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Old 05-03-2009, 08:36 PM
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Qsi 583

Just wondering what some of the CCD guys think of this camera?

I am looking for an alternative to buying an Sbig STL11,000. They cost way too much, but this camera seems to have the goods. Mind you it does only have a 2" nose cone and the positioning of the 1.25" filter wheel would seem to suggest that light might well be slightly vignetted.

Thoughts?
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Old 05-03-2009, 10:04 PM
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Paul,

I am not sure these are really all that comparable to one another in specs to then compare them by price !

The QSI uses the 8mp KAF8300 sensor - its a 4/3rd sensor (just smaller than APSC)
The pixel size is 5.4Ám
(btw used by some of the older Olympus DSLRs - in colour)

The STL uses the 11mp KAF11000 sensor which is a much larger chip and has 9Ám pixels and twice the well depth.

There are so many other differences its a bit like comparing apples with pears

I note QSI claim 70db dynamic range yet Kodak who make them claim 64db ? Maybe its when they are chilled - or maybe its marketing ?

I cant imagine you would get any vignetting with the QSI and I am sure its a good camera - Apogee and FLI use the same chip too.
What is their interface like and is the camera supported by the software packages you would like to use ?

Cheers

Rally
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Old 05-03-2009, 11:26 PM
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The QHY9 uses the same chip (KAF8300) and would be a lot cheaper.
However pixel size is only 5.4x5.4.
They do say it will do up to 4x4binning though.

http://web.aanet.com.au/gama/index.html
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Old 06-03-2009, 07:44 AM
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I'd say it'd be an exceptional camera. They also have a built in off axis guider option which makes it the same only better than an SBIG camera (self guiding goes through the filters and this is a severe limitation - ie blue filters require longer guide exposures and Ha and O111 and S11 are virtually impossible to guide through with self guiding).

I have the FLI ML8300 (the same chip). There is also an Apogee U8300 using the Alta body (I have an Alta U16M). Both are sensational.

The 8300 chip is a marvel. A very cheap and perfect chip that is highly sensitive and low noise. A modern chip.

Well depth is overrrated. Although you will notice some brighter stars tend to be a bit haloed or wider.

The STL11 is a fabulous camera and a proven performer. But it is not as clean a chip as the 8300. The 11002 can have vertical lines sometimes caused by hot pixels and it is way noisier than the 8300 which is extemely low noise - so much so that darks are almost optional at low temps.

The main difference is FOV. The 11002 chip gives wide FOV compared to the 8300 on the same telescope.

I think you should start your evaluation from the image scale you wish to image at with your existing telescopes and work from there.

Wodaski has a free CCD calc that makes this step easy. It gives sample images with different CCDs/scope setups so you can see in an instant what the different setups would produce as well as ARC/Sec/pixel computations.

That figure then should be matched to your seeing conditions.

.66 arc secs/pixel is a good figure so your camera is sampling the scene accurately and not undersampling. But if your seeing is typically 3 arc seconds then you could go to 1.5/arc sec/pixel (half your typical seeing is often quoted as a guideline).

In my case I got the 8300 chip so I could get more zoomed in higher mag images from the same scopes I use with the 16803 chip camera which gives a wider FOV.

I doubt you would be disappointed with that camera. I have not heard from anyone using one although I have seen images from that brand and they seemed as good as any other manufacturers camera.

The QHY9 is probably not in the same league as electronics are important and from other QHY cameras using the same chips as their competitors seem to produce not as good results as the electronics are not as good.

FLI ML8300 would be the best of them all with superior cooling and all the features FLI have put into it. But it is more expensive and does not have an internal filter wheel.

You want USB2.0, good and fast cooling (50C below ambient at least - my FLI does 65C below ambient and the chip is virtually noisefree at -35C, it gets there in 2 minutes flat, Apogee does 50C below ambient or better but takes 30 minutes to get there), durable shutter, fused silica CCD window, no cover slip on the chip (Apogee do this standardly), fast download times, internal buffer (really was sick of SBIG cameras needing to repowerreboot all the time if there was a problem with the connection - Apogee and FLI cameras are independent of the computer once started - a really good feature), availability, accesories available, reputation, after sales service. Does it come with a case? Apogee and FLI do not, SBIG does.

Greg.
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Old 06-03-2009, 04:18 PM
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Greg,
The electronics in the QHY-9 is as good as any other design and vise versa.
As long as you understand how the CCD camera works, and how you obtain the data from it, your naughty to make suggestive answers.
The ADC controllers, and main comms, are virtually the same. Designers go for low noise ADC chips, as well as fast sampling speeds. You will be suprised to know that they will most likely have the same chips inside.
Noise is the only added drawback you get from different camera manufacturers.
This is introduced by not taking proper precautions, or skimping on, as you say, the electronics. Assumption is never an asnwer, but detailed specifications are. What you should grasp is just how little circuitry is required to provide an image. Of course if you add a power supply, and guider circuitry in the same box, then of course the whole thing looks more complex. This is why the SBIG cameras are so big. They do pack quite a lot of electronics in it. US ROBOTICS on the other hand use much less, as also does Starlight Xpress, etc. But this is still irelavent, as its the specifications and displayable performance that counts.
Cooling is extremely important, i agree here. But these days, nearly every camera will do -50 Deg Delta off ambient. The QHY-9 will do it in 5 minutes, the newer Sbigs should be right there too, but that doesnt mean everything. How low is the readout noise, what is the thermal noise within the camera, download speed, etc.

