Sunday, March 16, 2014

 

ISAN 2014 and How Do You Video II


Boomer on her AZ-4
This is actually a semi-twofer, muchachos, since before I get to the main topic, Part Two of the Getting Started in Deep Sky Video article, I’d like to talk a little about ISAN 2014. International Sidewalk Astronomy Night, that is. The evening when amateur astronomers all over the world set up their telescopes in public areas to show off the night sky. ISAN is different from normal public outreach in that we go to the people on this evening rather than having them come to us. 

ISAN has become more and more popular over the last few years, but this year’s edition, scheduled for Saturday evening, March 8, would be extra special. The San Francisco Sidewalk Astronomers, the originators of ISAN, wanted it to be in part a memorial for one of their departed members, famous telescope maker and astronomy popularizer John Dobson, who died on January 15 at age 98.

The Possum Swamp Astronomical Society has been participating in ISAN for five years now, and sure didn't want to miss this one. Not only was this to be a remembrance for a man we revered, ISAN is fun. Being freed from the logistics of setting up a public outreach event allows us to focus on enjoying showing the sky to the public. We just take our scopes to where the public will be and have a good old-fashioned “happening.”

The place for our 2014 ISAN would be the same as in previous years, the Eastern Shore Centre, an open air shopping mall across Mobile Bay from the Swamp. The Centre has a nice central square/fountain area perfect for setting up scopes. There are lights aplenty, sure, but when you’re doing sidewalk astronomy you don’t let light pollution get in the way; you go after the bright stuff. We got the go-ahead from Centre management for this year’s ISAN edition, and kept our fingers and toes crossed regarding the weather forecasts, which were mostly of the “partly cloudy” variety.

Saturday afternoon, the sky was, surprisingly enough, almost solid blue. Time to get the public outreach rig loaded. If you’ve followed this blog long, you know I’ve struggled with “Which scope for the public?” for many a long year. I’ve finally settled (for now) on two. The RV-6 Newtonian for my students/older kids/adults, and a C8 for younguns/general audiences.

The C8 OTA in question, "Boomer," a 1984 model that began life as a Super Polaris C8,  rides on the simplest mount I could find for her, a Synta AZ-4. That’s a one-armed, non-computerized, uber-manual fork. No batteries, no cables, no alignments. Yeah, no goto either, but I’ve found I don’t need that for public outreach. What Mom and Pop and Bud and Sis, want to see is the Moon, a planet or two, and maybe a bright star. At some public events, I’ll show off a bright deep sky object or three, but at the heavily light polluted Eastern Shore Centre, that is purty much a waste of time.

iPhone Moon...
I was feeling right good about our prospects for doing some sidewalk astronomy till the phone rang Saturday afternoon. It was my old buddy Pat Rochford wondering whether I was still planning to do ISAN.  “Huh?” said I. “Cloudy over here,” said Pat. Since it looked so good in the Swamp, I just couldn’t believe we wouldn’t get a few sucker holes, so, come five, Dorothy and I hopped in the 4Runner and made the half-hour trip east to the mall.

Since we were onsite a little early, we spent a few minutes browsing the Barnes and Noble bookstore. Unk admired a couple of graphic novels, but since the suckers didn't have the one I wanted, Batman: Night of Owls, I left empty-handed. It was now time to get set up, and D. and I got everything from the truck to the fountain (which was shut down and dry; apparently, they don’t turn it on till spring) in just two trips: scope, dew shield, mount, tripod, eyepieces, etc., etc.

Looking up, the sky certainly wasn’t pristine, but it was more than good enough to show off Luna, who was shining bravely through a thin veil of clouds. As we were getting Boomer ready to go, we were joined by fellow PSAS member, Taras, and his 10-inch discovery Dobsonian. Not long after, Pat and his 8-inch Dobbie and PSAS President Martin and his Meade LX90 SCT showed up.

How’d it go? Purty smooth. We didn't get many takers at first, but as early diners began leaving the nearby Wintzell’s (local seafood) and California Dreaming (nice chain eatery) restaurants, we were able to give lots of little families looks at the Moon. Did we do anything different this time? Not really. As usual, I operated the scope (“Hold on a second, Coach; let me make sure the Moon is still in there.”) while Dorothy gave out kid-centric literature and stickers courtesy of NASA/JPL.

