Sunday, June 28, 2020


#563: “Celestron Screws Up” or “Poor Emma”

It’s a good thing this is a family friendly blog, muchachos, or that title above would have been a lot nastier. As most of y’all know, when it comes to SCTs I’ve always been a Celestron man. Have been for many a long year. Will that change? I don’t know, but I’m plenty put out at them right now. The way I feel at the moment, if I were to buy another SCT it would have a blue tube, or would at least be a used Celestron from before the Synta era.

Until now, the Celestron scopes I’ve owned have just kept on keeping on year after year after year with only the most minor of minor maintenance needed—like occasional cleaning of the inside surface of their corrector plates. So, imagine my surprise and anger when I discovered my beloved Edge 800, Mrs. Emma Peel, had a serious problem thanks to a mistake made at the factory and would require major maintenance after only seven years of ownership.

I’m not sure exactly when Emma’s problem began to make itself known, but I first noticed it many months back:  a shiny inch-wide streak on the inside of the tube running from almost the corrector to almost the primary mirror. I assumed this was from dew that had condensed and slightly discolored the inside surface of the tube. I figured it would eventually disappear and wasn’t a big deal one way or the other.

Then, when I had the scope out the other day getting ready for the start of the New Herschel Project, I noticed the streak was still there and more prominent than ever. I got worried then. I was afraid that, rather than being a stain left by condensation, it might be lubricant from the exterior of the baffle tube or from the focuser that had liquified and run down the tube. That could be a problem, since if the tube got even somewhat hot, that lubricant might begin to vaporize and be deposited on corrector or—worse—primary mirror. I resolved to open Emma up and do some cleaning. I hadn’t cleaned the inside of her corrector since I bought the scope in the spring of 2013, so it was about time for that anyway.

Prepare a good, safe place to pull the corrector.
OK…so time to pull Emma’s corrector. Early one morning, I prepared a place as I always do with plenty of towels for cushioning in the event the lens gets away from me. I also put a folded towel under the corrector assembly so the tube pointed up a little so the corrector plate wouldn't be likely to fall out when the retaining ring was removed. I thought this would be pretty standard stuff. It would certainly not be the first time I’d torn an SCT down to parade rest. A colleague at the university once timed me to see how quickly I could get a corrector plate off and back on on one of the physics department’s scopes (a student had somehow managed to drop an eyepiece cap down the rear port). I set a personal record of seven minutes that time.

I intended to take my time on this one, though. It was somewhat new territory in at least one regard. In the past, Celestron scopes have used little shims around the periphery of the corrector to properly center it—the center position with regard to the primary may not be centered on the corrector mounting on the tube due to mechanical variances. These shims in the past have been little pieces of cork, or, more often, folded paper…pieces of Post-it notes in recent times.

When you put the scope back together, you naturally want to get the corrector properly re-centered in the interests of best optical performance. It was not that hard to use a pencil on the lip of the tube to mark where the shims went, but, yeah, the little pieces of paper deal was kinda fussy and silly. The Edges abandon that for nylon hex screws around the corrector periphery. They thread through the “ring” on the end of the tube, the corrector assembly, and adjust centering. I think it’s a pretty good system. If Celestron isn’t using this on all their tubes, they should be.

I had a standard Celestron OTA here for a review a while back, but li’l old me can’t remember if the nylon screws were used on it or not. Frankly, a lot of things that happened in the year or two before my accident in the late winter of 2019 are strangely fuzzy in my memory now. Go figure. Anyhow, maybe one of you, dear readers, can answer that question for me.

Mark the cetering screw you begin with so you don't lose track.
So, first order of business was backing out those screws half a turn using a 2mm hex wrench. If/when you follow in Unk’s footsteps, mark the first one you loosen so you don’t lose track. That done, the next step in Edge corrector pulling is the same as it ever was.

Firstly, remove the screws that hold the plastic retaining ring against the corrector. Unk put all them screws in a little paper bowl…small screws love to run away and hide on the floor of Unk’s radio shack, which is also his Workshop of the Telescopes. The plastic retaining ring is now accompanied by some foam-like gasket material. Guess that’s OK, though I don’t see much need.

Before proceeding, use a soft pencil or marker to mark the rotational position of the corrector. Celestron no longer engraves a serial number on the corrector periphery, so you can’t use that for indexing anymore. Retainer off and put in a safe place, I removed the scope’s Faststar secondary and put it in a safe place too. “Welp, now all I gotta do is pull the corrector out.

Alas, Mr. Corrector didn’t want to budge. It’s not unusual for correctors to get “welded” to the corrector assembly by the passage of time. A little prying with a jeweler’s screwdriver always frees them, though. However, I could tell immediately that wouldn’t work this time. The feel told me the corrector was still firmly, and I do mean firmly, seated in place. What to do? What I always do in these situations. I stopped, trotted back to the house, made myself another cup of java on the fricking Keurig, and considered the situation.

