’t really expect to see it in a six-inch, but there it was, even without a filter. I was mucho impressed.

So it went through all Auriga and Gemini, till I noticed Orion was now high above the trees to the east. Naturally I went there. I was feeling a bit chilled, and thought I’d wind things up with the Great Nebula. What was it like? Oh, it was great. When isn’t it great? Even in the light pollution there was plenty of nebulosity, with M43 actually beginning to show its comma shape. That was not what caught my eye, however. What did was the Trapezium, and specifically how yellow one of its stars looked in the refractor. I’m not sure I’d ever noticed the color contrast between this sun and its brethren to this extent before, but one thing is sure, the effect was lovely.

With M42 admired for an especially long time, I pulled the Big Switch and wrestled Big Ethel off her mount (I don’t have a cover large enough for her and didn’t want to leave her soaking in the dew all night). Why “Ethel”? That just seemed right. She’s on the large side just like Jughead Jones’ erstwhile quasi-girlfriend, and is for sure a different type compared to Veronica Lodge (the name borne by my high-toned 80mm Fluorite APO). She is certainly strong, though, given my experience with her on this night. And she also seems to have quite a personality.

Despite the nice views of night two, the next day I thought I'd better put the new telescope on my bench. Her collimation had obviously been at least slightly out, and since that was apparent even under fairly poor seeing conditions, I thought it warranted a look-see. Ethel's optical alignment was indeed fairly far off, but half an hour of squaring the focuser and adjusting the objective cell (via nice enough push-pull bolts) with laser and Cheshire was sufficient to put things right.

What is next for Big E? With the Moon coming back into the sky, I'll dare to turn her to that bright orb. Do I expect much from her on the Moon and planets? No. But I didn’t expect her to perform nearly as well as she did on the starry sky, either. 

Sunday, January 10, 2016

 

Smart Phones + Tablets + Amateur Astronomy: Where we are Now (Part II)


SkyPortal
As promised, here’s my next batch of astronomy programs for smart phones and tablets. Before we get to them, though, the big news in apptown, as it always is when it happens, is that there’s a new SkySafari on the street, SkySafari 5. I’m already using the iOS version, since the upgrade from 4 to 5 was free for the basic edition. I will most assuredly be upgrading to 5 on my tablet, too, probably to Pro when it becomes available for Android, likely in the next three – four months, I understand. Stay tuned. From the brief look I’ve had at the basic version of 5, SkySafari is better than ever.

More Planetarium and Deep Sky Stuff

There is little doubt, as I said last time, that SkySafari is the king of the hill when it comes to planetariums for smart devices, but just because it’s a good thing, that doesn’t mean it’s the only thing that may be of use to you. Do you like “free”? If so, check out Celestron’s SkyPortal. It’s based on SkySafari, so why would you choose it in preference to the real deal given the fact that the basic version of SkySafari costs a paltry ninety-nine cents at the moment? You probably wouldn’t—unless you own a Celestron telescope.

The draw with SkyPortal is that it allows you to control your Evolution telescope wirelessly. And you can do the same thing with many other Celestron scopes with the addition of Celestron’s SkyQ wi-fi dongle. That’s been the case for a while, but Celestron has just kicked things up a notch with a new version of SkyPortal that supports their StarSense automatic telescope alignment system. Yes, SkyPortal in concert with the SkyQ Link adapter will now talk to the StarSense camera and perform goto alignments without you having to squint through a finder or mess with the telescope’s hardware hand control.

Another planetarium that might strike your fancy is an old, old Windows favorite, Distant Suns. It’s been in an iOS version since almost the beginning of the smart phone revolution, is available in a standard and a “Max” version for a very reasonable $1.99 and $4.99 respectively, and comes in both Android and iOS flavors. Is it a SkySafari Pro with millions of stars and DSOs? No, but it is user-friendly, pretty, functional, and may be all some of you ever need.

While it’s not a planetarium program, an app I’ve found quite useful for my deep sky observing is one called “Deep Sky Browser.” This app was originally called “DSS browser,” and that is actually a more apt description of what it does. This is a simple but useful program that allows you to download images from the online Digitized Sky Survey and view them on your iPhone or iPad. Very useful when you’re hunting fuzzies and want to know exactly what your quarry looks like.

