QHY9, some questions.......

[Bassnut (Fred)]

Ive had a close look at this cam on the net, see some users here, and read up on posts on it. The QHY spec seems seems pretty good for the price, much less than FLI/SBIG equivalents. The images ive seen also look good.

As already discussed, the 25K well depth isnt flash (problably translates to 14bit in reality), but everything else looks good, the cooling on the QHY9 looks good and regulated (which I assume means you can set it), and the QE isnt bad. (BTW, is the temp inserted into the FITs header for auto darks selection/scaling in DL/CCD stack?).

Specifically, I have invested a lot of $ in 1.25" format filters/focuser etc, and am thinking of an AO8 for my ST10.

My question is would a 1.25" filterwheel/AO8 show that much vignetting?. Im thinking of useing the AO8 on the QHY9, with the ST10 mounted off the imaging train, but its external cam providing AO guiding via a MOAG. This provides AO guiding without investing in another big-chip SBIG. Im also hoping my TCF-S focuser will do, its 2".

Theo has already told me vignetting will occur with 1.25" filters, but I wonder how much, a little cropping would be acceptable without getting silly and wasting all those extra MPs . Eventually, a 2" filterwheel would be the go, but Im hoping to get by for a while without that).

Anyone got pics with 1.25" filters?.

Are the QHY9 users here happy?, the eary versions had some bugs that seem to have been addressed.

[Gama]

The QHY-9 has the Kodak 8300, as does many other cameras.
Images will be the same on all new cameras having this CCD as long as temperature is low, and the guy who processes them knows how to.

The well depth of the Kodak KAF-8300 is low and the QE not too bad, but suprisingly it still produces decent images.
It has lower noise than its older sisters, so again this is a plus.
Any camera with this sensor if found cheap, should be snapped up. Regardless of brand, and as long as it has good cooling, your on a winner.

The QHY-9 does have regulated cooling, just set and forget. It is capable of -50 deg C delta max, so it does its job here well.
Its light, only 500 grams, and small, about 110mm diameter and about 70mm long, so pretty small.
The issues with light leaking in during daytime darks was fixed, although not many camera are totally light sealed for absolute darkness for daylight darks either.
The main issue was with the users applying a DC overvoltage to the input of the camera, normally due to wrong power supply used. Again this was addressed and subsequently, a new board was designed to withstand most user errors.
A note to this, is that all cameras sold previously have had the old board replaced free, so you wont be stuck with a "early" model. They will all be the same.

As for Images, they are out there, just need to sort out where and who took them..
Remember the cameras only been around 3 months now.

The info of the camera, exposure, temp set and temp during exposure etc are all on the FIT information window.

Vigneting, as i mentioned to you..
I use my QHY-9 without filters, reminds me when i first bought the SXV-H9 when it was first released many years ago. Never had filters back then either..

Theo

[CometGuy]

Fred,

I've only had mine for a week, but very pleased so far. I'm using mine for sky survey work to replace my Canon 350D and the improvement in sensitivity is huge.

Unlike the earlier days software support is now excellent (as is the qhyccd forum for general user support).

Terry

[Hagar (Doug)]

Hi Fred, I have had my QHY9 for a while now. I think mine was one of the first shipment to Australia and I am very happy with the overall performance of the camera. The 8300 CCD does exhibit a lot of hot pixels but these are easily removed. As for sensitivity it is great. I am pushing it quite hard running at 0.65 pix/ arc sec with my VC200L and the results are quite pleasing.
The backup and after sales service from both QHY and Theo are great. The smallest glitches are investigated and usually corrected the same day. Most of the early teething problems and software compatability issues have been addressed so the camera will now work with most major capture programs.
1.25" filters, I don't know as I have only used 2" filters and have only had them a short while. The Filter wheel is great and is fully integrated with the camera control.
Examples of my results with this camera can be seen here.
http://www.darkskyau.com/cm/thumbnails.php?album=27

[Bassnut (Fred)]

Theo, yes ive read the recent fixes and the support looks very good. Thanks for the info.

Terry. The forum was informative, a lot of feedback there, good luck with yours, look forward to 1st light.

Doug. Ive seen your images as you posted them, and am impressed, they have perked my interest in the cam more and more.