Unlike all too many Uncle Rod expeditions, there were neither minor hiccups nor major disasters this time. The closest thing to a bummer was that Martin’s LX90’s electronics had died the previous evening, but he was able to press on manually. All told, we probably showed close to 100 folks the Moon and Jupiter on a night that was occasionally mostly cloudy. Best of all? We had one hell of a lot of fun doing it.

Our set-ups with California Dreaming in the background...
By 8 p.m., three things were evident: more clouds and thicker were on the way, it was getting chilly, and most of our “customers,” the little families, were now beginning to drift on home. Sounded like Big Switch time to Unk. I snapped a couple of afocal shots of Luna with my iPhone and called it a night. Dorothy and I packed up Boomer post haste and made a beeline for California Dreaming, where Unk treated himself to a nice rib eye and multiple pints of Blue Moon.

How Do You Video Redux…

Okay…where was we? Oh, yeah…we’d mounted the Mallincam video camera on the telescope, hooked the camera to the computer, and plugged the video output cable into the monitor and DVR. What’s next? Getting goto aligned. I habitually do that with the Xtreme, since the camera’s field is equivalent to that of a medium power eyepiece, and is just about perfect for alignment accuracy. One super cool thing for alignments? Most of the Mallincams will allow you to superimpose a set of crosshairs on the screen. If you are controlling the camera with a computer, that is as simple as checking a box in the control program.

To get started, light off your monitor if you haven’t done so already and apply power to the camera, plugging it into its battery or AC power source. It should be obvious if the monitor is picking up video from the camera; it will go from dark to a gray screen, maybe with a hot pixel or two in evidence. At any rate, when you turn on the camera you should notice a change on the monitor.

If you are using a PC, boot it now and light off the Mallincam control software before you begin goto alignment. If this is the first time you’ve used the software, you need to set it up, which involves telling it which serial com port you will be using to communicate with the camera. To see the com port number the laptop’s USB – serial cable has established, look in Windows Control Panel and Device Manager. In the device “tree,” you will see an entry for “Com and LPT ports.” Click that and the com port number will be revealed.

Original Mallincam software...
When you’ve got that number, go to the “Config” tab in the Mallincam program. If you are not using the original M-cam software, but one of the newer softs like Miloslick, the screen will be different from the one shown and talked about here, but you should have a similar settings screen. If you are using the original software, please note that when you start it up for the first time you will likely get an error telling you the program hasn't picked up a com port. Just acknowledge that and go to Config.

Com port entered in the Config screen, go to the “advanced” tab on the original Mallincam software or a similar camera control screen on the newer program(s). One that allows you to set exposure, gain, and other parameters. 

When you first go to the Advanced tab, you'll see most items are grayed out and a yellow “light”  in the upper left portion of the window is illuminated. There will also be a “safety” timer counting down from 3-minutes. This is to prevent crashes when some camera settings are changed. You can override this safety timer, but you should only do so if you really know what you are doing. Otherwise, wait 3- minutes.

After the timer has run out, you can change settings. At this time, all you will be interested in is short exposure and crosshairs. On the upper left, you’ll see a “Sense up” section. Set the pull-down menu there to 128x. That will give you exposures of approximately 2-seconds, which is enough to show plenty of stars, but not so long as to make star-centering and focusing a pain.

At the bottom left of the window is “Crosshairs.” Check the box there and, assuming the PC is communicating properly with the camera, crosshairs will be drawn on the monitor. You can also choose “crossbox” if you like—which puts a little box at the junction of the crosshairs.

Once you’ve got the above sussed, the rest of the goto alignment is purty much as per normal. You’ll just be observing stars on the monitor rather than in an eyepiece. If this if the first time you’ve used the camera with the scope or scope/reducer combination, your focus will likely be WAY off, but you should still be able to detect a bright alignment star. When you’ve centered the star in the crosshairs of the telescope’s finder, look for a big out of focus disk on the screen. Increase the monitor’s brightness contrast if necessary till you see it. Then, begin adjusting focus until star one is as small as you can get it. When it is, center it in the crosshairs with the scope hand control.