Somewhat more awake, and equipped with my glasses, I took a second look at the corrector. “Oh, Celestron, you &%$*!!@ idiots!” My now clearer eyes revealed four spots of RTV where the corrector had been glued in place. Why would they do such a thing? Search me. The Nylon screws and the retainer are more than enough to hold the lens in place. And surely, they are aware the corrector will have to be removed sooner rather than later for corrector cleaning or some other reason—like weird streaks of something on the tube interior. What were they thinking?

Once Unk calmed down a little, a boxcutter retrieved from the shack’s bench made short work of that dagnabbed RTV, and the corrector was off and placed in a safe spot. Your old uncle wasn’t quite fuming now. But he would shortly be fuming again in epic proportions. To the tune of one of his classic melt-downs.

Removing the retaining ring.
“Hokay, let’s get that funny-looking streak cleaned up.” I thought I’d probably better start gently with just a damp paper towel—damp with tap water. I scrubbed a little. “Funny. Doesn’t seem to be coming off. Seems to be…getting worse.” One look at the towel told the tale:  It was black with stuff that seemed to have the consistency of lamp black—if you’re old enough to remember what that was. “What the—?!”

What was going on was all too obvious. The paint on the interior of the tube was coming off with gentle scrubbing. The streak hadn’t been some contaminant; it had been the paint failing. Why? Whoever ran the sprayer through the interior of the aluminum tubing to paint it black at the factory in the PRC hadn’t properly cleaned the aluminum first. A little googling later on the freaking Internet soon showed I am not the only person to have experienced this. And that those people I read about who’d reported the problem to Celestron all received the same response, “First we’ve heard of that problem.” Uh-huh.

When Unk recovered from a meltdown wherein he assumed the character of a small, emotionally disturbed child, it was time to consider what to do about Emma. Ship her to Celestron? Nope. Not only was I not exactly in the mood to deal with those suckers, I didn’t want to pay shipping—even if only one way if Celestron agreed to that. And with the Covid 19 virus still running rampant, who knew how long they'd hang onto the scope? I didn’t want to devise a shipping container, either (after years of ownership I didn’t think I needed to hang onto the box the OTA came in any longer). Finally, I didn’t want to subject my telescope to the tender mercies of UPS. 

What I’d have to do was clean as much of the old paint off as possible and repaint the bad area.
First thing to do was mask and glove up and visit Home Depot. A few minutes turned up a small can of high-quality flat black paint. Latex paint. I was loath to use some kind of oil paint with its associated fumes on the scope’s semi-sealed interior. Oh, and a good quality, small brush. Unless I wanted to pull the primary and do a really complete tear down, which I didn’t, brushing would be the only way. Even a small roller would be likely to generate tiny drops of paint and contaminate the primary.

The crux of the problem--after some gentle scrubbing.
The actual job was not as bad as I’d feared. I cleaned off as much paint as I could in the obviously affected area (my damp cloth easily got me down to bare metal).  That done, I brushed on two light coats of paint. The result looked pretty good. Now, brushed-on paint will never be quite as even or pretty looking as a spray job, but maybe you don’t want it to be so even and pretty. A little texture can help reduce scattered light. One thing was sure:  my paint was a lot blacker than what Celestron used, which was more like “medium gray.”

While the paint was drying, I did some more looking around the OTA. “Well…there’s another spot. Oh, and one over there too. It became obvious the entire tube interior had to be repainted. Which I did, exercising care not to get any paint on the primary mirror. It turned out rather well, I think. I’m just hoping I cleaned well enough in the worst spots to get the paint to adhere, and that in the other places the latex will act as a sealer. Time will tell, I reckon. Anyhow, I left the paint to dry overnight before proceeding to reassembly.

Painting done; I cleaned the interior surface of the corrector plate using my time-honored method; one I’ve been using for well over 30 years. What’s required is a box of Kleenex, the unscented and un-lotioned variety; a can of canned air; and a bottle of original (blue) Windex. While some folks worry that something in Windex might somehow harm the optical coatings on a corrector, that has certainly not been the case with any of the many, many telescopes I’ve used it on over the years. Remember, lens coatings are tough, anyway, very tough; they are entirely different from the coatings on first-surface mirrors.

Anyhoo, what I do is blow any dust off the lens’ surface using the canned air. Like Windex, canned air will not hurt your corrector. Do hold the can upright and keep it about 18-inches away. Next, I spritz a Kleenex with a little Windex and swab gently starting at the secondary mount and proceeding outwards, changing tissues every once in a while. Finally, I dry the corrector with fresh, clean tissues. To finish up, I use the canned air to get rid of any lint left by the Kleenex. Again, this method will not hurt your lens, and Windex does a better—far better—job than any lens cleaning fluid I’ve ever used.