Deep Sky Browser
DSB doesn’t stop there. It also gives the vital statistics for thousands and thousands of DSOs (it will access the huge UGC galaxy catalog, though it lacks the ability to bring back PGC objects). It also makes visibility predictions for any of these fuzzies, and you can even interface it with your digital setting circles if you have a means of connecting the DSC computer to your phone. Useful, good, and inexpensive at $9.99. I hope the developer keeps working on this app, and considers turning it into a full blown observing planner. I also hope they eventually do an Android port. If there were one available, it darn sure would be on my Asus tablet.

Telescope Helpers

This is an area particularly suited for phones and tablets. You’ve always got one in your pocket, well, a phone anyways, so why not enlist their help in setting up your telescope? There is a surprising lot they can do in that regard.

Scope Help, available for iOS only, is (or was) a fantastic little app, combining a polar alignment helper, a compass, a bubble level, GPS, and more. The only problem with it is that at the moment it doesn’t seem to be available in the iTunes store. If you run across it, however, glom onto it. Thanks to Scope Help I don't have to carry a compass in my accessory case anymore.

If you can’t get Scope Help, there are alternatives that will do the same thing, if not in all-in-one fashion. One of these is “Polar Scope Align.” What it does is display a simulated view through your telescope mount’s polar alignment borescope showing where Polaris should be with regards to the reticle. Which polar scope reticle? There are numerous ones you can select…Takahashi…SkyWatcher/Orion…iOptron and more.

This is a really nice little app. It picks up your position data automatically from the phone’s GPS and shows the Polaris Hour Angle in case you need it. Simple. Neat. No trouble at all. Well, no trouble if you’ve got an iOS device. There isn’t a version for Android, alas. Luckily, there are similar good apps for Android, but this is what I use. If you’ve got an iOS widget this is a no-brainer:  get it, it’s free.

The next one isn’t really an astronomy app, but it’s useful in telescope setup anyway. Bubble Level is just that, a virtual Bubble Level on your phone or tablet that makes use of the device’s accelerometers. You get a choice of three level styles, including the circular level favored by amateur astronomers for leveling telescope tripods. Even better? It’s free. Best of all? It's in both Android and iOS versions. I don’t agonize over getting my scope tripod precisely level; that’s just not necessary.  I do level it, however, and this is much easier to use than any hardware store level.

Polar Scope Align
What’s troubling you, Bunky? Your goto telescope doesn’t have a GPS receiver and you don’t feel like giving the folks who made your scope’s mount a couple of hundred bucks for one? No problemo. You can get a free one that will work fine if you don’t mind manually entering latitude and longitude into the hand control during set up. Most phones and tablets have GPS, so why not take advantage of that fact? I’ve got several GPS apps, but the one I’ve used the most is the appropriately titled “Free GPS.” It’s not fancy, but it doesn’t have to be. It displays your current latitude and longitude and that is all you need for scope set up. Android and iOS versions.

Solar System Apps

I am not currently big on observing the Solar System, but I go through phases when I am and will undoubtedly be again, especially with a good Mars opposition on the way.  There’s plenty of Solar System stuff on iTunes and Google Play, and a surprising amount of it is even oriented toward observers. This is just a sampling of the apps I’ve found useful at one time or another.

Not only is Planets, which comes in both Android and iOS versions, free, it’s actually pretty useful. Useful enough that I’ve had it on my smart devices since the iPod Touch days. It’s somewhat limited, really only doing two things for you, plotting the positions of the planets (on a nice 3D sky chart), and giving visibility data. I wish it would do other things like show planetary satellites and GRS data for Jupiter, but it obviously does enough for me or I’d have ditched it long ago.

If you need the positions of Jupiter’s satellites, there is no more convenient way to get it than with a little app called “Jupiter Guide.” Not only does it show you the positions of the Galilean satellites oriented properly for your telescope, it also gives Great Red Spot transit times. Not bad for free. I’m sorry there does not appear to be an Android version, but I’m sure there are similar apps for that OS.

