660 replies to this topic

[A. Viegas]

Matej, Could you please tell me the download time per image, Thank You.

Martin

The download time is less than a second.   I measure the download in my USB2.0 long repeater chain at around 2fps because I am downloading 3 USB cameras on the same USB repeater channel.  When I am using just the ASI 1600 the download speed is basically instantaneous.  Matter of fact, even with 3 cameras I cannot notice any meaningful lag in download, its basically a second or faster for a full frame, unbinned ~10mb of data.

Al

[entilza]

Thanks that's very good since right now with the DSLR and SGP there is some converison from RAW->Fit which delays the download and causes a CPU spike. Having native direct FIT is a nice benefit.

[FiremanDan]

Thanks that's very good since right now with the DSLR and SGP there is some converison from RAW->Fit which delays the download and causes a CPU spike. Having native direct FIT is a nice benefit.

 

I use APT, I had just been taking the RAW and converting to FIT in PI. 
I do like the idea of one less step in processing if the camera is native FIT! 

 

Does anyone know if it's true that the ASI1600 and 8300 have similar amp glow in their (light and dark) frames? Hearing about how bad the amp glow is with the 1600 is unnerving since my DSLR has no noticeable glow. But if it's something found in CCDs, specifically the one I was looking at, then that evens the score with that regard. 

[entilza]

Dan, Matej provided a 5 minute dark, if you want download it and drop it into DSS and see what you think. Compare it to one of your darks.

I see slight amp glow on the right which if not subtracted would stack on many integrations. Since it's cooled it should be easily subtracted though as it should be consistent.

[CounterWeight]

That is what I was wondering... if setpoint cooled and can be subtracted with darks. I wouldn't expect it to be a show stopper with shorter exposures unless it was really severe?

[FiremanDan]

Dan, Matej provided a 5 minute dark, if you want download it and drop it into DSS and see what you think. Compare it to one of your darks.

I see slight amp glow on the right which if not subtracted would stack on many integrations. Since it's cooled it should be easily subtracted though as it should be consistent.

I opened it in PI and ran the STF and compared to 300s of my T3i. 

Here is the STF of the 1600: 


Here is 800 ISO at 30c with the T3i: 


Here is 3200 at 30c with the T3i: 


I don't have a point. My darks look more "noisy" with no noticeable amp glow. 

 

The 1600 looks less noisy, but more hot pixels or cosmic ray hits. I am not sure how to tell the difference. 

[pedxing]

That's pretty noticable amp glow on the right side of the 1600 image.

It can be removed with darks, but will affect the SNR in that area.

I don't see any amp glow in your T3i images, which is in line with my experience.

The hot pixels in the 1600 image probably stand out more because of the lower noise overall.

[Jon Rista]

That's pretty noticable amp glow on the right side of the 1600 image.

It can be removed with darks, but will affect the SNR in that area.

I don't see any amp glow in your T3i images, which is in line with my experience.

The hot pixels in the 1600 image probably stand out more because of the lower noise overall.

 

It won't actually affect the SNR of the object signal. It will increase the total pixel charge in that area, which would diminish DR in that area. However, you gather object signal at the same rate regardless. If you gathered 5e- object signal in that area, and you had no amp glow, it would be 5e-. If you did have amp glow, then it would be say 5e- + 2e-, so 7e- total signal. Once you subtract the amp glow, you would be left with 5e- again. The only thing that changes as a result of amp glow is DR...but, amp glow is usually a very low level signal, a few electrons or so maybe. It's not really going to hurt anything in the long run. 

[andysea]

In my opinion the low read noise is the selling point of this camera. I would love to see lucky imaging done with it.

Wish list:  If they came out with a 24x36mm version of this CMOS sensor I would definitely jump on it!...or even an APS-H version.

Edited by andysea, 20 April 2016 - 02:48 PM.

[bigeastro]

Andy,

I believe you are correct and this is especially true for shorter focal length instruments. The actual pixel size is not quite suited for the middle of the focal length spread typically6 used by amateurs as is the new 16200 or the 8300 but the low read noise is attractive.

[fetoma]

Maybe ZWO should make cameras with the 8300 and 16200 chip.

 

If they could make a cheaper KAF-16200 chip camera with good cooling, no amp glow, and low read noise, it would fly off the shelves.

[PiotrM]

Maybe ZWO should make cameras with the 8300 and 16200 chip.
 
If they could make a cheaper KAF-16200 chip camera with good cooling, no amp glow, and low read noise, it would fly off the shelves.