Center however many other alignment stars your scope/mount requires. When the last one is done, take a critical look at focus. At 128x and the default gain of the camera (which will be on the high side), you should see plenty of dimmer stars onscreen. Are they pinpoints? If not, touch up focus. This will get your focus close, but maybe not quite dead on. There are two ways to get precise focus.

Advanced tab...
One is to use an aid like a Bahtinov mask. These focus masks, which go over the front aperture of the telescope, are inexpensive to buy and simple to make. One will produce a series of spikes around a bright star. Adjust focus until these spikes are arranged as per the instructions that came with the mask. When that’s done, focus should be right on. Just remember to remove the mask when you are finished. Don't be like Unk, who invariably forgets that step and starts cussing M13 for looking so fraking funky.

If you don’t want to use a focus mask, salvation comes in the form of a bright globular cluster. Most of the year a good one will be somewhere in the sky, and a glob’s tiny stars are perfect for focusing. Going to one also provides a quick check of the quality of your alignment. When the scope stops and the camera’s exposures “catch up,” center the glob with the hand control if it’s not in the middle of the screen and have a look. A bright Messier should be visible and showing a few stars at 128x, but if it’s on the dim side, up the exposure to 7-seconds.

How you do that will depend on which Mallincam you own. If it is an Xtreme or one of the other cameras that allow computer control of long integrations, just select 7-seconds on the integration control about halfway down the window on the right side. Other cameras may require you to set longer exposures with a wireless remote or via toggle switches on the camera itself. Once you’ve selected 7-seconds, the Mallincam should begin doing repeating 7-second exposures.

At 7-seconds, a good globular will be bursting with stars. What you’ll do is observe those stars, especially the ones close in toward the center. Twitch the focus control a small amount, and then wait for another exposure to complete. Right direction? Need to go the other way? Adjust focus in this fashion until the tiny stars are as sharp as you can get ‘em. Given the small chip/large pixel nature of deep sky video cams, good focus is important for good-looking pictures.

Focus attained, let’s stay on the glob for a bit while we set the camera up. To start, we’ll mess with three adjustments: gain, gamma, and color balance.  “Gain” is much like the ISO setting on a DSLR or other digital camera. It determines the sensitivity of the chip.  The higher the gain, the more sensitive to light the camera will become. Alas, there ain't no such thing as a free lunch (TANSTAAFL), and images will become noisier as gain goes higher. In addition, any light pollution present will be more noticeable as a bright background in the video with higher gain settings. So what should gain be? I am mostly after lots of detail and dim objects, so I habitually run at “6.” My buddies who are more interested in pretty video are typically at 3 or 4.

The bridge of the starship U.S.S. Possum Swamp...
Let’s set gain. In the AGC section on the Advanced tab screen, click “Manual.” Then, enter the gain setting you want. Type the number in the box next to “Manual;” don’t use the up/down controls. When you change gain, the camera’s safety timer will engage. If you use up/down, each click will require a 3-minute wait. Just type in the gain (I suggest 4, 5, or 6 to begin) and you’ll only have to endure one 3-minute time-out.

Next is “gamma,” which is sorta like a brightness adjustment. The control near the top of the screen has two settings, .45 and 1. 1 will give a darker picture, .45 a brighter one. The way I work, with relatively short exposures (28 seconds or less) on dim objects, .45 is best for me. With a brighter object/longer exposure, “1” can make pictures look better. I recommend beginning with .45 until you have a feel for the camera’s settings and how they interact.

Finally, there’s white balance. It’s not overly important except on brighter objects, and especially nebulae. I leave it on “ATW,” automatic white balance. If white balance is “wrong,” pictures can have a pink or blue cast. If colors do not look right, select “Manual” and adjust the red/blue controls.

