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Old 09-10-2012, 08:39 PM
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Camera Recommendation?

I think I am reaching the end of the road with my current imaging camera, a Moravian G2-8300. I cannot fault the camera, but it is a poor match for my PMX; after a year of frustration with drivers it may just be time to say enough is enough. The PMX is so heavily reliant on TheSkyX that it is imperative to have a camera that functions well in all aspects with this software. The camera will run with ASCOM but there are still a few irritating bugs in TSX and CCDSoft with no resolution in sight, and running through MaxIm to TSX doesn't solve those issues, unfortunately. I am quite sure that in any setting outside of the Software Bisque world the camera is fine. It wasn't a well researched choice (in terms of software) on my part when I ordered it (I was overly focused on hardware), but even in retrospect, it would have been hard to pick some of the issues that have emerged over the past year (many of which have been solved).

My scope is a TEC140....900 mm fl/f7. The KAF8300 gives me 1.14 arcsec/pixel which is probably more resolution at 1x1 than I can effectively use given light pollution and not great seeing where I observe.

So, I wonder if going with another KAF8300 camera is the right move? I'm just getting started in this hobby/obsession so perhaps a camera more in the 2.5-3.5 arcsec range might be a better match....but, I'm not sure. If I do stay with the KAF8300 CCD I've read very good comments about the FLI Microline, and the SBIG solution. The QSI also has been suggested and to me seems to have the advantage of an inbuilt filter wheel and a guider option (and I could retain my existing 31mm filters). Saving weight and simplified mounting is appealing (and pretty much are the reasons I went with the Moravian camera in the first place).

If asked, what do I want to image, I have to say a bit of everything that is possible! In other words I have no desire just to image nebula, or galaxies, or globular clusters; I want to try a lot of different things to find out if I might develop a particular passion.

I can't exactly say cost isn't a factor...it is, but I don't want good suggestions to be limited, or not suggested, because of cost. I'm willing to pay for quality. After so much angst I just want a good reliable and working solution!

Suggestions much appreciated!

Peter

Thanks for your thoughts!
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Old 10-10-2012, 12:09 PM
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KAF8300 is a good chip but rather small and small well capacity which sometimes is a factor in bright stars on fast systems looking bloated.

KAF16803 is currently the king of chips and will bring out the best in your TEC140. See Marco's images to see what it will look like.

FLI Proline 16803 is a great camera, but if weight on focuser is an issue (it isn't on TEC140 but is on some scopes like FSQ and many others) then get the Microline 16803 which is currently the only lightweight 16803 camera out there.

QSI have many happy customers and the 6 series brought it up close to the FLI. But they max out at KAF8300 which is limiting. Apogee also do 16803 and so do SBIG and Starlight Express. SBIG has the best range of
autoguiding solutions but STX is very heavy and requires the even more expensive 65mm filters.

So currently FLI Microline 16803 is possibly the best allrounder, couple it with a MMOAG and an SBIG STi guider and you are all set for several years. Apogee U16M is also a popular camera although it has quirky slow cooling that takes a long time and resists control by the user.

It seems the pace of new chips has slowed due to Kodak selling its sensor business. Also astro market is tiny so chip development is more for X ray, scientific instruments and perhaps machine vision than astro. Also high end medium format cameras.

Greg.
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Old 10-10-2012, 12:28 PM
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Hi Peter,

I went with a KAF8300 chip; specifically the STT-8300M, though I am still awaiting its arrival so I can't really comment to its performance just yet.

For me, I'll be imaging numerous targets at f/3.6, f/5, and f/8 with an FSQ106 refractor. My major concern with the chip while deciding are a few issues with binning, but this doesn't seem to be a major issue and you just need to be aware of the limitations and account for them.

I've seen some good results with a KAF8300 and the TEC140. There should be a few people on here who would have experience using these chips, a fair few people post images on here captured with either the QSI or SBIG variants - even in light poluted locations. Have you looked into narrowband?
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Old 11-10-2012, 02:36 PM
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Hi Greg and Chris,

Many thanks for your suggestions!

