Uncle Rod's Astro Blog

As most of you know, astronomical video imaging, “deep sky video,” is my bag. While I’ve mostly been doing DSLR/CCD astrophotography the last year or so, I’ve never lost my love for video.

A sensitive vid-cam makes it so easy to go incredibly deep. With my humble C11 and CGEM and Mallincam, for example, capturing 17^th magnitude and dimmer Quasars was nothing. The only limitation seemed to be me becoming bored with one more insanely distant bluish, star-like object. I haven’t just practiced video, either. I’ve preached about the “video revolution” here, in the pages of Sky & Telescope, and on our observing fields.

So why isn’t every deep sky crazy amateur astronomer using video cameras? There are a couple of reasons. First, some people just like looking through an eyepiece. Video delivers faint objects in such short exposures that it almost seems like you are observing in real time, but for some it still ain’t the same as eye and eyepiece.

The nay-sayers are not necessarily a majority, however. There are plenty of amateurs who would love to see detail in the brighter deep sky objects from the light-polluted backyard, capture dim and challenging DSOs from darker sites, and use video in public outreach. Unfortunately, there’s been one big thing preventing them from doing all that: m-o-n-e-y. For the longest time, one thousand dollars was the video admission price, with close to two-thousand being more realistic  for a capable camera.

Those economics began to change a few years ago with the release of bargain oriented astro-vidcams, first in the 500 dollar range, and, shortly thereafter, in the 100 – 150 bracket. Much of the growth in bargain astro-video can be attributed to one camera, the LN300. This 1/3-inch chip cam from China (natch) is based on a design (probably) developed by Samsung, and after it caught the eye of astro-video experimenters, it was soon being modified and sold for astronomy by several vendors.

So, which LN300 do you choose? Some variants of the basic camera have firmware that makes it easier to achieve color in some modes, but all work very well for astronomy. They are amazingly sensitive and display little of the dreaded “amp glow,” that brightening of the corner of the frame, that plagues some deep sky cameras. The LN300s also offer other features useful in astronomy, including the ability to stack up to 5 image frames internally. That produces smoother and denser images. The maximum exposure of the camera is about 20-seconds, but thanks to stacking, and, most of all, the sensitivity of these little wonders, that is not a handicap.

Which “brand” of LN300, then? Heretofore, my only advice in that regard was “Get one from an astronomy dealer.” The main reason for that was camera control. The stock camera is operated with tiny buttons on its rear. Those allow you to set exposure and other things, but having to go out to the scope to push minuscule buttons in the dark is not the way I like to roll. I prefer to sit under an EZ-Up canopy at a star party or on my deck at home and operate the camera from there. Luckily, astro-merchants supply LN300s with wired remotes and/or software for controlling ting the camera from a laptop. So, I told budding astrovideographers, to just get a camera like that from an astronomy-oriented dealer. Any dealer.

That’s changed, however, because of what I think is an incredibly neat little kit and a great buy being offered by Orange County Telescope, the Revolution Imager. What it is is a case with everything you need to get started shooting astronomy video inside:  an LN300, a battery powered 7-inch LCD monitor, a wired remote for the camera, a focal reducer, an IR block filter, a battery to power camera and monitor, and all required cables. Darned neat, I think. While video, like any other sort of astrophotography, can’t be made “turnkey”—it requires practice and learning—having everything you need and complete instructions for hooking it all up and getting started makes that learning a heck of a lot easier.

Anyhow, when Orange County’s proprietor, Mike Fowler, asked if I’d like to try the Revolution, I naturally said yes. At $299.99, I thought the Revolution could be a major breakthrough. No need to spend about that much on just a focal reducer and a monitor. No scratching your head as to how to make it all work together. The more I ruminated on it, the more I thought this could be the coming of that video astronomy revolution I’d been predicting for a long time.

When the Revolution arrived, I was even more impressed than I’d been just looking at it on the website and reading its specs. You really do get a lot of stuff nearly packed and ready to go. Go where? In my case, the kit went was into the 4Runner for our recent trip to the Deep South Regional Star Gaze where I hoped to give the set a good workout.

