Yesterday I tried to collimate my telescope but ran into problems. So I asked Mirko Boucsein from the local observatory if he’d like to help me, and he suggested to meet me in Darmstadt.
After successfully collimating the telescope (which is a matter of minutes once you’ll get the right tools and the hang of it) I asked him if I could try some “Live Composites” using my Olympus E-M10 camera. “Live Composite” is a term invented by Olympus which does some stacking in-camera, taking one base image and then only adding lights (plus one dark frame in the end to compensate for noise). Mirko wanted to get some photos himself using the observatory’s biggest telescope, and accepted to have my camera mounted piggyback to the big tube and mount.
First he pointed the scope to Deneb, and the North America Nebula (NGC 7000), and my camera took 14 photos (of 60 seconds each at ISO 200 and f/2) which resulted in one raw file and one jpg:
After doing that he wanted to get some long exposure shots of NGC 6946, better known as the Fireworks Galaxy. So he programmed that into the mount’s GoTo system, and the big scope went straight up to our zenith (the point right over our heads) to track that one. Here I took 45 exposures of 60 seconds each, which the camera again stacked into just one raw and jpg file:
You don’t see the nebula and the galaxy in my photos which I took with the Panasonic Leica 25mm/1.4 lens. First this is a very wide angle, and those nebulae and galaxies are small (in fact they’re huge of course, but I mean a small angle in my photos here). Plus they are also faint, and since I didn’t use any filter against the light pollution (you clearly see Darmstadt city lights in the second photo), I had no chance to get anything like that. Plus my camera isn’t modified to allow h-alpha and other wavelengths to even reach its sensor.
What you do see in both images were airplanes flying straight through my frame. This you can’t get rid of if you let the camera do all the stacking “live”, while taking the image – you’re much better off with manual stacking if you want to avoid those.
But still – these were my first two astrophotos using a tracking mount which was even guided by a third camera, and PHD on Mirko’s Windows laptop. So it doesn’t matter if your exposure time will be 14 or 45 minutes like in my examples, or even hours (and some 10 hours over several days using different filters is pretty standard procedure in astrophotography) – your stars will be nice and round and pinpoint sharp if you use a Bahtinov mask to focus (which Mirko did, but we didn’t have one the size of my small lens).
You’ll need all of that stuff, plus something more: you’ll need to be able to stand the cold, and the wind. I was really feeling cold when I got home, and that was early in the evening (short before 10pm). Imagine having to stay there for several hours more – who said that stuff would be easy?
Anyway. Now I have my scope laser-collimated, and one more interesting experience as well. Thanks again to Mirko, whom I hope to see again soon.
Thanks for reading.
P.S.: this was also a test inspired by this thread in a German astronomers’ forum, to see if my Olympus camera can do something like an Atik Infinity – and no, not out of the box. Haven’t tried it through a telescope yet, but I surely won’t get any h-alpha colours on it.