They wouldn't be cheaper as those sensors prices are stable and likely wouldn't be better than cameras made by companies having years of experience with Kodak/TrueSense sensors. And CCD is generally going away and "soon" people will be using CMOS replacements for KAF-16200 and alike, maybe even this camera: http://qhyccd.com/QHY42.html

And due to CMOS sensors specific with built in ADC that is less than 16 bit as well as low read noise - it will be better (at least it is for current CMOS based cameras) to shot many shorter exposed frames. 5 minutes will seem "very long" in most cases. Even with Atik 314L+ I often just shoot at 3 min exposures. Spaghetti Nebula was an exception that even at 10min exposures was barely visible

Edited by PiotrM, 20 April 2016 - 03:48 PM.

[bigeastro]

I am not quite sure the market is ready to play taps for the Kodak/TrueSense sensors.

[AstroCatinfo]

Any narrowband images with the new ASI1600MM cooled?

[matejmihelcic]

I will capture nb images soon.

[Starsareus]

Thanks A. Viegas(4/19). But I may be amiss, I thought Sam said the only one that has access to the Chip was the uncooled camera?  

[FiremanDan]

Is it possible to post a calibrated light frame? 

[A. Viegas]

Thanks A. Viegas(4/19). But I may be amiss, I thought Sam said the only one that has access to the Chip was the uncooled camera?  

Sorry, but maybe I dont understand exactly what you are trying to do...  but from what i can see there are four ways to attach the camera to a scope...

 

1.  you can screw in a 1.25" barrel to the existing black ring you see in the photo

2.  you can screw ina c-mount adapter into the black ring

3.  you can remove the black ring and screw the camera directly into a filter wheel which as I said I think is about the same thread size as what you could screw a typical SCT 2" reducer into. This means you can screw this also into a 2" holder or hyperstar lens too

4.  you can remove the screws from the protective AR window and remove the ring and the glass protection for the sensor, exposing it...

 

I could be wrong but all the ASI cameras seem to have this same basic form factor...  and I think the threads are all the same in terms of attachments...  hence if you can look at an existing 174MM cool you can see if that camera can be adapted to whatever imaging reducer/flattener you need to attach.

 

Al

Edited by A. Viegas, 20 April 2016 - 08:16 PM.

[andysea]

Is the sensor not in a gas purged sealed chamber? How does this camera control condensation?

[A. Viegas]

Hi Andy

 

I believe there are desicant caps inside the chamber, but I do not believe that the chamber is gas purged.   I have not had the camera out long enough to detect any condensation, but I guess it depends on where you live and your personal history with condensation issues.

 

Al

[akulapanam]

Is the sensor not in a gas purged sealed chamber? How does this camera control condensation?

A gas purged chamber is a rarity across manufacturers.  I have never had issues with condensation in Dallas or Las Vegas although I can imagine it might be an issue in more humid or colder climates. 

 

Maybe ZWO should make cameras with the 8300 and 16200 chip.

 

If they could make a cheaper KAF-16200 chip camera with good cooling, no amp glow, and low read noise, it would fly off the shelves.

 

This is a much better camera than the 8300 in every sense.   At least 1/7th to 1/10th of the read noise, at least 1/10th of the dark current, similar to marginally better QE, much better dynamic range, and no RBI.  Will you need darks to eliminate amp glow?  Probably but many CCD cameras suffer from the same issue.

 

Keep in mind the KAF-16200 has been stuck in development for 5-6 years, and while it is the best of the Onsemi sensors and also a large frame, is way behind the times in technology. 

Edited by akulapanam, 20 April 2016 - 10:38 PM.

[andysea]

Good to know! I guess a user serviceable desiccant would be sufficient. I actually never had any issues with condensation either.

I'm actually not set on the 16200, I am just hoping for a larger sensor to get a bigger field of view with my RC scope.

[bigeastro]

Andy,

I am in the exact same boat. I am on the 16200 waiting list. If this thing pans out it is a potential real deal. However, we would be giving up that beautiful large field of view that we crave for our RC scopes. However, the pixel size is an issue due to the mis-match with 1500 to 2000mm fl instruments.

This thing looks perfect for 300mm to 1000mm?

[andysea]

It's  a balancing act. I would get an almost identical FOV with my RC at 1850mm and the Canon 6D or 1000mm and the ASI1600. The pixel  scale would differ only by about 0.11" so not a huge difference. I suspect that in the end the images would be similar.

[akulapanam]

I posted this in a thread of its own but maybe folks missed the purpose.  This simulator will give you an idea on image quality between two cameras. 

 

http://www.hamamatsu...gine/index.html