Greg the FLI FL16803 certainly looks to be a gem of a camera, but is probably more than I can afford in good conscience at the moment. Off line I had a suggestion to consider the STL11000M which I believe has 9 um pixels. I see SBIG doesn't make the camera any longer, but I suppose they would still repair if necessary (?). Greg, I'm curious how you mount your cameras to the TEC? Do you use the helical clamp on the FeatherTouch, or do you remove the clam and have everything screwed together. Also wondering if my focuser will allow me to get full illumination of these larger chips?

Chris, I'll be interested to see how you go with the new SBIG camera. It certainly offers some interesting features, that's for sure!

Pete

Last edited by PRejto; 11-10-2012 at 03:15 PM.
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Old 11-10-2012, 03:42 PM
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Greg the FLI FL16803 certainly looks to be a gem of a camera, but is probably more than I can afford in good conscience at the moment. Off line I had a suggestion to consider the STL11000M which I believe has 9 um pixels. I see SBIG doesn't make the camera any longer, but I suppose they would still repair if necessary (?). Greg, I'm curious how you mount your cameras to the TEC? Do you use the helical clamp on the FeatherTouch, or do you remove the clam and have everything screwed together. Also wondering if my focuser will allow me to get full illumination of these larger chips?



Yes 16803 isn't a cheap option but they do come up every now and then on astromart. In fact wasn't there one for sale in Melbourne recently - the Apogee U16M with the high cooling body and filter wheel and filters. Julian.

Anyway, STL11000M is another classic camera and I agree 9nm pixels seem to be the sweet spot with Kodak technology and local seeing for most focal lengths.

I attach to my TEC flattener with a custom adapter from Precise Parts.
I would not use eyepiece holders for cameras as that is asking for flex or worse the camera slipping out when it gets cold (that TEC clamp loses grip if temp drops too much).

STL11's often come up on Astromart. Filter wheel and guiding for LRGB in one package. Remote guide head for a guidescope for narrowband or use STi guider with the lens guide package. Or simply add a MMOAG and guide through that with an STi. You can also get an 8 filter filter wheel for the camera.

FT 3.5 inch focuser does not inhibit 16803 chip at all and is a nice piece of TEC scopes. TEC make their own focusers now.

I've had 2 STL11's. The colour version and the mono. Great cameras, loved em. Very convenient and a lot less fiddling with cables, transformers etc.

Greg.
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Old 12-10-2012, 03:18 PM
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Greg, Many thanks for the additional information!

This discussion is reminding me just why I decided initially on the KAF8300 CCD.....it's just about the correct size that I can get away without a flattener on my TEC140 for one thing, and it seems to offer performance for a reasonable cost. I know the pixel size is not optimal and the well depth is shallow, however. Is it a mistake to think that any of these shortcomings can be addressed by binning 2x2 with the KAF8300? I don't think well depth is changed by binning, but at 2x2 I'd be at 2.24 arcsec/pixel.

Peter
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Old 12-10-2012, 06:23 PM
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What bothers me about the 8300 is that they didn't make the output register large enough to avoid overflow when binned. That hasn't stopped me from owning one though.
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Old 12-10-2012, 06:39 PM
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I still think the QSI-683wsg is a good camera, but I gather I'm a statistical outlier.
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Old 12-10-2012, 09:47 PM
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Originally Posted by PRejto View Post
Greg, Many thanks for the additional information!

This discussion is reminding me just why I decided initially on the KAF8300 CCD.....it's just about the correct size that I can get away without a flattener on my TEC140 for one thing, and it seems to offer performance for a reasonable cost. I know the pixel size is not optimal and the well depth is shallow, however. Is it a mistake to think that any of these shortcomings can be addressed by binning 2x2 with the KAF8300? I don't think well depth is changed by binning, but at 2x2 I'd be at 2.24 arcsec/pixel.

Peter
Actually Peter, the 8300 is close to ideal of 1arc/pixel on a TEC140. 8300 isn't ideal at 2 or 3 metres though as it gets too affected by the seeing and 9 microns performs noticeably better. I use both and I stopped using the 8300 on my CDK 17 for this reason. If you had superb seeing or were using an AOL it may be ok.

TEC140 though it should be perfect. Its just not a very wide field of view and TEC140 is capable of wondrous widefields.

You can bin but you would only need to do that if seeing was terrible or you wanted to get Ha fast etc. Otherwise no need to bin it.

To me larger chips are always better than smaller chips as FOV is everything.

