Video Astronomy - the adventure begins!
by, 06-16-2012 at 10:17 AM (777 Views)
Having read much about the benefits of integrating video cameras (Malincam et al) I decided to take the plunge. I want to do the Messier challenge(s) and it seemed a good way of being able to see/capture each object.
I've looked at many images snapped from such cameras and whilst clearly not as good as full-blown imaging with a CCD or DSLR, they are quick to obtain... and this is key for me as clear skies seem very hard to find at the moment.
However, a Mallincam is a serious financial investment. After some research it appears there are 3 "tiers" of such cameras:
Tier 1 - Mallincam, Stellacam etc
Tier 2 - Watec, Mintron etc
Tier 3 - Samsung etc
Thinking I would probably get a Tier 1 camera "one day", a Tier 3 camera seemed like a (relatively) inexpensive way to get a toe in the water...
More research revealed:
1) the best high sensitivity integrating Samsung available is the SCB-4000
2) this camera is available in both AC and DC (12v) formats
3) there is a very easy mod to remove the IR filter for astro work
4) This camera is available in "bare bones" format with no lens (good!)
5) It is readily available - mine should be delivered on Monday
In addition to the camera itself (I ordered the SCB-4000PH which is the AC version - I have AC power for all my astro gear as I am home based) there are various "accessories" required:
1) a C-mount to 1.25 nosepiece - I got one from FLO with a threaded lens cap for £15.
2) a proper "astro" 1.25" 5 IR filter that will screw into the nosepiece (I got the Baader UV/IR cut filter) I alos have a 1.25 moon/skyglow (Neodymium) that I use for planetary which I will try later.
3) a 10m composite video cable - a Belkin quality item was £6 from Amazon
4) a BNC-RCA adapter (95p from Amazon)
5) a USB frame grabber - I already had a Startech with composite and S-VHS inputs - the latter will be useful with Tier 1 cameras...I think these are around £30-£40
6) an RS485:RS-232 interface module - £18 from Amazon. This allows connection of the camera to my laptop via a USB:232 cable and gives remote control of the camera menus from the laptop in conjunction with some free software which I'll describe in a later blog entry.
Finally, more digging unearthed some capture software (free) that can stack 2 images from the Samsung in real time.
I know 2 images is hardly a stack, but it does reduce the SNR noticeably. The integration time of the Samsung in PAL mode is 10 seconds. This is tiny in comparison with the Mallincam xTreme for example, but it is still massive compared to our human eyes (roughly 1/20th of a second). So, this software can stack two 10-second images. I'll report back how well it works in practice later. It's a pity it can't also do a dark subtraction like PHD can... maybe there will be support for that one day.
So, I'm waiting for the postman to arrive with lots of small parcels.
Next time I'll report on the camera mod and setting everything up with the computer and all the wiring. Based on prior experience the worst mistake I can make is to attach the camera to the scope too early before everything is debugged.
I'll also have to decide how to attach the camera - I could go nosepiece straight into visual back...I'll try that first.