Everybody needs a Moon map, and why not put one on your smart device? One is somewhat easier for middle aged eyes to read than the Rukl book, and much easier to orient to match views in the eyepiece. What I like is Moon Map Pro. MMP displays a pretty airbrush style chart as the default, but you can switch to Lunar Reconnaissance Orbiter images. How many features are identified? 8,000. Maybe that’s not quite up to the level of the PC program Virtual Moon Atlas, but it is way more than I usually need. This is a great tool for the Lunatic with an iOS device. At .99 cents, how can you go wrong? I’d have paid at least ten times as much for this much utility and quality.

Planets
Miscellany

There’s more to iPhone astronomy than just apps to help with observing. Oh, those are my main focus, but I’ve found two non-observing programs I use frequently, and I suspect that if I took a good cruise through the iTunes and Google Play stores I’d find many more.

Who doesn’t love Astronomy Picture of the Day? The daily dose of astrophotographic goodness from NASA is a constant in my routine; I look at it every single morning, but I probably wouldn’t if it were just on my PC. There, I inevitably get bogged down with a writing project or Facebook or Cloudy Nights and forget to go to the APOD website. But since the APOD app is on my phone, I have developed the habit of clicking on its icon first thing every a.m. and never miss my daily pic. With the app, you don’t have to fool with a browser; just click and go. Free and in iOS and Android formats.

The NASA app is a lot like APOD, but with a wider ranging collection of images. You can get the APOD picture with it, but also images from NASA missions and a lot more. NASA The App doesn’t seem very well known compared to APOD, but it should be. Like APOD, it can be had in both iOS and Android versions, and it is, like APOD, free for the taking. Do so.

That is about it for this edition, y’all. A little short, I know. but there’s something else demanding my attention at the moment. A new telescope. No, not Hermione Granger, another new one about which you shall learn before long.

Sunday, January 03, 2016

 

Goodbye Betsy, Hello Hermione...


2015 was a year of changes for me. Not the least of which is one you may be aware of if you are a Facebook friend of mine:  I sold Old Betsy; she is gone. Yes, the telescope that’s been at my side as my faithful companion for the last twenty-one years has gone to live with new owners, a young local couple. Never thought that would happen, did you? Neither did I, neither did I.

I won’t wax nostalgic about all the fun Bets and I had and all the star parties we went to over the last two decades. No point in that. It was time. Far worse than letting go of my 12-inch Dobsonian would have been letting her sit out in my shop and rot. I was simply not using her, you see. What finally impelled me to say goodbye was realizing she had not had any significant time under the stars since November 2014.  I decided I’d be happier with the telescope in a new home where she’d be loved and used.

I didn’t give Betsy away, but I sold her for a very reasonable price. Nevertheless, I found myself with sufficient cash in hand to finance a new telescope. While, yes, I am reducing the head-count here—I’ve also gotten rid of two C8s so far—that didn’t mean I wouldn’t consider adding a new one. It would just have to be a telescope that fit in with my current interests, prime-focus DSLR imaging and casual visual observing. Most of all, it would have to be a scope I would actually use.

It surprises some people to learn I am a refractor-phile. Yes, I’ve long been known as “Mr. SCT,” in part because I have written two books and more than a few magazine articles about Schmidt Cassegrains. However, over the last decade or so refractors have easily become my second most used and loved telescope, and today are not far behind SCTs in my telescope pantheon—if they are behind SCTs at all.

Refractors are just so easy, especially for astrophotography. Sharp images, little cool-down, no fussing with mirror flop or focus shift, moderate focal length. There is no doubt they produce beautiful visual images, too. I won’t bore you with a paen to the TINY STARS a good refractor can present, even at high power. I’ll just say that for me (and maybe for you, too, if you reach way down into your soul) there is just something special about lens scopes.

So, yes, I’d come to love refractors, and had some good ones for both imaging and for visual use, but what I didn’t have was a big one, which in refractor speak is a 5 or 6-inch. While my 3 and 4-inchers can do well for imaging, there’s no doubt a 5 or 6 will pull in more stars, and that for visual a 5-inch refractor is where things start getting interesting.