Don’t have a computer to control your Mallincam? Don’t want one? You can set all these things (except long exposure integrations) with the buttons on the back of the Mallincam or with a wired remote. Mashing the buttons causes menus to appear on the monitor. I don’t like to work without a computer, so I am not an expert on these “OSD” menus, but they've been easy enough for me to use the couple of times I’ve resorted to them. You can find a good description of these menus in this .pdf document from U.S. Mallincam distributor Jack Huerkamp’s website.

You’ll likely find, as I did, that learning to use the Mallincam is a little like learning a musical instrument. There are many settings and they can affect each other. It will take some practice before you begin getting the images you want—but, believe me, you will.

Next? You get to work on the deep sky, of course. You start having fun. You’ll develop your own procedures, but this is how Unk does it. After I am aligned and the basic camera settings are laid in, I fire up SkyTools or Deep Sky Planner on the laptop and have a look at my observing list. I tend to work one constellation at a time rather than jumping around the sky. Once I’ve identified the first object, I’ll look out of the EZ-up to make sure the telescope is clear—of wandering people or other obstructions—and issue the first goto command.

Focus target...
When the scope stops, I’ll usually up the long integration duration to either 14 or 28-seconds. Given my other settings, 14-seconds yields good images even under less than perfect skies, and I will often leave the gain there all night. If I am after the very faintest details and the sky will permit it, I might go to 28-seconds. I will usually only go longer than that if I am after a pretty a picture and need good color saturation and image smoothness.

“How about filters, Unk?” I used to preach against them, since most light pollution reduction filters make longer exposures necessary and shift color balance. Lately, though, I’ve been using a mild filter an Orion Skyglow Astrophotography Filter. It lets me do good work in bright skies and doesn't change the color balance much. I frequently use it when I have to image an object down in the Possum Swamp light dome. The Orion has worked well for me, but it’s a wee bit expensive, and I suspect any mild filter—like  a Lumicon Deep Sky, for example—would do as well.

What else? As I mentioned in the previous installment, I record my video on a DVR since I like to view my results on the big screen TV, and sometimes process video in the computer. The Orion StarShoot DVR’s screen is way small, so I use both a monitor and the recorder. I soon discovered the Mallincams don’t have enough “drive” feed both a monitor and a recorder at the same time using a splitter, however. Video quality suffers. I could use a video amplifier, I reckon, but I owned a cheap solution already, an old composite video switcher left over from the analog video/cable/TV days.

I center the object on screen with the HC if necessary and evaluate it on the monitor. If it doesn't require any changes to exposure or gain or somesuch, I mash the switcher to send video to the DVR. I then push the button on the Orion DVR’s wired remote, which turns on the recorder and begins recording. The StarShoot will record an audio track from its built-in microphone, so I speak my notes into the DVR as I “tape” the video. The Orion also records a time/date display in the upper right hand corner, which often comes in handy. Pretty dadgum slick, all said.

One question I’m sometimes asked has to do with the Mallincams’ ability to output S-VHS video, Super VHS video, which is somewhat higher in quality than normal composite video. My experience is that if you are focused on broadcasting on Night Skies Network or doing heavy computer processing of images, S-VHS can help a little. For just viewing/recording video? Not so much. I never use it.

And then? On to the nextun. If I am moving to a radically different part of the sky, I shine a red light on the scope and watch for cable wrap. With all them wires going to the mount and camera, that is always a distinct possibility. Anyhoo, I just keep going, as I did back in the days of The Herschel Project, recording 50 or 100 or more objects over the course of an evening. That is not too many objects by any means, not when you have the ability to give each one all the time it needs at home on the TV or computer. 

What else is there to the video game? You may occasionally want to improve your videos by processing them with a computer program. Or you may want to make still pictures from ‘em. All that is another long story for another Sunday, muchachos. Now? The night is old, the video is in the can, and Chaos Manor South’s warm den and omnipresent bottle of Rebel Yell are calling.

Nota Bene:  I’m sure all y'all have been watching the big show, but remember to let your non-astronomer friends know about the new Cosmos series hosted by Dr. Neil deGrasse Tyson.  Dorothy and I loved it; it was clear Tyson’s heart was really in it and he did a superb job. Good stuff.

Next Time Unk and the BCH...

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