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Old 21-02-2014, 04:59 PM
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lazjen (Chris)
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CCD Camera for my system

I'd like to move to a CCD camera setup for my system (see sig for details), so I've been trying to work out what would be ideal. The problem is, I'm not quite sure what questions I should be asking and answering, so I've been dithering for a while.

What do I need to consider for doing this? About the only thing I know is that I want to go mono CCD + filters. I also want a system that I can cool well, since the summer nights around here can be quite warm.

If it means anything, with my current setup, the Canon 6D is full frame, so I've got the components in place to handle that size (approx 50mm+). I'm not sure how much I would "lose" if I went back to the smaller (1.25"?) system.

Btw, I'm aware that "cost" will be one question I need to answer, but I'd like to know what I'm giving up if I need to reduce cost to a lesser option.

So, any pointers appreciated, thanks.
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Old 21-02-2014, 06:38 PM
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What sort of targets are you interested in, Chris?

At that focal length and with the sort of seeing we get in SE Qld you won't want a sensor with small pixels, although binning is an option if you get a sensor that does it well.

Are you using a full frame sensor already on the GSO RC10 without a flattener or reducer? Last time I tried that on my RC10 the corners looked pretty awful!

Cheers,
Rick.
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Old 21-02-2014, 06:56 PM
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I generally have been doing deep space objects. Besides doing images, I'd like to explore other areas - like perhaps SN hunting.

I definitely have a FF. It's a TS 2.5" FF. I also have a 0.67 FR as well, but I don't use it as often as it very slightly vignettes the system with the 6D.
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Old 21-02-2014, 08:11 PM
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Doh! Dunno how I missed the flattener in your sig.

The ICX-694 sensor is pretty popular around these parts. It has low read noise and good QE but only small pixels and it's not a big chip. On your scope it would give you an image scale of 0.46 arcsec/pixel. That's probably way too small. Binned x2 it would be 0.92 arcsec/pixel which would work well. Overall FOV is small at 17.1x21.4 arc min. Good for galaxies but small for a lot of other DSOs.

I wouldn't bother with the KAF-8300. Image scale is not a lot different to the ICX-694 but it doesn't handle binning as well. It's a little bigger overall but also has higher read noise and dark current.

For a bigger FOV you'd need one of the big boys: a KAI-11000 or a KAF-16803. These both have 9 micron pixels giving an image scale of 0.93 arcsec/pixel which works well. FOV would be 41.3x61.9 arc min for the KAI-11000 and 63.3x63.3 arc min for the KAF-16803. These would give you a nice FOV but will be spendy and you'll need a hefty focuser.

Hopefully that gave you something to think about. I think the big decision is how big a FOV you want and whether you can afford it.

There are some new large sensors about but I'm not au fait with the specs. They won't be significantly cheaper if you want a big chip...

Cheers,
Rick.
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Old 21-02-2014, 08:52 PM
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lazjen (Chris)
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Thanks for the reply. You didn't miss the FF & FR, because I just added them when I realised they were missing.

So what I need to aim for is around 1 arcsec/pixel.

I'll look closer at the options. I may just have to save up for a lot longer to get the bigger options. I wonder if the moonlite focuser will be adequate with those?
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Old 21-02-2014, 09:02 PM
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There's no point in having an image scale that's smaller than around 1/3 of your seeing. You won't get any better resolution and you'll need more imaging time to get the same SNR. For long focal length I'm running at 0.67 arcsec/pixel and I don't often get seeing that justifies it.

The cameras vary quite a lot in weight but generally a camera with a bigger sensor will be heavier, especially if it has heavy duty cooling. Have a look at some camera specs and see how they compare with the capacity of the focuser. My Apogee U16M and filter wheel is 5 or 6 Kg
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Old 21-02-2014, 10:38 PM
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*sigh* 8lbs lift capacity on my moonlite focuser. About 3.6kg unless I upgrade that as well.

I jumped to sbig's page and found the STXL 11002 - 2kg. Haven't found what the filter wheel is, so it could be tight (and I noticed the AO-X as well...). Mind you I haven't quite worked out what body part I can sell and do without to afford it yet... :p

Given the price range involved here, I think I better save to a heavier duty focuser as well.
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