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On-Axis Guider or Self-Guided Camera?

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#1 Steve Drapak

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Posted 15 January 2013 - 10:56 PM

I'm planning on replacing my QHY8, not sure whether to get a self-guiding camera (SBIG or QSI) or to get a less expensive camera and use the new on-axis guider (Innovations Foresight).

Using off-axis is pretty tough where I am, lots of light pollution makes it hard to find a guide star (and just generally frustrating in any case), and really the only complaint I have with the QHY8 is that it's a pain to keep it dry and frost-free on the CCD, so my personal lean is towards getting a sealed QHY8L instead and the on-axis guider. Wouldn't add a lot of cost.

A self-guiding camera would have less optical surfaces than a setup with a cold mirror, which might give a little more efficiency. I really can't say I know a lot about the self-guiding cameras yet.

One extra potential option would be adding an AO unit in the future. It might be cheaper to add an SBIG one than one that works with other systems like the Starlight Express unit, though I think the overall cost is still more with SBIG.

Opinions?

#2 D_talley

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Posted 16 January 2013 - 08:20 AM

I understand your pain with the QHY8 and frost. I have yet to make an image with mine because I am working on ways to fix the frost issue.

I use the On Axis guider from Innovations Foresight. It gives me a lot more guide stars to work with. I live in the light polluted city. I use it with my Meade 12 inch SCT. I use a DSLR to image with and hope to try out the QHY8 with it the next clear night. I did use a SBIG ST2000 camera but sold it since it took 4 times as long to image since it was mono.

#3 orlyandico

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Posted 16 January 2013 - 10:28 AM

I've been using a QHY8 here in Singapore for some years. It's very humid here and frost has also been a concern.

What I do is make sure the air inside the camera is really dry. I leave the camera with sensor open to the air inside a sealed plastic bag (one of those vacuum laundry bags) with a jar of silica gel inside.

After a day inside the bag, I close up the camera without opening the bag. Seems to be working so far...

#4 Steve Drapak

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Posted 16 January 2013 - 10:30 PM

I had a previous QHY8 that putting in a bag with the silica worked, but long story short it had a problem, sent it to QHY over a year ago and not a peep, so KW Telescope was nice enough to lend me one in the meantime. May not ever see the old one again, and this lent one resists every effort to seal and dry. I finally resorted to buying a CO2 dust blower to remove all of the air out of the camera - though haven't had a clear night in the last couple of months to try it yet :p If that doesn't work I'll have to chuck it. Not sure I can sell it since it's technically not mine :)

#5 Steve Drapak

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Posted 16 January 2013 - 10:34 PM

Should mention, one of the reasons to go with the on-axis guider or a built in one is that I can't get my telecompressor close enough to the camera to avoid viginetting. It's housed in the moonlite focuser, and with an off-axis guider in between it and the camera, it's way too long a distance. Could put the telecompressor after the off-axis guider, but had trouble finding a connector with the right threads and I'd rather go with a nice shiney new solution anyway :)

#6 MHamburg

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Posted 17 January 2013 - 08:22 AM

If you wanted to connect the telecompressor after the the oag, you can get a beautifully made adapter from www.preciseparts.com.
Michael






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