running sgp 220.127.116.11 and using a SBIG ST8300, I have cool down set to -20C and letting camera run cooling for at least 30 minutes before starting sgp.I set up a sequence and it starts but has message at bottom of screen stating waiting for camera to reach cooling temp…this has sat there for at least 45 min and I finally kill session…Why is this happening and what can be done to get imaging sequence to start?
What is the ambient temp? If it’s too hot outside then the camera will
never reach the -20C set point. Other than that, it’s hard to know what’s
going on without a log file. Can you post a log with dropbox or another
file sharing service?
Pleas see this post for further instructions on how to ask for help:
is there a way to bypass that so that the sequence of image captures just starts?
sg_logfile_20160809195613.txt (358.5 KB)
The message that pops up should give three options: continue the sequence, abort, or delay start. Just choose the option to continue even though the camera temp isn’t set yet. However I think the best practice is to set the temperature so the camera can actually get there. If the camera temp can’t reach where you set it then the cooler will be running at 100% which isn’t good for the camera.
wasn’t a pop-up message, shows at bottom of window (basically like info or status) so would have to adjust temp setting according to what ambient temp is? If I set in profile as -10C in 5 min, shouldn’t that tell it, 10 degrees below ambient?
Thanks for the Log. At this point Jared or someone will need to take a look as I’m not sure what’s happening.
However I don’t think you understand how cooling works. If you set the temp at -20C the camera is trying to get to -20C. Your camera has a max delta T of about -40C, meaning that no matter what the air temp the camera can get -40C max below that air temp. So if it is 25C air temp, the coldest the camera will be able to get to is -15C.
So if you set -10C in 5min in the profile, that means the camera will try to get to -10C in 5min regardless of what the air temp is. It does NOT mean -10C from the ambient air temp.
I am fairly new to using tec cooling camera, and brand new to sgp, so I should adjust the temp (I assume in profile) depending on what the air temp is at, am I getting that correct?
The point of cooling a camera is to reduce the noise from the CCD sensor, this increases as the temperature increases. The best operation is when it’s cooler.
The CCD temperature needs to be the same for all the exposures, both all image frames and all the calibration frames - dark frames at least - so that the noise in all the frames has the same magnitude. That’s the same absolute temperature.
The camera tries to do this by cooling to a fixed, controlled, temperature but there’s a limit to what it can do, this is the delta T that Jared mentions.
If it’s hot and your camera can’t cool enough then set a higher set point temperature but you will also have to collect a new set of dark frames at this temperature. Personally I run my ATK8300L at -15C because I can reach that all year round in the UK.
Here’s a specific example:
I use an SBIG ST-8300M. Here in Central Texas our current nighttime temperatures are in the mid-80’s F (about 30 C). My ST-8300M will do about 30 C down from ambient so I am currently setting the SGP temp control box to +5 C, the lowest temperature at which the camera reliably maintains regulation.
I personally don’t set the cool down temperature in the equipment profile, I prefer to set it in the pull down temperature box from the toolbar since my requirements (or possibilities) will vary with the weather.
You might want to check out “Camera Temperature Control (TEC)” in the SGP help file.
Clear Skies (and lower temperatures :>)
Ambient temp has nothing to do with the temp settings in SGP. -10C means that the camera will attempt to hit -10C regardless of what the ambient temp is. However as BobT mentioned this isn’t always possible as the camera can only cool so much depending on the ambient temp.
But the temp you set in SGP is absolute.
Thanks guys, I am just trying to learn the program so sure I will have questions from time to time, great help here to help me understand it better