So which would it be? A 5-inch or a 6-inch? I soon decided against a 6-inch. If possible, I wanted to stay within the modest budget provided by the sale of Betsy. Getting an ED/APO sixer would have meant tripling that at least. Sure, I could have gone “achromat,” but the major reason for doing so would have been bragging rights, being able to say I had a 6-inch refractor.

The ground truth is that a good ED 5-inch can beat one of today’s affordable achromats at most things. Certainly, imaging and image processing would be complicated by the chromatic aberration inherent in fast (f/6 - f/8) achromats. Also, while a 6-inch would have been OK on my CGEM mount, I thought a 5-inch would be better. And I thought a 5-inch would also be more than usable, for visual at least, on my Celestron VX GEM.

And so the hunt for a 5-inch APO began…

I ruled out the Astro-Physics and Takahashi refractors from the get-go. Beautiful scopes and wonderful performers, sure, but costing so much more than what my budget, even stretched to the breaking point, would allow as to not even be funny. I was also uncertain I’d live long enough to receive an AP130 given the notorious waiting times for that fine instrument.

I know better than to scrimp when it comes to quality, however. I wouldn’t be penny wise and pound foolish. I gave due consideration to the next tier down, the 5-inch aperture range telescopes from TEC and Stellarvue and William Optics. I was especially attracted to the WO FLT-132 and the StellarVue 130. Both would bust my poor budget, but not nearly to the extent of an AP or Tak, and both were beautiful and highly regarded. What if there were a way I could get a 5-inch more attuned to my modest means without sacrificing optical quality, though?

Perhaps the biggest recent change in the refractor scene, an almost revolutionary change, has been the appearance of reasonably priced 5-inch ED/APO scopes in the 1500 – 2000-dollar range. Yes, you read that right, 2K or less. The two leaders in this arena so far have been Explore Scientific with its JOC produced scopes and SkyWatcher with its Synta-made refractors. I began researching two candidates, the Explore Scientific ES 127ED, and the SkyWatcher Pro ED 120.

I eliminated one scope immediately. Explore sells their 5-inch refractor in two variants. The "Essentials" version is furnished with a white aluminum tube and looks a lot like the ES achromats. The other, the premium 127, uses the same optics, an ED triplet, but in an attractive carbon fiber OTA. I didn’t think carbon fiber was a necessity given our usually balmy wintertime temps, so despite its good looks I passed on the carbon fiber ES.

The other contender was the SkyWatcher Pro ED 120. At first, I was a little hesitant to give up 7mm and live with “almost” 5-inches, but much as I liked the ES scopes, I gradually began to turn more to the SkyWatcher. While the objective on the SW is a doublet rather than a triplet, one of its elements is of FPL-53, synthetic fluorite if you will, and all the reports I read said the telescope’s color correction was every bit as good as the ES’ triplet, and maybe even slightly better.

The more I researched, the more I came to believe the SkyWatcher was the scope for me. Not only were the optics (reputedly designed by a Takahashi refugee) admired, the scope came with considerable lagniappe compared to the ES. In addition to the OTA, the SkyWatcher package included a 50mm RACI finder, a pair of eyepieces, a 2-inch star diagonal, and, most of all, an aluminum case. The current ES packages seem to lack all these things.

There were plenty of finders and eyepieces and diagonals around here, but the case was a pretty big deal. For a refractor to live up to its ultra-portable reputation, it really needs a good case to protect it and keep it and its components organized, and it would be nice not to have to shell out more bucks for one.

In all my reading and asking around about the SkyWatcher, I only uncovered one thing about the scope that was routinely criticized, the focuser. While most users rated the standard Synta Crayford as useable, there was no pretending, I gathered, that it was within a country mile of a Moonlite or Feathertouch. That was OK. Given the amazing price of the Pro ED 120, which was on sale at Christmas for freaking $1399.00, I figured I’d be able to replace the focuser with a Moonlite if I had to. So the SkyWatcher it was. I grudgingly gave up my credit card number and spent a week in anxious waiting for the new baby to arrive.