Next morning, it was time to get poor Emma back together and off the operating table. No real surprises. The little studs Celestron places around the corrector periphery to engage the dust cap make it kind of a pain to get the retainer back on—you have to bend it gently and slip it into place. That done, retighten the centering screws by the amount you loosened them, replace the screws in the retainer (just snug only), and you are done.

As good as new? I hope so.
As you can see, the girl was back to being her usual photogenic self. And I was pretty sure she’d get a clean bill of health under the stars once I got some of those increasingly rare clear skies. While Tropical Storm Cristobal didn’t go straight over our heads, it came close enough to dump tons of rain.

The denouement, when the evil old clouds finally scudded off for a couple of evenings? I got Emma out for both visual and video observing (which you will read about next week) and she performed just as well as she ever has. She was even still in collimation. The paint job is holding up despite a couple of days under a Telegizmos cover in the heat and humidity of the backyard, so all is well for now and Unk has his fingers and toes crossed.

So, anyhow, what’s my takeaway? I’m still mad at Celestron. I didn’t go out and buy an Edge 800 the day they hit the streets, so this wasn’t a case of early adopter syndrome. And painting the interior of the tube should have been something they could have done successfully no matter what the design of the scope.

But that’s just the way the cookie crumbles. I plan to stop stewing about it and get out under the stars with Mrs. Peel as often as I can in the service of the New Herschel Project. That’s what our magnificent obsession is about, not worrying over the depredations of telescope companies.

Book Plug Department

This time, that plug is for my own book, the 2nd Edition of Choosing and Using a New CAT. I am as happy with this one as I am with anything I've written, and hope you will be too. It is now available from Amazon in both print and Kindle editions. 

Sunday, June 21, 2020


#562: The New NexRemote

Following my re-checkout of my Losmandy GM811G mount after not having used it for way too long, it was time to get to work on the New Herschel Project, muchachos.  But then thunder began to rumble. After several days, I threw in the towel and hauled the scope and my beloved Losmandy inside.

A week later, I thought I might finally get started on the New Project. The scope and camera to do that would be my Celestron Edge 800 SCT, Emma Peel, and the Mallincam Xtreme. Why not the Mallincam Junior Pro or Revolution Imager? The need to get some Herschels under my belt.

I’ve used the Xtreme recently (in the course of writing a Sky & Telescope article) and wouldn’t have to waste time re-familiarizing myself with the camera. I will certainly get to the other two video cameras, since many of you have asked about them. While I’ll turn to visual as well as often as possible, a video camera is usually better suited to the typically hazy suburban deep sky of Possum Swamp in late spring and early summer.

Initially, Thursday night looked fairly good. The Clear Sky Clock, Scope Nights, and the Weather Channel were agreeing it would be the first in a string of relatively passable evenings for observing. But then, despite the Weather Channel still forecasting “clear,” clouds began to fill the sky. I set up the Edge and the Celestron Advanced VX mount in the backyard anyway. What could happen?

Yes, I know I need to get back to the Losmandy mount and get squared away with the Ethernet interface and other software again, but I had a motive for setting up the smaller mount. I’d replaced the AVX mount’s Real Time Clock battery, and, as with the Losmandy, I wanted to make sure the AVX functioned properly after the change. I had little doubt it would be OK, but you never know. Also, frankly, the sky was looking worse than ever. The AVX is easier to lug in and out than the GM811, and I can convince myself to get it into the backyard even if the weather’s looking dicey.

Also, I would also be able to try something new with the AVX. Your benighted old Uncle Rod learned something. Celestron’s CPWI program (“Celestron – Planewave Instruments;” the program was developed in association with Planewave) now works with the Advanced VX mount—it was originally exclusive to the CGX models.

Now, no doubt most of y’all already knew that, but remember, when it comes to astronomy—and more than a few other things—2019 was a lost year for your Uncle. Anyhow, I’d heard a lot about CPWI. It’s sort of like a modern NexRemote, but with model building and star charting added, and I was anxious to try it with my AVX to see if it might fill the same role in the New Project that NexRemote filled in the old.

So, the plan was, the plan was…get started with CPWI. I’d go for the gold with the program to include interfacing it to the Celestron StarSense alignment camera and my Wireless Wingman gamepad (yes, the same Wingman I used with NexRemote for so many years).  If everything was hunky-dory, I might even try connecting SkyTools 3 to CPWI, which appeared to be possible, and start running the Herschel list.

“But Uncle Rod, don’t you know SkyTools4 is out?” I do, Skeezix. I even have a copy of the “Imaging” version, which I reviewed for the Second Edition of Choosing and Using a New CAT. But the imaging version is maybe a little bit of overkill for what I’d be doing, and I do not yet have a copy of SkyTools 4 Visual, so it would be good, old ST3, which saw me through the original Herschel Project.

