QSI 6120 vs 690

[Horwig]

I'm sure my numbers will come up in the lotto, so how better to spend the dosh, head says 690, heart is urging 6120, but anybody actually using a 6120 yet, and what results have you had?

Huw

[Physopto]

Hi Huw,

 What are you going to use it with? I have a 132mm W.O. scope and both 583 and 683 QSI cameras. I did not go for the 690 as a) the sensor is about half the size. It means the image would be reduced in breadth of sky imaged. The effect would have been like a 170mm scope, approx. and the 6120 has good Q.E. on paper and less noise but I wanted the same area covered as with my other CCD, any less and I would have had to buy a different scope. Another added expense!

Regards,

Derek

[Horwig]

Thanks Derek, I'm hankering after a small pixel camera to match a Pentax 300mm ED lens. The 6120 will give me 2.13" per pixel, but the 690 has a slightly longer diagonal, and squarer sensor, and a fraction higher SNR, but which one wins, no idea.

Huw

[Physopto]

Thanks Derek, I'm hankering after a small pixel camera to match a Pentax 300mm ED lens. The 6120 will give me 2.13" per pixel, but the 690 has a slightly longer diagonal, and squarer sensor, and a fraction higher SNR, but which one wins, no idea.

Huw

Hi Huw,

 Looks like you are well on your way to sorting it out. I can't recommend the QSI CCDs high enough. I have had the 583 for about 4 years. Great camera. The 683 is better but only on download times. It also has the 8 position filter wheel. It would have cost a ridiculous amount to upgrade the 583 from 5  to 8 position. So to cut a long story short bought the 683 with 8 position wheel as well. I recommend getting the 8 position, then at least you cover most eventualities. As soon as I sort out some niggling  problems with A.O.  tracking etc., I will go dual scope.

Pentax can produce some really nice lenses. Never tried them for astro work though. Still have a Nikon F2AS camera with lenses from about  35 years ago. Not used now. I use a Canon 5D now for ordinary photographs. But still wish to try out DSLR photography some day. One hurdle at a time EH!!!

I wish you  well ion you choices.

 Regards,

 Derek

[blueangel]

I ordered the QSI 683wsg about a day ago, but I am having second thoughts. I think I like the squarer format of the 690 vs. the 1120. It looks like the cleaner Sony chip would be better for longer exposures and fast refractors than the Kodak chip.

[Physopto]

You will have to do darks anyway. I doubt that you will see any difference then. It is a great ccd.

[perfrej]

I too would opt for real estate instead of noise figures. The KAF-8300 in a camera with good electronics (like QSI) gives excellent results. Personally, I never use darks but have tried it. The difference is not very large and I would rather take a few more subs and get rid of the noise that way.

The Sony sensors are interesting in their low noise and high QE figures, and I wish they would produce something bigger. When looking at how some people image, I can surely understand why they look at Sony equipped cameras. They hop from target to target and hope to bag more than one in a night. For best results, one have to accept that imaging takes time; sometimes much more than initially estimated. I can spend a month on a small set of targets and usually aim for 25-50 subs per filter (15-30 minute subs) and run two or three targets in parallel. A three-target list will take a month or two. Patience

/per

[Physopto]

That is interesting Per,

I have not thought of doing that, (not using darks). I have not been able to get that sort of imaging time in so far. But it gives me hope and a further aim to go for. I suppose it also comes down to cost. Bigger CCD chip bigger cost. One thing I have discovered for myself is that you need a lot of sub time to get the colours in your images. I keep trying.

You are completely correct though in my opinion, noise is not the be all and end all of a chip. The QSI cameras are excellent.

Derek

[Horwig]

Well, I suppose I should update my story, did not get my Lotto win, but went out and spent money anyway, a QSI 6120wsg from IKI, and what a lovely looking piece of kit it is.

First light was a while in coming, typical, but a nice image was eventually acquired:

This was lights and bias only, 300sec L, 60sec RGB, binned x2 on my Pentax 67 300 ed at f4

Trouble was, I couldn't get above about 49,000 ADU, so enquired of QSI, and eventually an answer came back that there had been a bad batch! Just by luck of being an early adopter I suppose.

So the camera is back with QSI, together with a couple of others from the UK I believe.

This is a second camera for me, I have as SX h35, and guess what, that had to go back to the manufacturer as well because of incorrectly set gain. On binned subs, I would get blooming on any pixel approaching saturation, even on very short subs.

Somewhere is a lesson, but I'm not sure where.

Huw

[Physopto]

Nice image.

I suppose with the way things are going to save money some manufacturers are skimping on quality assurance checks. I have had two QSI cameras and both are really great. Bad luck for you, a shame really. My images with the 683 and 583 are no blooming at 63,700  on Altinak with 1200 sec sub CLS filter.

As I said before nice CCD on the 683 and 583s

Derek