Quote:
Originally Posted by mike geisel
Hi, thanks for the replies. Glen, I was interested in your comment that the 1600mm-c would be fine at anything below 10deg. I always try and get it as cold as possible, but I also read somewhere recently that it was more important to keep the temp constant. At the moment I have it set to -26deg but maybe in the hot weather I should be more realistic and set it to something like -14deg. Also one of my biggest problems with astrophotography is patience!. 3 hours total on this was all I could bear. Your suggestion of 3x100 subs at 5min would drive me insane!
Malcolm, thanks also. I have my gear permanently set up and aligned in an observatory and thought the polar alignment was pretty good, within a few arc minutes. But I think I will revisit this and see if I can get better. I use Sharp Cap pro for capture and it has an automatic apply darks feature, but I think the dark files need updating, so I will try that. I have been lazy and slack and not doing flats and biases and up until now have been getting away with it, because subs have been fairly short, usually 60 seconds. I plan to start using these calibration frames soon. Perhaps the lack of flats is the reason for the background streaks? I do alignment usually in Nebulosity 4 and at the moment only use pixinsight for modified hubble colour correction. But I hope to learn more about pixinsight over the next year, (New Years Resolution??) Thanks guys
Mike
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Mike I was referring to imaging at -10C with the 1600mm-c in summer. It is near impossible to get down to -20 or less on a warm summer night. A Delta T of 35C from ambient can be difficult for that small Cooler chip and fan. You will probably find the camera case starts to heat up, a sure sign it cannot shed heat. You could install a small booster fan to increase airflow over the case, I did that a few times in mid summer. As to building more data, consider returning to your target over multiple nights, as this can be the only way to build sufficient signal to improve your image. Of course, imaging over multiple nights means that you need the skills to return the scope to exactly the same spot in the sky with camera alignment to match. In an observatory, where your setup can remain untouched, this is pretty easy, even without Plate Solving. However if your tearing down each night it can be difficult, but Plate Solving can help alot. Even if your sub alignment is slightly out you can still align them with DSS if they are close, you may need to crop overlaps slightly but it can work. Obviously full plate solving as in SGP or other sequence automation software, makes it easy, but increases the complexity of your operation, at least until you have it all working well.