Set up Thursday afternoon was OK, if not exactly a joy—it’s already awfully warm here. I knew if I waited till the cool of the evening, though, I might lose the will to mess with all the video gear and the computer, so I got on it. The AVX and the SCT are not too bad, and I was able to set everything up without incident. Well, only one. I started to pick up a heavy equipment case with my “bad” arm and it swiftly told me not to do that.

So, it finally got dark Thursday night just as Rod’s favorite 10-meter net (The Lockdown Fun Net, Thursdays, 1900L, 0000Z, 28.420 MHz) was wrapping up after a rollicking session that lasted far longer than usual…10-meters was “open” and we had W2s, W3s, W8s and more check-in for what is usually a local net here in Four Land. Walking out of the shack, I saw what I pretty much expected to see:  brighter stars winking in and out as bands of clouds and haze began to move in on what had been a clear sky in the afternoon. Naturally.

Typical Possum Swamp spring sky.
The sky wasn’t good enough to even think about firing up the Mallincam, not even close. Nevertheless, I uncovered Mrs. Peel. If I couldn’t do anything else, I’d at least polar align the Advanced VX using Sharpcap and my QHY guide cam. While a dead-on polar alignment isn’t necessary for video, it can make the stars look better in 30 second exposures. Also, Sharpcap makes it easy, so “Why not?”

What was it like coming back to polar alignment on the Advanced VX from the Losmandy? Like most other Chinese mounts, the AVX uses bolts for altitude and azimuth adjustment. Good thing is these bolts at least have nice, large handles as compared to the old CG5. Polar aligning the AVX is more “twitchy,” but it wasn’t hard for me to get the error under 15-arc seconds. That done, I covered the scope up and went inside to watch the 100th episode of the exceedingly silly Ghost Adventures on cable TV.

Friday evening found me hoping for at least sucker holes as darkness arrived in Hickory Ridge. How’d it go? I guess you could say it was a classic Unk Rod evening. Oh, it started out promisingly enough. The sky wasn’t exactly clear, but most of it was OK. A check of date and time in the NexStar HC said ever’thing was cool with the RTC battery. The CPWI software connected to the AVX through the hand controller without complaint. OK. Fine Business. Guess I’ll start an alignment, a StarSense alignment.

I mashed the appropriate button, but instead of starting the alignment, CPWI asked me if I wanted to calibrate the StarSense. I wasn’t sure if I did nor not. However, I hadn’t used it in a pretty good while and this was my first time to use it with CPWI, so I thought that might be a good idea. The program instructed me to slew to a bright star, and even highlighted some suggestions on the star chart. OK. Well, how about Arcturus. I clicked goto, and off the mount went.

Despite a very good polar alignment, when the mount stopped, the star was not in the field of the Mallincam. Alrighty then, I left the deck for the yard and peered through Mrs. Peel’s Rigel Quick Finder. The star was reasonably close, but no cigar. A degree or two away, mebbe. I’d just center it up and… Wait. How would I center it? You cannot use the HC with CPWI interfaced to the mount. “Oh, yeah, a joystick just like in the NexRemote days.” I’d thought that might be necessary, and had hauled out the old Wireless Wingman.

I went to the gamepad set up screen where I was told to press “start” on the Wingman. I did. Repeatedly. What happened? Nuttin’ honey. So, I spent the next half hour trying everything I could think of to make the software connect to that old game controller. Nothing worked. What would I do? I recalled I had a wired Xbox controller in the house. I went in and got it, plugged it into the USB hub, and the computer made its bing-bong noise and happily set it up.

OK. Let’s see what CPWI thinks of this one. It liked the Xbox controller just fine, picking it up immediately and sending me to a configuration screen. OK, I’ll just take this out to the scope and center that dad-blasted Arcturus. Sorry, Unk. The cord on the joystick was about 3-feet too short. Luckily, one of my few remaining braincells fired and I recalled I had a 6-foot USB extension cable. I even knew where it was. Fetched it, plugged it between Xbox controller and PC, and had enough slack to get my eye behind the Quick Finder. I centered that pesky star well enough that it was visible on the Mallincam display, and went back to the PC and did the fine centering with the Mallincam’s crosshair overlay and CPWI’s virtual HC.

The program seemed right happy then. Said it had done a plate solve and yadda-yadda-yadda, did I want to start an automatic StarSense alignment? I darned sure did after wasting so much time. Ha! Clouds were pouring in from the west now, impelling me to throw the Big Switch.

So, yeah, it was a prototypal Unk Rod evening. But as with most of those, I learned some stuff about CPWI—mostly how to navigate the new software—and now felt fairly comfortable with it. What next? Well, Saturday evening was slated to be about the same as Friday. If I could just get one freaking H-400 in the can, your old Uncle would be a happy camper.

The sky was clearing nicely late Friday afternoon, but then, as I was out for my evening stroll around Hickory Ridge, my phone beeped with a notification from the cotton-picking Weather Channel. The sky was pretty and blue, but this missive insisted there were severe thunderstorms just to the west. Nevertheless, I thought I’d be OK; it looked like the storms would slide past us to the northwest. 