The closest competition I can find (also a KAF8300) is the QSI583wsg for OZ$6k odd with a built in filterwheel and OAG, (which is cool, since Im after an OAG) but with shipping and GST a bit more expensive even with the extras, and I dont know what the support is like.

[rally]

Originally Posted by Gama

T
Any camera with this sensor if found cheap, should be snapped up. Regardless of brand, and as long as it has good cooling, your on a winner.

Theo

Theo,

The Olympus E300 DSLR has the KAF8300 colour chip.

I am aware that people have modded them - (IR and anti-aliasing filter removal), but not sure if they can be cooled as easily.

The advantage is they are almost always available for well under $300US
I have seen them with two lenses for around $225 !!

They actually have a die cast metal body which means that it could be possible to attach a peltier to the body and cool it externally ?!

If its anything like the Olympus E1, the CCD can be cooled by attaching a peltier cooled adapter to the Camera's lens bayonet flange as there is a thermal conduit straight to the CCD.
But that is purely hopeful speculation for the E300 without dismantling one to verify it.

Obviously this is no good if you want to RGB image (without replacing the CCD to a mono version)
Hmmm - I wonder how much a mono KAF8300 chip costs !

Cheers

Rally

[Bassnut (Fred)]

Rally

Ive often wondered about fitting a mono sensor in a DSLR, I suspect replacing a large mutipin pin surface mount sensor chip wouldnt be easy, and the firmwear would be all wrong for it. It maybe possible to scrap the bayer data in the RAW file output leaving just the full res mono image, or just convert to mono. Would be interesting to see if that would work.

[rally]

Fred,

I looked into this in some detail once before - exactly the same thought !

There is no electrical difference between the mono and colour chips as far as I can see from the Kodak specification PDFs.

And there is No need for a firmware modification (impossible) all you do is download the RAW file and decode it as a B&W image (without bayer) using the DCraw utility as a mono - its what is used by many of the commercial software developers.
It can be batch driven, command line or with gui - so that is easy.

You just need the right gear to desolder the CCD - it will literally just fall off - that is not so hard - providing you can get someone else to do it with the right gear for you.
You couldn't even think about it using a conventional soldering iron or trying it yourself !!

The hard part is actually trying to buy one KAF8300 mono chip - I couldn't find one available anywhere, but then I didnt actually start making phone enquiries either.

Maybe someone out there can tell us ?
If so I would get one providing they are not ridiculously expensive.
I think I have 2 or 3 E300's lying around that could be modified.
They are a very rugged, bullet proof DSLR

Cheers

[Bassnut (Fred)]

Rally

Been thinking about this. Im not sure decoding a RAW image to mono is quite the same as just not decoding at all and treating each sensor pixel data as mono which would increase res by 4. I suspect the standard mono decode would calculate "mono" from the colour bayer data, ie convert 4 RGB pixels to B/W based on the RGB wheighting of each colour sensor pixel. Thats why I thought just junking the bayer data would be best. What do you think?

[Ken]

Hi Fred Have just seen this post, I did test images on Eta Carina a while Back using 1.25 colour filters because I had no 2". The filter wheel was not used just used a adapter to screw each filter into the camera nose piece. I saw no vignetting when the images were stretched. Sorry the images went into the recycle bin. The slim filter wheel positions the filter very close to the ccd chip.
Clear skies Ken

[Bassnut (Fred)]

OK, thanks for that Ken, DSLR clip in filters are also very small, which made me wonder if a thin, close 1.25" wheel would do the trick, nice feedback.

[srchadwi (Steve)]

Hi Fred

I'm having the same thoughts regarding the QHY9. I'm very interested in getting one but not too keen on shelling out loads on 2 inch filters when I already have plenty of 1.25".

I could get my ATIK filter wheel very close to the camera. I realise that vignetting is going to happen at fast focal ratios but has anyone got any idea how fast it is likely to be before it becomes a real problem? I tend to image between f6 and f11. I don't mind shaving some off but obviously I wouldn't want to loose to much field of view.

Thanks

Steve

[Gama]

Steve, why not get a pencil, and draw your focal length on a long long piece of paper and trace out the ray path and then use the measurements of the backfocus and filter placemnt in front of the camera to see exactly how much vignetting/cuttoff your going to create.
This is a true life measurment, and will give you not only a visual representation of the result, but also answer your questions on any other f ratio.

Theo