In astronomy, you don’t always get what you want. You sometimes get what you need, but you do not always get what you want. While I got the DSLR pictures I needed for a magazine article I was working on, I barely got to try the Revolution. A slow-moving front began to pass through on Thursday evening, which I’d declared was to be “the night of the Revolution.” I was able to set the system up, though, and at least give it a short preliminary test.

Revolution hand control...

Actually, I’d had the good sense to set up the Revolution at home before we left for DSRSG. One thing that is different about the kit is that you’ve got a rather complicated looking wiring harness that connects all the components, camera, monitor, and battery, together. Luckily, the good folks at OCT have posted a set of excellent instructional videos on the Revolution website. I watched those, which soon made clear how everything was supposed to go together. I also printed out the basic camera setting instructions, though I was fairly familiar with how to work an LN300.

My setup, which you see pictured below, is actually a little more complicated that what many of you will deal with. Since, as above, I like to sit under an EZ-Up and operate the scope, I connected a long extension cable between camera and wiring harness. The cable in the kit is long enough to allow you to set up the monitor a few feet from the telescope, but I wanted longer than that and had a combo power/video cable at hand that I use with other cameras. I see that OCT now offers a 25-foot extension cable (and some other cool accessories as well) as an inexpensive option, and that is a good thing.

Some users may be happy having the monitor mounted on the scope, maybe the upper cage of a Dobsonian, however, and will not need an extension cable. The Revolution kit includes a tilt-swivel monitor mount with an adhesive backed base that is perfect for attaching the display to scope tubes or mountings. Instead, I pasted it to a plastic clipboard, which provides a steady, sturdy mounting for the monitor.

In addition to an extension cable, I hooked up my Orion DVR. I like to preserve my deep sky videos, and this tiny digital video recorder works very well for that purpose. I simply ran the output of the camera to an old analog switch box left over from the non-digital cable TV days and used that to select monitor or recorder as desired.

I ran into only two problems on this first night:  clouds and tracking. I had the camera mounted on my “secondary” scope, a C8 and CG5 combo I’d bought along to the star party to sell, and that telescope was only roughly polar aligned. Oh, I knew that for good looking stars even with short video exposures you need decent polar alignment, but the appearance of the skies told me I’d better hurry and I dispensed with the AllStar polar alignment procedure in the interest of getting something before we were socked in. In the end, I had a little over an hour (including some waits for clouds to pass) to see what the Revolution would do.

My impressions? Most of all, that this is such a sensitive little camera. Didn’t matter what I turned the C8 to, the camera snapped it up. The Crescent Nebula, the legendarily dim NGC 6888 in Cygnus? No sweat. Both loops of the Veil? Done. M74? There were the spiral arms right on the monitor. What was really cool was setting the camera to stack images. While I’d used LN300s a couple of times before, that was not a feature I’d played with. It was neat to watch the supposedly dim Crescent slowly develop on the screen like a photographic print in Dektol (now I am dating myself).

How did the system work otherwise? Just fine, thank you. While I wouldn’t call the monitor high resolution, it looked at least as good as the screen of the portable DVD player I used as a display for years and which carried me all the way through the Herschel Project. The only thing I didn’t try was the included focal reducer. I’ve got a Meade f/3.3 reducer for the C8, and while the .5x Revolution reducer would no doubt have been fine, when dealing with an f/10 8-inch, the more focal reduction you can achieve, the better.

The kit’s lithium ion battery, by the way, had no problem powering camera and monitor for an hour and a half, and I suspect would have been fine for several hours. Not having to worry about an AC source or carrying around a big jumpstart battery would be an asset for public outreach, and I believe the cell would easily deliver enough juice for the average public session.

While I didn’t have time to really play with camera settings, I was nevertheless impressed with my results. The picture of NGC 6888 here is, by the way, just a single frame grab from the video. No additional processing was done other than minor level adjustments. Believe me, the object looked even better “live.”