About half way through watching the latest episode of Harley Quinn’s show, I figgered I’d better check on the scope and all (I’d uncovered Mrs. Peel and had everything ready to go on the deck—computer, video display, etc.). One look at the sky, and I covered the scope up in a hurry and moved the rest of the stuff inside. It was just getting dark, but it was still light enough for Unk to see threatening clouds blowing in from the West. There was a strong breeze stirring and a feel in the air that portended “b-a-d weather coming.”

There was bad weather coming, culminating in a forebodingly early Tropical Storm, Cristobal, in advance of which, I naturally moved mount and telescope inside. The storm was minor in nature, but it did bring wind gusts of 30mph and dump about 6-inches of rain, so it was good Mrs. Peel was safe and snug inside.

Following the storm, the weather improved slowly. It wasn’t good enough for me to get Emma and the Xtreme out, but it was good enough for me to get my old friend, my ETX125, Charity Hope Valentine, out of her case and working again (which you read about last week). That night with Charity Hope Valentine became Night One of the New Project if just barely. I observed a grand total of exactly one object. After that, I sat and waited for better conditions, which it appeared might come the following Tuesday.

CPWI's initial display.
First task once the stars winked on Tuesday night was to see if I could really get CPWI pointing at objects and, just as importantly, interfaced to SkyTools 3. If either thing didn’t work well or reliably, I’d just go back to using the (StarSense) hand control with SkyTools and/or Stellarium. Both things had to work if CPWI were to be part of the New Herschel Project, if it were to be the new NexRemote.

Alrighty, then. I decided to start out with just an eyepiece. Leaving the Xtreme out of the picture initially would allow me to focus on CPWI. So, my good old 13mm Ethos went into the William Optics SCT diagonal I’d screwed onto (ahem) Emma’s rear. That would yield 154x, and despite the eyepiece’s large field would give CPWI’s pointing prowess a good test (I left the reducer off so the scope would be working at f/10).

Polar alignment complete and mount powered on, I started CPWI on the laptop and was presented by the display you see above. Next step was getting the mount talking to the software by choosing the connection type under the Connection menu on the left toolbar. There are three possibilities:  Hand Controller, Wi-Fi, or USB. Most of us will use Hand Controller, which means you’ve got a Celestron serial cable (or a USB cable) plugged into the base of the HC. If you’ve got a Celestron Evolution scope or one of their wi-fi dongles on another Celestron rig, you’ll use “Wi-Fi.” Finally, Celestron’s CGX German mounts allow you to use a USB cable plugged directly into a USB port on the mount.

Select your alignment method.
Once successfully connected, you’ll be asked to verify time and location. I’d already done that during my previous CPWI outing, so it was on to telescope alignment. Next you’re presented with the goto alignment selection window. There are two main choices: CPWI alignment, where you add points to a model by centering stars; or an alignment done with the StarSense automatic alignment camera.

If you choose to do a “manual” alignment, a CPWI alignment, the program will select four points (stars) it believes are good alignment choices, and you’ll center and accept them much as you would with a hand control. The difference with CPWI is you can continue adding as many points to the sky model as desired.

Unk, lazy sort he is, naturally had the StarSense hooked to the mount. Since I’d calibrated it on a star on my previous night out with the software, all I had to do was start the normal StarSense four-star-field automatic alignment. That wasn’t much different than it would have been with the hand control except I could read what the camera was doing on the laptop screen instead of having to squint at a tiny hand control display. After about the same amount of time it would have taken the hand control, CPWI announced we were aligned.

If, unlike Unk, you have not already polar aligned the mount, you may do an AllStar Polar Alignment with the program following either type of goto alignment. Let me add that many of the usual hand control features like PPEC, parking, changing slew rates, etc. can be done with CPWI. Which is a good thing, since as mentioned earlier you cannot use your hand control at the same time you are using the program. It is in a “boot loader” mode and utterly unresponsive.

“Hokay. Let’s see if CPWI aligned anything.” Peering around the patio umbrella on the deck and up at the sky showed bright Arcturus riding high. I located the sparkler on CPWI’s star map, clicked on it, clicked “slew,” and the mount and Mrs. Peel headed for the star just as they would have done with Stellarium or any other program. Trotted out to the scope, and there was Arcturus sitting pretty in the field center.

Ready to begin a StarSense alignment.
How about a deep sky object? M3 was nearly at zenith, and I figgered that would be a good test of the program’s goto abilities—just about any goto system can have trouble with objects near straight overhead.  Instead of locating the globular cluster on the map, I used the program’s search feature, which worked well, and soon had the scope heading to M3. When the AVX stopped, M3 was staring back at me in the eyepiece. It was a little off-center, however, so I nudged it to the middle of the 13mm.