The Unboxing…

The coming of the new scope was actually rather anticlimactic as such things sometimes go. I was surprised at how heavy the box was and half dragged-half carried it into the sun-room where I do my telescope unboxing. I was slightly disturbed at the sizable gouge in the box, but that turned out just to be in the outer carton and the telescope’s aluminum case was completely unharmed. Kudos to SkyWatcher for doing a good job packaging wise. Anyhoo, with the new kid out of her box, my impressions were, in no particular order:

·        Nice and light for a refractor in this aperture range. At just over 11 pounds and with a “reasonable” length of tube at its f/7.5 focal ratio, the 120 was, I thought, going to be very good on my prole VX and CGEM mounts.

·        A pretty thing. I must admit I prefer all-white telescopes, but the 120’s black/bronzish metal-flake tube and white trim is striking.

·       The focuser seemed OK. Stiffer than I like, perhaps, but smooth. And the smooth and easy fine-focus control made up for any stiffness in the course focus. One big plus was the wide focus range. I found I could rack this Crayford out far enough that I would not need an additional extension tube to bring a camera to focus with a standard prime focus adapter or field flattener.

·        Beautiful objective lens with faint greenish looking coatings. Very good coatings, I thought, since the objective seemed to disappear when I looked down the tube, even in fairly bright light.

·        Decent accessories. The included 2-inch diagonal looked good. Metal and hefty. The two 60-degree AFOV eyepieces, a 20mm and a 5mm? OK, and at least a modest upgrade compared to the “free” Plössls you usually get with telescopes these days. The 50mm finder was also fine, if not any different from what we are accustomed to seeing from China these days. The case was excellent, I thought. Not strong enough to ship the scope in, no, but more than good enough for hauling the 120 to star parties in the back of my 4Runner.

·        Tube rings and (Vixen format) dovetail? I’d have preferred the better rings furnished with SkyWatcher’s up-market triplet APOs, the Espirits. The 120’s tube rings are standard Synta. I believed they would do the job, but they were certainly not as pretty as those that come with the more expensive scopes. On the other hand, the dovetail was nicer than what I usually see on Syntas. Given the light weight of the OTA, I was pretty sure I would be able to use it and not have to upgrade to a Losmandy “D” setup.

First Light…

At mid-afternoon, the sky was not looking good, not good at all, which wasn’t a surprise given the sort of weather we’d had over the past month. But as the day wound down it suddenly became apparent there would be some clearing. By sundown, the sky overhead was looking better and better, though glancing at the horizon showed more bad-stuff clearly on the way. Speed was clearly of the essence, so I didn’t fool with the CGEM, assembling the VX instead.

Even before aligning the VX, I could tell the mount was going to be happy with the refractor. While the longer tube of this 11.3-pound OTA maybe put a little more stress on the GEM than my 14-pound Edge 800 with its short tube does, it was clearly not more than the VX could handle. It only took one 11-pound Synta pancake weight to balance the mount with the, 2-inch diagonal, and one of my (heavy) Ethos eyepieces.

With clouds beginning to flow back in as astronomical twilight came on, I didn’t waste time doing a precise polar alignment. Sighted Polaris in the hollow polar bore, did a 2+4 goto alignment, and we were off to the races with our first light object. Which was? Vega. No point in delaying; I wanted to know from the start what the excess color situation would be with this big refractor. What I saw was truly astounding:  in focus Vega was a pure white. On either side of focus, there was a tinge, but just a faint tinge of color. In focus, nada, zip, zilch. Hooray!

How was the mount’s operation with the refractor onboard? Even with the legs extended about 75% to allow me to comfortably view objects overhead (while seated in my observing chair), the shakes were minimal. Goto operation was normal with no hesitation of funky sounds from the mount. For visual, at least, the VX plus the Pro 120ED is a fine combo.

That was almost all I was able to accomplish on night one. Oh, I did scope out M15, M37, NGC 457, and a few other bright objects as haze and clouds built. How did they look? Pretty putrid in the poor conditions, but they still looked like star clusters should look in a good refractor: tiny stars even at 200x. How was field flatness? At f/7.5, very good. My higher quality eyepieces presented beautiful views field edge to field edge, and even my old Happy Hand Grenade 16mm Zhumell 100-degree did a reasonable job, similar to what it does in the Edge 800.

