Could a similar method be use to create a Flat library using an ASI2600 or ASI533 color camera? I am new to this hobby and think of all sorts of questions I dont seem to find answer for. To my amatuer mind it would seem as long as camera temperature, gain, and exposure times were the same, it should work.

I have just bought the axiair plus and the axi533 to go with my new WO GT81. Will prepare a library of darks following your advice. I need to get Pixinsight. QUESTION… do you stack using DSS or in Pixinsight? Cheers Mark

@@markwright748 congrats on the setup; sounds awesome! I stack in Pixinsight almost exclusively, though I know folks that do DSS or AstroPixelProcessor with good results

@@WindyCityAstrophotography Thanks very much.

@@WindyCityAstrophotography Hello again I’ve built a dark library of 450 exposures ranging from 2 seconds to 2 minutes. 9 different lots of exposure times, 50 images for each exp time. All stored on my asiair plus. When transferring to my Laptop via Wi-Fi I have 900 files ; 450 GIMP and 450 very small (15k) JPG files as ll

Indeed! Glad it was useful!

Hooray! Glad to hear it!

What do you name your dark flats since ASIair does not have a name for them?

Glad it was helpful!

Oooh yeah if/when I get another astrocam the complexity will definitely go up!

@@WindyCityAstrophotography I definitely found my life being easier with image train copies specific to the camera to transfer between. 😊

Thanks very much! Correct, 2 minutes is usually my max for narrowband, though I have seen some users go longer. That is usually at Gain 139. I also usually do half of the exposure time for OIII (and double the number of exposures); it seems to help mitigate the light pollution gradient which is always most noticeable with that filter. I use plan mode to a fair extent. Hoping to put together a video on Plan Mode at some point, but will need a clear night...😬

I agreed. Fantastic

Oh man, 120" is about my max 😆

Glad it was helpful! I don't do a lot of RGB imaging since I'm in very light-polluted skies, but the lower gains help keep the stars under control with RGB imaging since so much more light is hitting the sensor. I will say I just completed a run of broadband images at Gain 139 and the star bloating wasn't too bad, but I was also imaging a dark nebula so I needed as much signal as possible. With a slower scope than the RASA or a camera with deeper wells than the 1600MM, though, you could almost certainly get away with higher gains even for broadband.

I need to take another look at that for sure! Thanks for the reminder.

A great question! I haven't dived into autoflats yet, and this is the main reason I am hesitant to do it. I would imagine within half a second is close enough, though. Maybe give it a shot and run the integration several times with different dark flats and see? During my next stretch of cloudy nights maybe I will do that and report back. I would also like to test autoflats side-by-side with my standard 5-sec. Because if autoflats work, then awesome!

@@WindyCityAstrophotography Thanks for the response... and greetings from Naperville. Most of the time using the same scope results in an identical auto flats exposure time for each filter assuming you set your flats panel to the same output level, but I have noticed it can vary slightly. So, I have found that I do have a growing dark flats library. On the positive side, running the auto flats in ASIAir is fast and easy which matters at 3:00 am. :) Will let you know if I learn anything more on an appropriate threshold for the dark flats, but your thought of give or take 1/2 second sounds reasonable. Thanks again!

Dark libraries are only effective for cooled astrocams because then you can set the temperature you want the chip cooled to so from the camera's perspective the temperature is the same every time. Assuming you have set a temperature that is achievable in every season (camera can get it cool enough in summer and the air temperature doesn't get cooler than the set temperature in winter) you should only need one set. But I usually have a set for -10C or 0C for those warm summer nights where the camera can't cool enough. These cameras can only usually achieve a 35 or 40 degree drop below ambient. So if it's 30C out on a hot night I almost certainly can't achieve a -15C setting on the camera

@@WindyCityAstrophotography I too am confused about this. I "think" you are saying that the "absolute/actual temperature" of the sensor does not determine the noise characteristics of the sensor, but rather the temperature differential. Is this correct? Otherwise you would have wide swings between the sensor temp based on ambient temperatures,

@@johnrsims43 I think you might have it backwards. When I set my camera to -15C, the chip is cooled to 15 degrees below zero Celsius. The camera doesn't know the ambient temperature of its surroundings, so whether I am taking darks inside on a cloudy afternoon or imaging the Heart Nebula on a night when it's 3 degrees Celsius out, the camera chip is the same temperature. So that temperature setting (-15) is what the darks and lights need to match. It isn't relative, it's actual. That being said, cameras can only cool so much below ambient (just based on the limitations of the cooling mechanism, not the camera's knowledge of what ambient is) so occasionally on hot summer nights I can only achieve -10 or 0C (actual, not relative) so I need to have darks that match that temperature as well. The temperature of the chip is THE determining factor in the noise characteristics, whether it was that temperature on a cold winter night or on a hot summer evening, as long as the chip was the same temperature both times the noise characteristics would be the same and a set of dark taken at that chip temperature would calibrate correctly. Does that clear it up?

@@WindyCityAstrophotography Hi Windy City: Thanks for the reply. Your explanation is most appealing to my limited understanding of camera cooling systems. My confusion stems from the constant reference to "Ambient Temp" when ever the sensor temp is discussed. I've never seen it expressed as "actual temp". For instance, the following is from the ASI 2600 user manual: "Cooling system can be set to a minimum temperature of 35 °C below ambient temperature. I had been reading that as a "brag", but now guess this is an expression of the cooling system limitation. In other words, if the ambient temp is 35 C, the minimum temp the cooling system could achieve would be 0 C. Or if the ambient temp is 23 C the minimum temp that could be achieved would be -12 C. I do find that to be quite remarkable. Thanks for your clarification.

A good question, but I think that'll be something that the integration software (like Pixinsight) will be able to do. For something like livestacking in AAP it is just using the selected dark frames. With the new 2.0 update, though, and the stacking capability it is possible; I'll have to look into it

@@WindyCityAstrophotography Thank you!