Monday, September 9, 2013

Test run on Raspberry controlled camera (and some nice photos)

I never got around to testing the camera controlling script I wrote on Raspberry Pi before now. I don't remember the internals of the script but luckily I made it extremely easy. I had Raspbian on a SD-card, I installed Gphoto2 and Gcc (required to compile usbreset) and took Raspi on balcony with EQ3-2 and camera.

It took me a while to set up networking (cable out of window) so I could control Raspi remotely but when I had it all set up, everything worked perfectly. I turned the camera to face brightest star I saw (Altair), focused the camera and took some test photos. Here's a single shot with 200 mm focal length, 30 s exposure time and ISO1600. Quite good considering I'm taking these in a city not long after sunset.


Sky was clear. All the crappiness from my camera.

Benefits of Raspi system

I can't take too long exposures. With 200 mm focal length it seems 25-30 seconds is maximum. EOS 1100D can do that. Why this Raspi setup is nice then?
  • More than 10 shots at a time. With just the camera I can take 10 at a time, then have to go and press the trigger once more. This is surprisingly annoying.
  • Automatic upload to NAS. I sat at my computer and watched new photos flow in. With just the camera I have to look at test photos from its screen. Now I saw them instantly on a good screen and following adjustments were a lot easier to do.
  • Automatic naming of photos. I have way too many photos named IMG_4244.CR2 and such. I organize them according to date and object but when unloading the camera I have to remember everything I tried to capture.
I'm considering of building some kind of system for Raspi to control EQ3-2's motor. Last night I had to get up, go out and turn the camera a bit. Come back inside and check results. Then the same again for n times. I've been told the motor on EQ3-2 is way too slow for this so perhaps I'll think some other solution... Anyways, to business:

The test photos

From a star chart I saw that M11, Wild duck cluster, should be nearby my "calibration" star Altair. It was quite easy to locate the cluster and after couple of test photos I got it centered. Later on I noticed M26 is just a bit down and turned the camera there. It fit easily on same photo. Here's some results:

Whole view with M11, M26, NGC 6712 and NGC 6704
Last time I tried to upload a photo this size, Google automatically resized it so here's the original on Flickr if that happens. I also put this on Astrobin.

Nova.astrometry.net is a nice service of astrometric plate solving. The software is free, but I still haven't got around to installing it. It wasn't trivial. Meanwhile this service works. Astrobin also does the plate solving but for some reason it doesn't show me the annotations on full resolution image. That would be nice. Anyways, I got this from nova.astrometry.net:
Source of annotated image: http://nova.astrometry.net/user_images/75597#annotated
Quite a lot in one photo. Some of those I cut in their own pictures:

M11 - Wild duck cluster

M26

NGC 6712

NGC 6704.... I quess.
Move along. Nothing to see here.