I was hoping to get a look at M42 on this first light night, but that was clearly not going to happen. It was obvious that by the time it was above the trees to the east we’d be completely socked in again. There was time for one more test. I inserted a heavyweight eyepiece, my 35mm Panoptic, sent the scope to an object nearly at the zenith, and did some experimenting with the focuser.

Not too bad, but there was some slippage with the big ocular. It was clear I’d need to adjust the Crayford if it were to handle my DSLRs and field flattener. That would be in the morning, though. The stars were winking out now, and I called it a night. I left the mount out in the yard (covered), but I brought the 120 inside. I just couldn’t bear to leave beautiful new baby out in the yard all by herself.

Adjusting the focuser proved to be fairly simple. Next morning, I mounted the OTA back on the VX, installed my Canon 400D and Hotech field flattener, and pointed the scope to the zenith. Using instructions I found on the Internet, I adjusted one hex screw on the focuser until the Crayford held the load of the DSLR and flattener with no slipping, but remained reasonably easy to focus with the coarse control.

The Naming of Telescopes…

Sometimes you do get thrown a bone. The Saturday night after receiving the 120, the Moon was old and the clouds were gone for a while. I headed to our club dark observing site about 30-minutes to the west. It’s not pitch black dark, but the Milky Way is easy on any halfway decent night and I thought that if the weather held I might have a chance to see what the new telescope could really do.

I actually did get that chance, though my two fellow club members, Taras and Ken, and I were only given a little over two hours of good conditions. The Milky Way was visible, but only faintly visible and then only for the first hour of darkness.  Still, that was enough time for the new girl, again set up on the VX—this would be a purely visual night—to show her mettle.

First object after astronomical twilight was the great globular cluster in Aquarius, M2. In my opinion, this beauty is one of the most overlooked globs in the sky. Maybe because it’s a trifle low for our northern brothers and sisters. All I know was that it was a wonder in the refractor, even at 30x, and the more I increased the magnification, the better it looked.

I topped out at just under 200x with my new Explore Scientific 4.7 mm 82-degree eyepiece (didn’t bring a Barlow), and M2 was simply stupendous at that magnification with tiny stars and plenty of resolution across its face. I really didn’t think its appearance was much different from what it is in an 8-inch—and I’ve viewed this one countless times with my C8s. Well, except maybe that the stars were tighter in the refractor. Heck, my two buddies and I didn’t think the view under these conditions was that much worse than what it was in Taras' 15-inch Dobsonian.

That was pretty much the story with everything I observed. Very similar, all in all, to what I’d have seen in an 8-inch, but with that refractor zip added. What didn’t I get to try? The Moon or a planet. The Moon didn’t rise till long after the clouds intruded, and there were no evening planets on hand. Given the way the scope handles bright stars, however, I have little doubt she will be good on the Solar System.

Most surprising DSO of the night? Had to be the Helix Nebula. I wasn’t expecting a heck of a lot out of NGC 7293. The big planetary was low and on the outskirts of the Mobile, Alabama light-dome. I sent the VX that way anyway, inserting my 30mm “finding” eyepiece, an el-cheapo GSO that came with my 10-inch Dobsonian. Why I did that, I don’t know. Such a low power, 30x, would surely render the big nebula invisible in the sky glow.

Nope. Even at that low magnification and with the resulting bright background, the nebula was still visible as a round spot at field center. That is testament, I think, to the superior contrast characteristics of a good refractor. I didn’t mess around at low power long, replacing the 30mm with my 13mm Ethos and affixing an OIII filter to that.

At 70x, the Helix was starkly visible. While the donut hole was not easy, it was there. Bumping up to 112X with the 8mm Ethos further improved the view, and, as I continued to stare, I began to pick up the arc of nebulosity outside the main annulus. What it reminded me of was the way the Helix looked with a C8/OIII years ago at the old Deep South Regional Star Gaze at Percy Quin State Park near McComb, Mississippi, where the skies were considerably better than what I had on this night. All I knew was that what I was seeing was marvelous, and proved to me that a 5-inch refractor can be a satisfying visual instrument for the deep sky.