How did I do that nudging? Well, I could have had the laptop set up next to the scope and used the program’s onscreen direction buttons, but that wouldn’t have been very convenient. Instead, I used the Xbox gamepad. It took a little fumbling to get it going again, but when I did, it worked just ducky for the rest of the evening. If you are going to be using CPWI without a StarSense, a gamepad is vital because you’ll be centering numerous stars to do your goto alignment. A wireless PC or Xbox gamepad would be best. Me? Since I’m mainly gonna be sitting at the PC and viewing images on a video screen, my wired controller is more than adequate.

I sent the scope to quite a few other targets, no problem. Well, other than most looked pretty putrid in the haze. All that remained now was to get SkyTools 3 running with CPWI, attach the Mallincam to the scope, and knock off some Herschels.

After using SkyTools with NexRemote for so many years, the concept of using it with CPWI was easy to understand:  I’d connect SkyTools to the scope through the program, not directly. The procedure for doing that is different than with NexRemote, but the result is the same. Instead of establishing a virtual port for SkyTools with NexRemote, what you do with this modern software is start up SkyTools’ Realtime (its goto module) and use the ASCOM Chooser to select “CPWI” as the telescope.

As with the Gamepad, it took a little of Unk’s patented fooling around to get it going, but once I did, SkyTools 3 worked faultlessly with CPWI. I’d click on an object on my SkyTools observing list, SkyTools would announce “Slewing telescope!” (in its sexy British-accented female voice), and we’d go to the object. That was all there was to it.

SkyTools 3 with "always on top" CPWI hand control.
Next? Knocking off some Herschels. Unfortunately, I’d burned most of the evening getting the Herschel Project software squared away. At this point in the late spring, it doesn’t get dark until nine—not even dark enough to do a polar alignment. And a look at my watch showed the time was now passing two. Part of me wanted to get the Xtreme on the scope anyway, but I demurred. I was hoping the next night would be at least as good as this one had been and pulled that cursed Big Switch.

Summing up? I am not feeling particularly charitable toward Celestron at the moment—you will find out why next week—but regarding this (free) software, I gotta say they done good. It is not perfect, but it certainly workable. Most of the improvements that are needed concern the star map (for example, why no constellation labels?). I do understand most of the program’s development, which has been slow, has had to be concerned with getting alignment and connectivity issues resolved. Anyhoo, now they need to spiff up the star map. Also, a little more gamepad functionality would be nice. As is, all you can do is move the telescope (fast or slow) with it.

At any rate, I am convinced CPWI and SkyTools 3 (or Deep Sky Planner, which I'll check out with CPWI next time) are what I will use initially for the New Herschel Project—when I use the Celestron mount, anyway. CPWI has got a feel a lot like good, old NexRemote. Enough of a feel that I’m not missing my favorite piece of astronomy software quite as much as I was, muchachos.

Sunday, June 14, 2020


#561: Fifteen Years After the Honeymoon or "The New Herschel Project: 1 Down, 399 to Go"

If you’ve been following the AstroBlog for a while, I don’t have to tell you who Charity Hope Valentine is. If you haven’t? She’s my little Meade ETX125PE Maksutov Cassegrain.  More than a few ETX fanciers—yes, there are still some out there in addition to your old Uncle Rod—have asked me how 15-year-old Charity is doing. The answer has been, “I don’t know, muchachos, I don’t know.” She hadn’t been out of her case in a couple of years. Could be three. Possibly four. At his advanced age, Unk’s months and years tend to fly by and get all jumbled up together. 2016, for example, seems like just yesterday. Nay, just hours ago.

My little girlfriend has, on balance, always been a Good Telescope. I’ll be the first to say she can be a slightly neurotic handful like her namesake, but she usually cooperates with your old Uncle. Charity has starred in more than a few AstroBlog articles, and if you’d like to learn more about her, click here, here, and here. But the above pretty much sums up our relationship over the years. 

Anyhow, it had been a while since I’d even thought much about the 5-inch Maksutov Cassegrain. But seeing as how I was looking around for something to do astronomy-wise with the New Herschel Project stopped in its tracks by clouds, I thought I’d get Charity out. I’d need to replace her battery, and would do any other maintenance she required. “Battery?” Yes, Charity is one of the last of the original breed of ETXes, the non-Ningbo Sunny ETXes if’n you know what I mean. She’s a PE, and she has an LNT.

“Wut?” The PE (Premier Edition) ETXes were different from earlier models in that they featured pretty—some would say garish—silk screened tubes and the aforementioned LNT finders. That stands for “Level North Technology.” A PE was like a GPS scope without the GPS. All you had to do was set the scope in a simple home position and turn it on. Charity and her sisters would then do a little dance, finding north and level, and would head to the first of two alignment stars, which you'd center. That was it. For it to be practical, of course, you had to have a real time clock battery to keep time/date current when the ETX was powered off.