Paul,
StarlightXpress, QSI, ATIK, QHY make absolutely great products, as does many more manufacturers.
I really recommend you look at your budget, and then look at the quality of images produced by the model you want. Just make sure you compare the imagers behind the work as well. Ive seen some really good shots from some cameras, but then seen really bad ones with different imagers processing them, so take experience in processing into account.
Software and drivers is another thing to look at. Does it have all the drivers you want, like Maxim, Ascom etc.
You wont go wrong with the 8300 sensor, but just be warned, it really does have a low full well depth.
Personally, i prefer the 9000 sensor, as it has 110,000 well depth, 64% QE, and 12 micron pixels. But thats me..

Theo
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Old 09-03-2009, 07:13 AM
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Hi Theo,

I have never used a QHY so yes I can't really comment. The only comparison I was aware of was between the Starfish guider an the QHY guider both of which used the same chip. The QHY based on internet samples of guide images from both was a lot noisier. That was my only base for the comment. Perhaps they have improved their electronics since then as any developing company usually does over time.

Perhaps there are reviews of both from different sites - maybe Cloudy Nights or even Anacortes or OPT.

Greg.
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Old 10-03-2009, 08:00 AM
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Greg, the Starfish has cooling that might explain why there might be less noise in the images you have seen from it. The Qhy5 and its rebadged counterparts do not have cooling.
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Old 11-03-2009, 04:23 PM
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Hi Fahim,

There is a cooled version of the starfish, I had one. I was referring to the non cooled version. There was a very significant difference in the noise levels to the QHY.

Not sure where I saw the comparison now - it may have been on the Starfish home site (Fish Camp engineering).

There is no doubt in my mind electronics varies a lot between manufacturers.

How else do you explain Starlight Express cameras having virtually no noise from chips used in other common brands where they are quite noisy.

I can't comment on SBIG versus FLI and Apogee in this regard as SBIG currently do not sell cameras with these chips in them but I would expect both the Apogee and FLI to be considerably better.

To prove the point Mike S could post a 10minute dark from his PL11002 and I could post a 10min dark from my earlier STL11 and I suspect there would be a difference. But then again who knows - perhaps its all marketing hype.

Greg.
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Old 11-03-2009, 05:06 PM
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Greg, the electronics wont produce that sort of noise. It is inherent to the sensor. Its the sensor that emmits the noise. Unless your heating the sensor, at ambient temps, both cameras will draw peanuts of current/power, so extra sensor noise wont be introduced.
Software on the other hand is different. You need to compare with the noise reducing drivers/software available. It drops the noise to a point where you would think there is cooling at times.
These drivers are specifically from Astrosoft only (Included in the drivers diek), but many dont load those specific drivers, or cant because of incompatibility to the software used (PHD etc)..

Theo.
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Old 11-03-2009, 05:24 PM
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I like using the (selectable) fast download speed of 12MPPS which gives a lightening fast 1 sec full frame download time at bin 1X1 of the 11K chip, only offered in FLI cameras, so this is not the lowest noise capability of the camera actually, that is acheived by downloading at the slower and slightly quieter speed of 1MPPS (12sec full frame download time)....but I am impatient.

Here is a minimally compressed jpeg file of a full frame dark taken with my FLI ProLine 11002 (KAI11002 chip) warning 8meg file:

http://upload.pbase.com/strongmanmik...88167/original

Mike
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Old 11-03-2009, 08:05 PM
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You need to check that it still downloads at 16 bit resolution at the 1 sec xfer speed.
Manufacturers place either a dual 16/12 bit ADC or 2 ADC chips where 1 is for 12 bit (Fast download) and the other is 16bit (For normal download).
This is a technique used to increase speed.

These sort of setup's will be used more and more in the future.

Addition: Brute force Speed is also used too, and as said, noise becomes the weakest link and suffers here.
For some images ive seen using high speed, you really need to look to see that noise too.


Theo

Last edited by Gama; 11-03-2009 at 08:26 PM.
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Old 11-03-2009, 09:56 PM
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Quote:
Originally Posted by strongmanmike View Post
I like using the (selectable) fast download speed of 12MPPS which gives a lightening fast 1 sec full frame download time at bin 1X1 of the 11K chip, only offered in FLI cameras, so this is not the lowest noise capability of the camera actually, that is acheived by downloading at the slower and slightly quieter speed of 1MPPS (12sec full frame download time)....but I am impatient.