Greg.
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Old 14-10-2012, 03:35 PM
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Ernie and Greg, Thank you both for your replies.

Ernie, I certainly am paying attention to your QSI recommendation! If you had to pick between the QSI and the new SBIG which way would you go? Would you expand on your comment about the binning problem? What is "overflow" and what is the result?

Greg, I have to say that at the moment I'm not too keen on spending more money for a TEC flattener and a new camera, and a new mounting system. I still have so much to learn. It does seem I could keep things a lot more basic by staying with the KAF8300 for now. I guess I'm confused about the point re resolution. I've been reading Ron Wodowski's book which seems to say that 2-3 arcsec/pixel is ideal if seeing won't support greater resolution. So, I guess my question is if I'm using full resolution with a KAF8300 (1.14arcsec) and seeing is marginal am I actually worse off than using a camera with larger pixels, or just not getting the resolution I could if seeing were ideal?

Someday, for sure, I will get the flattener and a better camera and hopefully will enjoy the wondrous wide field views!

Thanks!

Peter
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Old 15-10-2012, 07:35 PM
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Greg, I have to say that at the moment I'm not too keen on spending more money for a TEC flattener and a new camera, and a new mounting system. I still have so much to learn. It does seem I could keep things a lot more basic by staying with the KAF8300 for now. I guess I'm confused about the point re resolution. I've been reading Ron Wodowski's book which seems to say that 2-3 arcsec/pixel is ideal if seeing won't support greater resolution. So, I guess my question is if I'm using full resolution with a KAF8300 (1.14arcsec) and seeing is marginal am I actually worse off than using a camera with larger pixels, or just not getting the resolution I could if seeing were ideal?


It comes down to sampling theory which states you need at least 2X to get a decent sample. In practice that goes to 3. So if you get 3 arc second seeing which is common then around 1 arc/second per pixel then is ideal.

Ron has a calculator that works out the various camera/scope combos and calculates the arcsec/pixel.

But around .66 to 1 is good based on the above. The longer the focal length then will mean your 5.4micron KAF8300 pixels are oversampling too much and unless you get excellent seeing where it brings you back closer to those numbers you will find fuzzier images than a 9 micron camera. I have seen this in action with my CDK17 where my FLI ML8300 gave quite poor images of M83 whereas same scope, my Proline 16803 gave quite noticeable superior details and sharpness. I did this several times so it was not just seeing conditions on the night.

I think you will find examining posted KAF8300 images that the ones that seem the best or seem to have a sparkle are taken with scopes under 1500mm focal length and the shorter the better.

Look at Martin Pughs recent image with a lens and 8300 - it was very vibrant - more so than if he had've used a 9 micron camera.

On the other hand look at long focal length 8300 images. Unless they were taken in Namibia or somewhere with great seeing they seem "stretched" like expecting too much from it.

Greg.
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Old 15-10-2012, 07:49 PM
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Originally Posted by PRejto View Post
Would you expand on your comment about the binning problem? What is "overflow" and what is the result?
When binning, the sensor has to add the contents of multiple pixels together and the KAF8300 does this via a horizontal shift register that isn't big enough to hold the maximum possible number of electrons. The result is horizontal blooming as demonstrated here:
http://www.pbase.com/wjshaheen/horiz...he_kaf8300_ccd

Some cameras reduce this effect by turning the gain down when binning. I believe the QSI cameras can do this. It's not a perfect solution but I presume it controls the blooming.

Cheers,
Rick.
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Old 16-10-2012, 11:54 AM
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Ernie and Rick, Many thanks for calling my attention to this binning issue. It is something I never would have suspected on my own; I'm not sure if I've seen this effect at 2x2, but I have seen distorted stars. Might be mistracking or maybe something to do with binning distortion. I had hoped to use 2x2 for quicker RGB captures and reserve 1x1 for lum. Not sure that is such a swift idea anymore!

Greg, thanks for your explanation about seeing vs pixel size. I learn a lot here!
Peter

PS Moravian has come to the party with another revision of the ASCOM driver that seems to finally address all my remaining concerns. So, for the first tme in more than a year I have a fully functioning camera running CCDSoft and TSX. WooHoo.....no new camera for the time being, anyway!

Last edited by PRejto; 17-10-2012 at 07:41 AM.
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