I am using the sub-exposure calculator for the fisrt time and I have a several questions.

1) What is the Temperature of Dark Signal?
2) The discussion section indicates that I should perform the above calculations for different filters at binning levels that I am using. Should I determine Gain and RON for each of these combinations or are these constants for all binning?

I am asking these questions becasue I generally get noisy color images with my AP155EDF/ST10XME with 5 minute 2x2 binned subexposures at -5C (I live in Arizona about 30 miles NE of Phoenix, I doubt that I will be able to do much better than this with water cooling in the summer). Incidentally, I measured my RON to be about 10.6 and a gain of 1.36.

Don

Don,

quote:

1) What is the Temperature of Dark Signal?

You should use the temperature that corresponds to your cooler setting. Multiple entries are shown so you can see the impact of changing temperature

quote:

2) The discussion section indicates that I should perform the above calculations for different filters at binning levels that I am using. Should I determine Gain and RON for each of these combinations or are these constants for all binning?

Gain and RON are determined by hardware and are fixed so you can use the same values for other binnings. Color filters may result in high sub-exposure requirements to meet the noise requirements. That being said, you may elect, as many do, to keep color exposures less than optimum and deal with the noise post processing using appropriate noise reduction/blurring techniques. Of course for optimal resolution, blurring should only be done in LRGB combines.

BTW, when I had an ST-10XME, I was able to get to -20 in Tucson using water cooling, a 45C differential. With the Finger Lakes IMG-6303 camera's air cooling only, I now run at -25C year-round due to its 55C differential.

John:

I guess then that the only independent variable that can be changed that can account for the binning differences is the test exposure time? Correct?

Incidentally, the cooling on the ST10XME was never an issue when I purchased the camera as I intended to sit with it all night anyways. However, since I purchased the Paramount ME (that you recommended to me) and the use of CCDAutoPilot has completely changed the way I work. Since I operate the mount remotely, tending water cables is a major pain and I have yet to become brave enough to route them through the mount. I guess a new camera with better cooling is in order.

Don

Don,

Yes, that is correct - exposure time is all you got

Well, there is a way to run water lines external to the mount. Check out the images here:
http://www.hiddenloft.com/equipment.htm
for some ideas on how to run them. I ran unattended imaging for a long time with this water line routing without incident. The only wrinkle in the system was I had to start the chiller along with everything else

I used this chiller:
http://www.hiddenloft.com/cooler/RAGcooler.htm
but others have had good luck with aquarium coolers at a lot lower expense.