Here is a minimally compressed jpeg file of a full frame dark taken with my FLI ProLine 11002 (KAI11002 chip) warning 8meg file:

http://upload.pbase.com/strongmanmik...88167/original

Mike
Here is a 10 minute bin 1x1 -30C (I only have a 15 min -35C and besides -35C is not a temp you can ordinarily achieve with an STL, usually only in mid winter, in summer you may only get -15 to -20C and it is a lot noisier at those temps).

http://www.pbase.com/gregbradley/ima...92938/original

All I did was hit auto levels in PS to make the dark visible (otherwise the image was jet black as with any image before levels).

As you can see the FLI is way less noisy, same chip - KAI11002 class 2.

What's causes the difference? FLI claims it is superior electronics.

Also the FLI PL11002 is USB2.0 versus USB 1.0.

A pretty convincing reason to get the FLI don't you think?

Greg.
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Old 11-03-2009, 10:09 PM
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Also to show the comparison and validate FLI's low noise cameras a dark at -35C 1x1 10 minutes from my Microline8300.

I did exactly the same processing (autolevels only in PS and saved as jpeg no compression) as I did for the dark from the STL11.

http://www.pbase.com/image/110093020

It seems almost identical to Mike's Proline 11002 dark. The FLI electronics/firmware account for a large difference.

My Apogee camera is also very noise free although not quite as noise free as the FLI.

Also I can get -35C all year round. In winter I imagine the camera would go to -45 to -50C possibly lower. It seems to do -60C below ambient.

As you can see there is more to camera manufacturer choice than simply the same chip.

Greg.
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Old 11-03-2009, 10:20 PM
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Thats some pretty strong evidence to support your argument Greg. I agree, the electronics can add a lot of noise in the down loading of images.

Ciao Mark
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Old 11-03-2009, 10:28 PM
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Now I can see why you thought the FLI's were so much better than the STL11K, Man what a difference and I wasn't even at the slower lower noise download speed, I might have to try using the slower download speed?

Yes the PL11002 dark looks very similar to the 8300 dark, maybe even the 11002 is slightly better?...something I didn't expect. What download speed are you using Greg?

I came from Starlightxpress Sony chips that have virtually no hot pixels and very low noise, they simply do not need darks, so I thought my PL11002 was noisy actually, now I feel better, the STL chip looks like a snow storm

Mike
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Old 11-03-2009, 10:34 PM
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Greg, you have to understand noise of a CCD chip. "Noise" is random. If you get the same pattern, then you have NOT introduced any noise from the electronics.
If electronic noise was the main culprit, then its NOT predictable, as it can vary at any point and any temperature.

Cooling has a huge effect on sensor noise, this is why they use liquid nitrogen to cool the sensor, and not the whole camera
Even a -10 deg level is huge. Sbig darks, FLI Darks, etc, will have low noise as long as its cooling is great.
This is where FLI is a leader at. To get -65 Delta is a huge step, and remember what cools one side produces heat on the other.
Again, here is where you pay for you toy. It has to dissipate that heat without passing anything into the sensor side.
They dont make the cameras solid for no reason.

Theo
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Old 11-03-2009, 10:39 PM
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Mike, your naughty to compare the images like that.
Well, im naughty too as i also have done that too.

Theo
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Old 11-03-2009, 10:41 PM
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Quote:
Originally Posted by marki View Post
Thats some pretty strong evidence to support your argument Greg. I agree, the electronics can add a lot of noise in the down loading of images.

Ciao Mark
You are correct here, but the manufacturer normally provides this and much more data to you.

Theo
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Old 11-03-2009, 10:44 PM
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What i would like to see is a CCD sensor that has liquid nitrogen inside itself. This way the sensor is always sub freezing cold.

Theo
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Old 11-03-2009, 10:55 PM
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Quote:
Originally Posted by Gama View Post
Greg, you have to understand noise of a CCD chip. "Noise" is random. If you get the same pattern, then you have NOT introduced any noise from the electronics.
If electronic noise was the main culprit, then its NOT predictable, as it can vary at any point and any temperature.

Cooling has a huge effect on sensor noise, this is why they use liquid nitrogen to cool the sensor, and not the whole camera
Even a -10 deg level is huge. Sbig darks, FLI Darks, etc, will have low noise as long as its cooling is great.
This is where FLI is a leader at. To get -65 Delta is a huge step, and remember what cools one side produces heat on the other.
Again, here is where you pay for you toy. It has to dissipate that heat without passing anything into the sensor side.
They dont make the cameras solid for no reason.

Theo
You are quite right Theo, best to compare shots done at similar sensor temp but when you can go to 61.7C below ambient or better (best delta I have measured in daytime) -35C is so convenient as a year round temp setting...and you can see what it does. I must try a dark at the slower download speed and see what difference there might be..?

Yes the ProLine is a veritable brick, with three cooling fans blowing air over cooling vanes, to get these impressive cooling specs.

At the end of the day we take these darks for a reason so I guess as long as they match your lights accurately you can get good results regardless...just nice to know you have such great raw uncalibrated data to start with ...bluddy want to for a $10 000 camera

Mike
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