I continued working until the last photons of the Crescent were extinguished by clouds and building ground fog. I was a little disappointed, but since I had a trip to the Chiefland Star Party scheduled for the following week, and hoped to get plenty of hours with the Revolution down Chiefland Way, I didn’t feel too bad.

Crescent from DSRSG..

Alas, once again things didn’t go exactly the way I’d planned. The basic problem at CSP was that, as I reported a couple of weeks ago, I could only get a motel room for one night, which limited me to two days. After driving 350 miles, I was willing to put up with porta-potties and open air showers for one day/night, but no longer. I did give the camera a try in the waning hours of Friday evening, but it had developed an intermittent fault in its power cable and I threw in the towel and went visual, which was fine, if not what I’d hoped for.

One of the benefits of buying the Revolution instead of an off the shelf camera (which will likely have a substandard built-in IR block filter installed)  from eBay or somewheres is SUPPORT. Mike fixed the power cable problem quickly and he and his colleagues took immediate steps to ensure this would not happen to anybody else. No, $300.00 is not an awful lot of money, but it is some money, and it sure is nice to have support from people who know astronomy backwards and forwards if there’s a problem.

Back home, clouds kept me indoors for a few days, and shortly thereafter the Moon was back in the sky. I was anxious to get the new camera outside again; the encouraging results I’d gotten at Deep South had just whetted my appetite. But I also wanted to give it as much of a chance as possible to show what it could do from my backyard, which has a zenith limiting magnitude value of about 5 or so on a good night. I bided my time.Finally there came an evening which, while not perfect due to heavy haze that was amplifying the light pollution, was good enough.

One of the beauties of video is what it can do from the backyard. Video allows you to see so much more from the back-forty than you can visually. At the club dark site, a 12-inch scope will give you at least a dim glimpse of the spiral arms of M74, for example, but in the backyard a 20-inch likely won’t show them. Video will. A good deep sky video camera will, anyway. Would the Revolution, though?

With Sol sinking, I set about getting ready to video. After connecting up the Rev a few times, I was now clear on what plugs into what on the cable harness, but it might be helpful if you taped little labels to the connectors to help in the beginning: “battery,” “camera,” video monitor,” etc. You'll get the idea soon enough, however. Especially if you take the time to watch the aforementioned excellent videos.

I got all the cables connected to the harness and then mounted the camera on the C8’s rear port with the all important f/3.3 reducer. If you are using the included .5 reducer instead, that screws onto the 1.25-inch camera nosepiece, and the whole thing is inserted into the SCT’s visual back. If you are using another style of telescope, a reflector or a refractor perhaps, you will do the same. Screw the included reducer onto the nosepiece and insert the whole thing into your focuser (be aware some Newtonians will have trouble coming to focus with any camera).

Backyard Dumbbell...

What did I do then? Next up was goto alignment. Video cameras have small chips, so a goto mount is pretty much mandatory unless you want to spend all night getting a few objects onto that tiny sensor. When the VX mount was goto aligned, I used the guidance of the instructions that came with the camera (and can also be printed off the website) to set exposure to the equivalent of ½ second, “x33” in LN300 speak. That provided enough oomph to show even badly out of focus alignment stars as big donuts and also enabled me to get focus at least roughly “in.” Remember, the reducer will have changed the focus point of your scope radically from where it probably is with an eyepiece.

How did I get to a menu to adjust exposure? That’s easy with the Revolution thanks to the camera remote. Push the center button, and a row of icons will appear on the video monitor. Select the “Exposure” Icon with the left and right arrow buttons, push the center button again, and following the instructions, set the camera to auto exposure mode (Sense Up) and give it that x32.  Using the remote was a joy. A whole lot better than trying to operate the camera with the wee buttons on its backside.

With the VX mount tracking and focus at least roughly dialed in, I was ready to begin. What was my first target? An astrophotographer friend of mine is wont to say, globular star clusters are God’s gift to imagers. She doesn’t just mean they are photogenic, but that their tiny stars are perfect for refining telescope focus. M15 was pretty much perfectly placed on this night, just beginning to descend into the west, so I typed M-0-1-5 into the NexStar HC and when the motors stopped their whining, had a look at the monitor.

