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Wide-field imaging rig from scratch


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I started with zero experience with a Canon 1000D that I immediately modded. Can't say I recommend that to anyone. I learned very little and the real learning - positive learning without frustration -

Widefield imaging rig - A term that in the context of this post I am finding a little ambiguous. Here's why, just from the CCD and scope point of view. I had a 460 chip and I use it with a Tak FSQ85 -

Thanks for your suggestions so far! red dwalf: I'll take another look at the WO GT81. Do you use it with a FF? pete_l: Yes, I originally looked at DSLR imaging but this approach doesn't appeal to me.

John,

The ccd choice isn't easy I'm afraid, but that's partly because there's some great kit out there.

I have an atik 460 and think it's excellent, (low noise and pretty sensitive) but wanted a bigger chip area when I got my FSQ85.  My STF8300M is also pretty good (if a bit noisier and less sensitive) but it does have almost twice the area.  However, the pixels are a bit bigger, so I find it less well matched to a reduced baby Q.  Both of these cameras are very capable performers, but the sensors are small when compared to an 11000 (which unfortunately has even bigger pixels).

Unfortunately, a 29050 camera (big area with small pixels) would blow your budget and they're slow to the market.

I would definitely sleep soundly buying a takahashi refractor, as expensive as they may appear.  Premium optics will always be so.  Today's mid range ccd will probably be a paperweight in ten years time.

FSQ85 or 106, can't go wrong with either of these.  85 is easier handling, shorter FL and just so so sweet. 106 has a bigger flat field.  (Most ED80's  are pretty amazing for the money too)

Atik 460/490 QSI 660/690 all excellent.

QSI 683 is probably the best implementation of the KAF8300 chip.  Atik 383 and SBIG STF8300 are both good too if cost is more of a factor.

See, not easy is it?

Guess this doesn't help much....

Jack

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Although the claim is often made that the FSQ85 will cover a full frame camera, it won't - if the full frame is a Kodak. These are larger than the official 'full frame' as defined by 35mm film and I know from experience that the Baby Q at native falls some way short of covering it.

Olly

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I would definitely sleep soundly buying a takahashi refractor, as expensive as they may appear.  Premium optics will always be so.  Today's mid range ccd will probably be a paperweight in ten years time.

Atik 460/490 QSI 660/690 all excellent.

QSI 683 is probably the best implementation of the KAF8300 chip.  Atik 383 and SBIG STF8300 are both good too if cost is more of a factor.

See, not easy is it?

Guess this doesn't help much....

Jack

Thanks, Jack! Regarding the CCD and paperweights. Yes, isn't bleeding edge technology wonderful. Been there, done that (digital cameras, routers, TVs, laptops, smartphones, the list goes on)  :smiley:

I guess Moore's Law applies to CCDs as much as it does to computing hardware. Hopefully the Avalon mount and Tak will outlast the CCD!

John

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Although the claim is often made that the FSQ85 will cover a full frame camera, it won't - if the full frame is a Kodak. These are larger than the official 'full frame' as defined by 35mm film and I know from experience that the Baby Q at native falls some way short of covering it.

Olly

So given that I'm leaning towards a QSI all-in-one solution (CCD/FW/OAG) what's your view - QSI-683 WSG-8, QSI-660 WSG-8 or QSI-690 WSG-8? Again, just to be clear, I'm trying to match the CCD to a Baby Q (native) and EdgeHD 9.25".

John

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 I'm trying to match the CCD to a Baby Q (native) and EdgeHD 9.25".

The Tak has a focal length of 450mm. The Celestron has a focal length more than 5 times that.

If you want to use one single camera at both those focal lengths you will need to compromise somewhere. Either the Tak will be sampling at 2 arcsec/px (not too bad) and the Celestron at 0.4 (very over-sampled: excess noise, unless you  "bin" and put up with the lower image size) or the Celestron will have a camera with pixel sizes that match its focal length and the Tak will be giving you square stars.

Take the focal length in millimetres. Divide that by 200 and the result will be the pixel size in microns for about a 1 arcsec/pixel resolution.

Find the range of resolutions you will be happy with, run the numbers and look for a camera with that sized pixels. However, bear in mind that these days pretty much all cameras have a pixel size in the 3.5 - 6 micron range.

Edited by pete_l
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Wish I had a spare 8K to spend on astro gear :D  Mind you, I may well have spent that in the past - sometime I'll do a stock take :D

Widefiled to me means a lot wider FOV than the OP suggested.  I have used Asahi SMC Takumar prime lenses with my Atik 460EX with success but I'm working towards a wider FOV by trying to convert a DSLR to mono.  I appreciate that this comes nowhere near anything like the Atik 11000 CCD but I have far more patience than funds and now it would seem that funds may be even more limited in the future :(  Also I love a challenge and that is a BIG one :D

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