I have a new lens for my camera - a 12" Dobsonian and I am learning to take high magnification shots. Tonight I practiced on the Southern Cross and environs.
My camera is attached to the Dobsonian using a T Ring (this replaces the Camera lens and acts as a solid frame for the telescopic attachments). I then use two Barlow attachments to give me sufficient focus depth. All focusing then took place using telescope controls, which with the Canon 7D became a trial and error process.
I then turned to the sky.
Below and to the right of the bottom star in the Southern Cross - Mimosa - is a small open cluster - NGC 4755 - C94. My first couple of shots - using ISO 6400 at 25 seconds produced star trails - so I cut the exposure time to 0.5 second.
|Open Cluster NGC 4755 - C94|
The resulting photograph captures the stars and the colors - but does not do justice to the fine beauty of the cluster. The brighter stars have burnt through and even at 0.5 seconds there is still a sign of trailing or perhaps camera shake. Will have to practice more :)
I then turned to the stars making up the Southern Cross itself. Mimosa is at the top of this post.
|Gacrux - 88 Light Years M4III - Left Southern Cross|
|Eta Crux 228 Light Years K3/K4 III - Top Right Southern Cross|
|Acrux - Double Star 320 Light Years - B0.51V - Right Southern Cross|
During the shoot, the temperature dropped and the telescope began to frost over (I am about 1km high out here). I was using trigger trap and an iPhone to take the shots - I started with lots of charge but the phone drained very quickly and I had to complete with the inbuilt time delay.
1 April 2014