The Girl Still has Her Good Looks
The system worked well. You didn’t even have to enter your position into the Autostar unless you moved at least 60-miles from your previous location. According to Meade, the LNT battery would be good for “five years.” That was awfully optimistic. One year or a bit more being as long as the scope’s 2032 button cell has ever lasted for me. That wouldn’t be so bad if Meade hadn’t made it so devilishly difficult to change the battery on the initial PEs. Not only is the battery down deep in the scope's red dot finder's guts, the finder uses a big plastic lens that's just begging to be snapped off in the process of replacing said battery.

Meade soon reworked the LNT finder, adding an easy (or at least easier) to access battery compartment and a lens for the red dot finder part of the LNT that would be less likely to be accidentally snapped off. Charity, however, is an original. Nevertheless, I’ve managed to keep Charity’s finder lens intact and battery changed out these 15 years. 

At any rate, I recalled replacing Charity’s RTC battery required disassembling the LNT finder, unscrewing a pair of bolts (the finder alignment bolts), and removing two associated springs, one of which is insanely difficult to replace when you are done. Naturally, these springs want nothing better than to fly off and hide on the floor. But maybe I wouldn’t have to do anything about the 2032. Maybe after “just” a couple of years of disuse, the battery would still be good. I was doubtful, however, and hunted up one of the button cells in the kitchen junk drawer where such things reside.

I pulled Charity from her case. Despite the passage of all the long years, she’s maintained her girlish good looks. I’ve always tried to take good care of my friend; she’s deserved that in thanks for the years of joy she’s brought me. But would she wake up when I turned her o-n/o-f-f switch to o-n? After who knew how many trips around the Sun?

That big lens just begs to be snapped off.
I plugged in the Autostar, plugged up a jumpstart battery, flipped the switch and… Sweet Charity emitted the friendly beep that means, “Hi Rod! I missed you!” and displayed the good, old “Welcome to A U T O S T A R” on her red LED screen. I was at least relieved she'd awoken without complaint. But how about that battery? I mashed "Mode" a few times to get to time and date and…uh-oh. “07 July 2016.” Had it really been that long since I’d (ahem) turned on Charity Hope Valentine? It didn’t seem possible, but maybe. The time was, no surprise, off by hours.

So, there’d have to be a battery swap. I still have Charity’s manual, of course, and reviewed the instructions on that task. OK, remove the top adjustment bolt. Check. Remove the side adjustment bolt. Check. Gently lift the top of the LNT housing (there’s a wire connecting top to bottom). Check. Don’t lose the two springs associated with the bolts you just removed. Well, the horizontal spring was no problem, but, as I had feared, the vertical, smaller spring went flying to the floor of Unk’s (radio) shack. He spent the next 15-minutes crawling around on said floor with a Maglite before turning up the frickin-frackin thing.

“Well, alrighty then,” Unk said (actually he said some colorful words in the course of locating the spring and replacing it during reassembly). Next step was removing and replacing the button cell itself, which was no problem, it being held in the typical spring-type battery holder. What was a problem was reassembling the LNT. Lining up the vertical spring, passing the bolt through it, and tightening the bolt was not difficult; the other bolt and spring were where the problem lay and has always lain.

Alas, Meade’s instructions for replacing the horizontal spring were insane: “Tighten the vertical bolt until it is firm.” If you do that, there is very little space between the side of the bottom half of the LNT and the side of the top. You have to squeeze the spring between those sides, aligning it with the holes, and inserting and threading-in the horizonal bolt. It was clear that would never work. Not in a million years. What did work was threading the vertical bolt in just a few threads. That left enough space between bottom side and the top side for me to squeeze the spring into place. I managed to use a solder tool to nudge it around to get the holes lined up, and got that hellish bolt screwed in.

Surgery begun...
Next on the agenda would be recalibrating my girl’s sensors—one of the two requirements following a battery change, the other being “drive training.” Sensor alignment would require the star Polaris. There was no doubt in my (once) military mind that this would not be a Herschel Project night—I’d disassembled Mrs. Peel and moved her back inside to wait for a better stretch of weather. But maybe I could at least get Charity dialed in on the North Star?

It turned out I’d have to wait a while before I could even get the girl into the backyard. We had the perfect storm from an observer’s point of view: waxing moon, cloudy skies night after night, and, finally, Tropical Storm Cristóbal hit the coast dumping torrential rain on Unk’s vaunted backyard.

Anyhow, last Thursday dawned to drier and slightly cooler weather, which is common in the wake of a tropical storm. It looked so nice, almost fall-like, that I began to wonder if I should squander the night on “just” a 5-inch MCT and eyepieces. Alas, as the day wore on, those darned old white, fluffy things began to scud across the sky. I could scarcely believe it. Actually, that’s wrong. The way the weather’s been the last couple of years, that’s exactly what I have come to expect. I decided to stick with Charity and delay placing even her in the backyard until close to sundown.

