Tuesday, September 4, 2012

M57

Tonight, I wanted to take pictures of M57 - this time without the focal reducer. Setup was quick! I then tried my luck (again) with PHD, but this time, during calibration, the scope did not move at all. I didn't bother to try to figure out what it was, but started taking pictures. I wanted to compare slower (30 sed) exposure time with longer (2 min),

Here is the result from 30 sec:

And here is the result from 2 min:

This is after super simple Background offset and DDP in Nebulosity. I'm sure that I could correct the background in the second picture. But there isn't more detail in the second picture!

For 30sec, I had to throw away 10 (20%) of all pictures. For 2 min, it was much higher: almost 50%!! Almost all "bad" pictures were "shaky" - I wonder where this still comes from. If the scope wouldn't be able to track properly, all pictures would be bad. But that some are bad and others aren't makes me believe that there is something else.

So, it seems as if this nebula is bright enough that it can be captured with just 30 seconds very well. Furthermore, it's sharper with the 30 second exposures. Maybe I should try it to do this with eyepiece projection (and maybe higher ISO to keep exposure times short).