As hinted at in the "what are you thinking" thread, I'm currently considering advancing my CCD purchase a bit. As always, it's one justification leading to another... basically I still plan on going to a guided setup later in the year. That means I need a guide cam. But if I get the right guide cam, I can also use that for planetary/solar/lunar imaging too. And I could make use of that sooner rather than later.
So what's on my feature shopping list?
1: it has to be great as a guide cam. This is a must.
1a: to be the above, it will be a mono sensor.
2: it should be usable as a planetary imaging camera.
2a: capable of fast-ish frame rates. I don't know how fast is fast enough.
2b: pixel density should be on the higher end
2c: given the optics I have or will have, it would help to be a relatively big sensor. Note big in this sense will still be tiny in photographic terms.
2d: b+c implies a relatively high pixel count. Note high in this sense will still be tiny in photographic terms.
After a quick search, two models have caught my eye.
Starlight Xpress Superstar AutoguiderThe Imaging Source DMK 41AU02.ASBoth use a Sony ICX205AL CCD sensor and are priced similarly. It looks like the Superstar is a relatively new release so there isn't so much on it out there, whereas the DMK41 is a bit more established. While both share the same sensor, the Superstar lists a higher output resolution, so perhaps the DMK41 crops a bit? Maybe it's a video thing. The DMK41 specifies an 8-bit dynamic range which sounds limiting to me. The Superstar is a bit more vague saying it has 16 bit data output. Of course there's no guarantee those extra 8 bits provide any more meaningful data.
For comparison, the
Atik 314E also uses the same CCD but in a package designed for imaging. They have a 16 bit output but the framerate is incredibly low. Not important if the exposures are measured in minutes. Not so good if you want a lot of images fast. But this is a good example even if you have the same sensor, you can optimise the electronics around it for different conflicting needs.
Going back to the DMK41. At 1280x960 15fps and assumed 8 bit per pixel, that's just under 18MB/s uncompressed datarate. For comparison, USB2 has a maximum bandwidth of 60MB/s so we're comfortably under that. We can even afford to double that to 16 bits per pixel, assuming the USB protocol overhead doesn't eat into the maximum too much.
The Superstar's listed resolution is 1392x1040 and states 0.6s for a full resolution download over USB2. I think we can forget about framerates there.
So having gone through that, I guess the DMK41 is the choice if I want to attempt planetary imaging. Unless there's other models I've overlooked which might be even better.
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Then I scale back again to something attainable.