So it went for a while longer, till haze began to drift in in advance of the next storm front and we called it. I was just thrilled. The views provided by the new scope were everything I’d hoped for. The concern I’d had about the focuser had also evaporated. Oh, someday I may still replace it with a Moonlite, but over the course of the evening I didn’t have any problems with it and didn’t even give it any thought—it just worked.

Only one thing was left. The naming. While I have often told you, dear readers, that you should look upon telescopes as tools, there is no denying I don’t always practice what I preach. In spite of myself, my telescopes inevitably become more than just tools. They become my friends with individual quirks and personalities, and I have to give them names. At the end of this evening, the SkyWatcher's name was obvious; I didn’t even have to think about it. Folks, meet Hermione (Granger). “Herminone” because she is clearly magic.

The Final Test…

There was no doubt after my dark site run that Hermione would get some use as a visual scope, but that was not why I bought her. I have an excellent 10-inch Dobbie for visual. The main impetus behind acquiring a 5-inch APO was to have an imaging scope with a little more aperture and focal length than my smaller APOs, but less focal length than my Edge 800 (which comes in at 1400 mm with a reducer). So, I wanted to give Miss H. a clean bill of health imaging-wise as soon as possible. That happened just as the Moon was coming back into the sky, but before the wave of pre-Christmas storms that are still plaguing the Gulf Coast began to roll through.

Actually, I had little doubt Hermione acquit herself well for imaging. My main concern was with the whole package, scope and CGEM. I had yet to try to auto-guide the Celestron mount in the months since I got her. The main reason for that being the terrible summer and autumn weather, of course. It’s been bad, and the two major imaging expeditions I did this year, one to the Deep South Regional Star Gaze, and one to the Peach State Star Gaze, involved targets well suited to my 80mm APO, which is just fine on the VX—a lot easier to haul around than a CGEM.

Wouldn’t you know it, though? By the time the mount and Hermione were set up (I used an ADM Vixen-to-Losmandy adapter to get the 120 on the CGEM), the sky was going south again. That meant I was not able to spend any time tweaking the settings in PHD2. I went with the stock settings in the brain icon, firing off 20 2-minute exposures of M15. I believe I could have gone longer than 2-minutes per sub with PHD2, but the background was bright enough in 120-second frames that I didn’t dare expose longer. Building haze was making my normal light pollution worse, scattering the glow from the subdivision’s countless Christmas lights till the sky was a near Technicolor mess. At any rate, the stars were perfectly round in every sub. The only ones I threw out were a few where drifting clouds had passed through the field.

My thoughts on the results shown here? Darned good considering the conditions. If I ever get another clear night, I’ll tweak PHD2, but given my modest requirements, I’d say guiding was good enough as is. Certainly it was a lot easier to image with the refractor than with my focal-reduced C8. Any light pollution induced gradients were minor and not like the “porthole” effect I get with the Edge and its f/7 reducer under these conditions. While the Edge displays minimal focus shift, it was also nice to be using a scope with none.

What’s next other than tuning up PHD2 a little in the backyard? Some dark-site imaging time should el Niño have mercy on me. Accessories? Now that I have resolved to continue with the stock focuser, for a while, anyway, I might consider the SkyWatcher .8x reducer/flattener. However, at this time, I’m pretty happy with the image scale the scope produces at f/7.5. A little faster would be nice, sure, but “a little faster” would mean “a little smaller” in the frame, and 900mm is well suited to the sorts of objects I photograph. If I need more field, there is always one of my smaller APOs, and flattening wise, the Hotech is doing one heck of a job.

Will I miss Betsy sometimes? I will. Mostly because of the wonderful memories. But I still have those memories, and I still have my C11, Bertha, and Zelda, my 10-inch Zhumell Dobsonian, who is a lot easier to handle than Bets ever was. As for the vaunted Hermione Granger? I believe this is the beginning of a beautiful friendship.




This page is powered by Blogger. Isn't yours?


stats counter Website Hit Counters