And…the clouds just kept pouring in, flowing from (strangely for here) northeast to southwest. I had little hope, but at about 9 pm clouds had skittered off to the extent I thought I might get something done. The sky was still hazy, though, very hazy. While I could make out the Dipper/Plough, only the two “end” bowl stars of Ursa Minor were apparent. Whatever. At least I’d get the Calibrate Sensors business completed.

This is how the sky looked--until Sundown.
What that does is inform the mount’s computer of the difference between true north and magnetic north for the scope's current location. There’s really not much to it for the user. I put Charity in her home position (rotated counterclockwise to her hard stop), locked the azimuth lock, and started the procedure. The scope points to true north as best it can given the readings from its built-in electronic compass; then you are instructed (by the Autostar) to center Polaris and press Enter. Our magnetic deviation is small here, so just a little slewing put the North Star in the crosshairs and I was finished.

Next up, I figured I’d better do some Drive Training, the purpose of which is to let the ETX computer know the magnitude of backlash in the mount's gears. That is vital for good goto pointing. After years of experience, what I’ve determined is it’s better, for some reason, to use a terrestrial object like a distant streetlight than a star. You’d think Polaris would be just the thing, but it doesn’t seem to be. Unfortunately, there's not a good terrestrial target visible from my backyard, so I just used Polaris, which worked OK.

As with Calibrate Sensors, there’s not much to Drive Training. The Autostar tells you to center your target, you do that and press “Enter,” it slews away from target target and tells you to re-center it (the Autostar even shows you which direction key to mash) and you do that, and press Enter again. Repeat the procedure for both azimuth and altitude and you are done. In my experience, drive training needs to be accomplished periodically. So, when Charity begins missing targets, I immediately do a quick re-train.

Note, as with some other goto systems, certain targets are just hard for Charity's Autostar--mostly those directly or near directly overhead. Because of the construction of the ETX's fork, it's hard to access the focus knob when the scope is pointed near zenith, anyway. So, all things considered, as with big Dobs, it's best just to avoid Dobson's Hole with an ETX.

The sky really was looking yucky now. Not so much cloudy anymore as just very hazy. However, I thought if I could get an object or two in the can, so to speak, that would put me ahead of the game. I also wanted to see if Charity was still her old self after so long a layoff.

In her salad days.
Yes, the haze was bad, the seeing was bad, and clouds were still scudding through. But that is exactly what I used to call a “Sweet Charity night.” Her good contrast despite a rather sizable central obstruction (do NOT tell her I said that) gives her a leg up under conditions like these.  I’ve often been surprised at what the girl can pull out of some fairly nasty conditions.

On this night? Not so much. Messier 3 looked OK—at 150x a fair number of stars were resolved around its periphery—but just OK. Not even really “fair.”  “Well, let’s knock off one Herschel 400 object, anyhow. M82 oughta show something.”

Indeed, Ursa Major’s Cigar Galaxy did show something; just not much. When Charity stopped slewing and the weasels-with-tuberculosis sounds that accompany that stopped, I wondered if she’s missed the Cigar. However, a little bit of staring and reducing power to 75x showed a filmy something centered in the field. A little more looking with averted vision turned up the galaxy. I could cross M82 off the list, but that’s all I could do. There were no dark lanes visible, and even the basic shape of this “disturbed” galaxy came and went.

Also, the bugs were biting. When I’d masked up and visited Publix the previous Tuesday, they didn’t have any of the replacement candles and repellent pads for the Off mosquito lantern I use to keep the biters at bay (much less expensive than Thermacell refills). So, I thought the best course was to throw the big switch, cover Miss Valentine, and perhaps devote one more night to her.

Friday was supposed to be better, but, like Thursday, while it started out clear and crisp and beautiful, as soon as darkness came the sky flooded with clouds. So that was that. I disassembled Miss Valentine and returned her to her case--I hope for a shorter stay than last time. I didn’t feel like I could devote any more of our increasingly few observing hours to my ETX girlfriend no matter how much I love her. Next up will be my Edge 800 and Mallincam and we’ll see if we can really knock off some New Herschel objects.

Nota Bene:  Friends, while Charity was mostly in good shape after all that downtime, I noticed the insulation on her Autostar hand control cable is gone in several places. I’ll definitely need to replace it before our next outing. Unfortunately, a bit of googling hasn’t turned up a source for a good replacement. Can any of y’all help?

Book Plug Department

I’m gobsmacked at a new book that’s just crossed my desk, Thomas Fowler’s The View Through Your Telescope. It is subtitled And How to Make it Better. And that is just what it can do, muchachos. I haven’t had time to really dig into it yet, but I can tell you already this is just the sort of book a lot of us, and especially imagers (but not just imagers), have been looking for. It is somewhat technical in places, but that’s also just what many of us have been looking for. Go get it, muchachos. Expect a full review soon.

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