I can set the exposure time for 1100D to max 30s. While this is a long time, it's not enough for photographing nebulae or other dim objects. I got a tracking mount EQ3-2 which is supposed to make possible exposure times of couple of minutes. Still I have to take several exposures of the same object to get total exposures of maybe 20 minutes. I still haven't had a chance to test my equipment because of the summer here in Finland. Too much light even on midnight.
To take exposures longer than 30s I have to use camera's bulb setting. I use mainly Linux at home so I can't use Canon's EOS utility. Luckily there is Gphoto. It doesn't support all the cameras and for a while looked like 1100D wasn't on the supported list. I could take photos and change settings but couldn't get bulb to work. Developers on #gphoto in Freenode were kind to help me out and the correct commands for changing settings and using bulb are:
# gphoto2 --set-config iso=400
# gphoto2 --set-config shutterspeed=bulb
# gphoto2 --wait-event=2s --set-config eosremoterelease=Immediate --wait-event=180s --set-config eosremoterelease=Off --wait-event-and-download=5s
The red --wait-event tells camera the exposure time in seconds.
I'll probably get the adapters required to mount camera on EQ3-2 next week and be able to test everything. Later I'm supposed to get a Raspberry Pi (might take two more months) and my plan is to use that to remote control the camera. I'll install Debian on the RasPi and use ssh to control it. If everything works as planned I'll get to sit inside while taking the photos of night sky.
If I blog here about instructions for something I usually write about it to a website as well. Blog doesn't work too well with information that might change and the reason for me to blog is to help others that might be doing the same thing. So you might want to check this page for Gphoto instructions.
- Using Gphoto2 to control EOS 1100D on my website.