Even in a short exposure, it was obvious we were on target. There was a suspiciously large "star" near the center of the screen. I upped exposure to 128x and refined focus. That was easy to do since I have a JMI motofocus on the C8. Which, like goto, is a huge help. Being able to sit at the monitor and focus with a remote control is just a boon, let me tell you.

M15 on a poor night...

After M15 was good and sharp, displaying a lovely halo of tiny little stars on the monitor (the screen grab here doesn’t do it justice), I began playing with the camera's settings—after running inside and pouring myself a glass of Merlot to keep me warm in the chilly 40s of the evening. I’ve often said learning to use an astronomical video camera is a lot like learning to play a musical instrument. You have to practice with it and try different things before you get good. While I’ve done a lot of astro-video, this camera was more or less new to me and I had a bit to learn—actually I still do—to get the best images out of it that it can produce.

Don’t despair if you are a newbie, though. Just using the recommended settings in the instructions, which give setups for general deep sky objects, lunar and planetary, and dim/large DSOs, will get you going. In general, it’s best to start out with the camera in automatic (Sense Up) mode before experimenting with manual (Lens/AGC) mode. Going manual is pretty much required if you want to capture the dim stuff, though.

What challenges did I face on this first extended run with the camera? It behaved itself very well, and once I’d reacquainted myself with the menus and settings it just got out of the way. The only problem I ran into was the brightness of the sky background. It took a while to figure out which exposures and other settings brought out objects best without washing out the background too much. That is always the way it is with video in the backyard, however.

What helped with sky brightness was screwing an Orion Imaging filter onto the camera nosepiece. This “mild” light pollution filter darkened the sky background appreciably without dimming star clusters and galaxies, which will be badly attenuated by stronger light pollution filters. A similar mild filter like a Lumicon Deep Sky or an Orion Skyglow will work just as well as a filter sold specifically for imaging.

Yes, I’ve got quite a few deep sky video hours under my belt, but I believe the Revolution will be easy enough to set up for anyone capable of following instructions. Mine was soon cranking out pleasing images and I was seeing a heck of a lot more than I’d have seen through the eyepiece of my 10-inch Dobsonian on this semi-punk evening. Like what?

The Deerlick...

M15:  Was very well resolved with tons of tiny stars shining steadily around its intense core. What was sorta amazing was that I had to be careful not to overexpose the core with this very sensitive little cam.

M27: was sinking, but that didn’t prevent the Rev from bringing out some nice reds and greens, the apple-core shape, and the central star.

NGC 7331:  Once I got the exposure just so, I began to see traces of the galaxy’s sweeping spiral arm, which is quite apparent in the live video. So are the little nearby NGC galaxies, the “deer” at the big Deerlick of NGC 7331,

NGC 6888: I wasn’t surprised to pick up the dim loop of the Crescent Nebula from a dark star party field, but it was quite a trip to watch it appear on my monitor in the backyard as the images stacked. Not just as a loop, but as a distinctly red loop.

M74:  While I thought it at least possible that I could have seen a trace of the Crescent visually with my OIII filtered 12.5-inch Dobsonian on a night like this in the backyard, I knew there was no way in hell I would have seen the dim arms of the Phantom Galaxy. The sky was now poor enough that I was not even sure I’d have seen the nucleus. Yet, there were the arms as the images stacked on the screen (I set stacking to 5 frames and left it there when I wasn’t focusing). Amazing.

And so it went till the clouds finally rolled in, preventing me from seeing what the Revolution would do on M42 (or the Horsehead). But that was OK. I’d seen a lot and been impressed. This is an inexpensive camera, but that is the beauty of the thing, since it is also a very capable camera. I’ve been doing video since 2003 and the antique Stellacam II days, but I was admittedly rather taken with this little thing (and plan to get it to the dark site soon). Two big thumbs up, y’all.

Nota Bene:  You can see more pictures of and by the Revolution on my Facebook page...