Getting started in video astronomy - my experience so far

[cathalferris]

Over the past few years, I had seen many posts on various forums about the use of sensitive security cameras for astronomy, and my interest was piqued. A few months ago, I saw a Samsung SBC4000 (one of the 1/2" chip sized cameras) for sale for a good price.

It arrived, I picked up a few C-mount lenses, a 1.25" to C and an EOS-to-C adapter cheap from the Bay and I had some fun modifying the camera and removing the IR filter. To use it I had to run leads from my TV indoors through the kitchen to the back yard, as I didn't have a portable monitor to hand to show the output.

My indoor testing showed just how sensitive this camera was to IR, as I was watching my remote controls flash as I used them. Also the fire was casting shadows the wall that I could not see by eye. I also used this camera to finally verify that my green laser pointer did in fact leak a large amount of unfocused IR - tested using a CD as a diffraction grating.

My early outdoor testing showed that with a 4-8mm f1.6 lens, I was able to reach below naked eye visibility. I had not had any opportunity to attach to any of my scopes, as my cables wouldn't run that far!

Finally got around to getting a little LCD monitor, after being very surprised with the lower costs of the screens aimed at the automotive sector. Only €20 got me a 3.7" 640x480 screen, powered by 12v and using a composite input, delivered to the door.

So, on the night of the 23rd, it was clear for the first time in a while, and I was finally able to put all the components together. I put the 6" on its mount on a mat on the lawn, polar aligned, and then stuck the video camera in and focused on Rigel. Then on to M42 and I was very very surprised to see that much colour and detail..

(tbc)

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[Rick_G]

There's somethng really cool about looking at the night sky with a high sensitivity video camera. About 6 years ago, I purchased a Stellacam III. It's a monochrome camera but will allow the stacking of multiple frames in the camera. I used it with my Meade 10" LX-200 classic with a F3.3 focal reducer. I could get down to magnitude 13 ... maybe a little more. October a year ago, I got images of Comet Ison with it. The images are a bit grainy but you're looking at stuff in real time ... and seeing a lot dimmer then looking through the eyepiece. If the comet had become active, I would have seen it right then and there. I have also observed very dim and tiny objects moving through the field of view when observing M27 with the camera ... probably a satellite but it gives you a styrange feeling.

Rick Goodman

Mechanicsburg, PA.

[cathalferris]

I think that I have definitely been missing out by not getting involved earlier in video astronomy.

Last night was nice and clear and cold and fairly dark as well, so I set up the LXD75 for a final shakedown before I deliver it and the 6" OTA to its new home. I set up up during my food break at work, so that things would be nice and temperature stable as I finished work for the night at about 1am. The polar align was showing as <5 from the pole and the 2-star align brought both stars dead centre in the eyepiece FOV.

Camera settings: My site is dark enough that the "fix-256" with AGC at very-high, DNR of high is about right, and I can go to fix-512 and AGC of high for some things. My screen is a tiny 3" diagonal LCD that is a featherweight and I can use the slightly low viewing angle on it to get contrast changes on the fly when something is on screen.

With a 50mm f1.8 Canon camera lens and unmotorised just sitting on a tripod, I'm reaching about mag 10 or 11. This may allow the video camera to be used as a super-finder, and gives me thoughts for my future observatory.

I first had the 80mm refractor on the mount, and I was doing a quick whistlestop tour of the bright and shiny things, M51 showed clear spiral structure, M42 was just amazing with full colour and I finally got to see Hubble's Variable Nebula. No sign of nebulosity in the Cone nebula, but I was seeing hints of the Running Man. M1 showed tendrils and looked pretty much like older photos.

After a bit, I swapped the 6" Newt in instead of the 80mm refractor, to see what the difference in aperture and focal ratio (f5 instead of f6.2) would be. M42 wasn't a whole lot different, Still no Horsehead visible, Rosette nebula started to be visible, then I figured I'd go galaxy hunting now that Ursa Major and Coma Berencies were clearing the surrounding houses. M51 was very pretty, could follow the spiral arm across the companion. M97 was unsurprisingly owl-like . I opened up the skysafari app on the phone and started picking galaxies at random from the screen. The Whale, the Cocoon, the Silver Needle - all evocative names and all looking very obvious on-screen. NGC4565 was stunning, easily seeing the full extent of the galaxy and tracing the dark lane across most of its length. M53 was pretty, M3 was more so. M64 was sporting its usual black eye, M63, M94, all seen and looked at. M81/82 would almost fit on screen together, with great detail seen in M82.

The combination of 6" scope and the SBC4000 at 512 integrations was reaching deeper than mag.15 for stars, I was seeing dimmer stars on screen than were in the SkySafari Pro catalog. I have noticed that with the AGC set to high and the noise reduction set to high as well, it often takes 10-15 'cycles' of integrations before the image is stable, and it's well worth waiting for that .

I had the 12" dob set up beside the 6", and I was fond of comparing the views between the two. There was more to be seen with the 80mm scope and video camera than I could generally see with the 12". I know I didn't have full dark adaptation etc, but the comparison was very interesting.

It's nearly a pity that I've agreed to sell the 6" and LXD75 mount. However, I'll get myself a half-decent EQ platform for the 12" Dob, and with a 0.5x reducer on that scope with this camera could make for some very very interesting live images. Hopefully I'll be able to get an iOptron Cube mount for the two little refractors I have and that will give me a grab'n'go video astronomy setup that I can transport and set up quickly.