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ZWO ASI183MC-Pro: sweet spot for gain and temperature?

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#1 Jason_Lyman

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Posted 25 December 2018 - 03:57 PM

Hi All,

 

Merry Christmas!

 

Just got my first cooled camera and can't wait for some clear skies.  Figured I'd drop this question here in this forum.

 

For those who may already have this camera and have experience with it, have you found a sweet spot for the gain and temperature setting?  Just looking for a good starting point for when I get out with it.

 

Thanks!

Jason


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#2 dapalmer

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Posted 25 December 2018 - 05:02 PM

Congratulations! I also got one for Christmas. I even got a filter wheel. However, I will have to wait for the filters as the budget hit its limit.

 

Obviously I am not prepared to answer your question as I am in the same boat. 


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#3 dmdouglass

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Posted 25 December 2018 - 05:31 PM

Well, i too am "new" to this, but i think you will find some good suggestions in this thread.....

Be sure to study the "tables"....

https://www.cloudyni...xposure tables


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#4 Jason_Lyman

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Posted 25 December 2018 - 05:59 PM

That's a very good thread. I'll definitely utilize info from that one.

#5 Gipht

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Posted 25 December 2018 - 07:10 PM

With my ASI183MM - pro, and my 70mm f/4.8 apo refractor I  will use a gain of 53 unbinned for 4 minute exposures on average.  If I am using my reflector telescope,  10" at f/4,  I may go to a gain of 160 and binx2 for 30 second exposures.  This helps offset the flexure  and  poorer tracking that occur  with the large reflector.  There is a lot of flexibility in what you can do.

 

As far as temperature, in the winter time I try for -30C as long as the night is not too warm.  In the summer time, I switch to -15C as that is all I can achieve without overworking the cooling motor.

 

Part of the fun of the new camera is finding out what fits best for you.  Good luck!


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#6 Cfreerksen

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Posted 25 December 2018 - 11:03 PM

I have been using gain 100 at -10 degrees. I have not tried any other settings so far. I'm trying to keep the variables to a minimum. Exposure about 15 to 20 seconds at f/2 Hyperstar and 90 seconds to 3 minutes at f/7.

 

Chris



#7 HAlfie

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Posted 26 December 2018 - 08:15 AM

Hello, I've been looking for the same answers recently wink.gif !

I strongly suggest you to look into this very interesting topic : https://www.cloudyni...ad-asi-qhy-etc/

 

Here are my conclusions so far after hours of research on several forums.

 

Regarding GAIN values : 

  • Try to stay within the  54-178 gain range and more likely between 54 and 111 range. Below 54 gain, you could have banding issue and above 178 gain, the amp glow could become a problem despite a good calibration.
  • LRGB : Gain 54 and exposure of 60s, 90s of 120s.
  • Narrowband SHO : Gain 54 or 111 and exposures length of 5min (with short focal ratios < 5 or 6) and up to 10min  (with longer focal ratios > 5 or 6)
  • If you need shorter exposures because of your mount quality guiding limitations, you could try a gain of 178 but ideally with exposures length shorter than 5min (like 4 or 3 minutes).

The sensor doesn't have the same behavior as the ASI1600MM/QHY163M (with its bigger pixel size of 3.80µm which seems to be easier to use) where you can push the gain much higher for shortening exposure lengths in narrowband for instance.

Though, with short focal ratio < 400mm, the smaller 2.4µm pixel size of the 183MM will give you nice details and the AR coatings on the senror will not have reflection issue on bright star contrary to the 1600MM.

 

 

Regarding TEMPERATURE Values :

  • It is recommended to stay within 10%-90% power range. Below 10% power you can face some issues while trying to keep the temperature at a precise value. Above 90% isn't recommended as well unless you want your camera to face death a little bit earlier than expected tongue2.gif  . Who knows, better to be careful.
  • As the camera can "really" do -35°C below ambiant temperature it can be interesting to have 2 settings: one for summer season and one for winter season.
  • In my case : -15°C is the "summer" temperature setting and -25°C is the winter temperature setting.

On last thing, regarding the cool down or warm up durations. I think it might be interesting to use "safe values". Such as 15min or 20min to cool down and between 20min to 30min to warm up but probably other people will tell you not to worry regarding this matter. From my perpective, if you want that your camera last longer without frost issues, using some safety margin values  can be a good approach because I remember the duration of cool down or warming up of the APOGEE (=high end CCD brand) with the older KAF8300 which was around 30min each.

 

Hope this helps and clear skies smile.gif


Edited by HAlfie, 26 December 2018 - 08:16 AM.

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#8 Jason_Lyman

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Posted 27 December 2018 - 02:29 PM

Good stuff. Thanks!

#9 BobInTexas

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Posted 07 April 2019 - 01:40 PM

 

 

Regarding TEMPERATURE Values :

  • It is recommended to stay within 10%-90% power range. Below 10% power you can face some issues while trying to keep the temperature at a precise value. Above 90% isn't recommended as well unless you want your camera to face death a little bit earlier than expected tongue2.gif  . Who knows, better to be careful.

 

What does this comment mean and how can you tell what you're currently set on?  Are you just measuring the current and dividing that by the 3A max?



#10 Jon Rista

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Posted 07 April 2019 - 02:03 PM

What does this comment mean and how can you tell what you're currently set on?  Are you just measuring the current and dividing that by the 3A max?

Usually the software will report cooler power as a percentage. With the ASI cameras, the cooler uses a PWM that has a minimum pulse, which is just a little under 10% power. So you cannot actually reliably cool to a specific setpoint under 10% power. You also need to make sure you have some wiggle room for power to be adjusted to maintain the setpoint, and usually a buffer of ~10% power is recommended for that. On the high power end, that means you should never go over 90% to ensure you have that buffer there to allow power to fluctuate as the setpoint is maintained. Usually, things cool as the night wears on, so this means if  you start at 90% power, by the time the night ends you should be lower than 90% power. Further, it means if you expect the night to cool, you might want to start the night off with your cooler around 20-30% power so that by the time the night ends, you are not below 10%. 


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