The Astrotrac portable tracking mount has created a substantial buzz among people interested in astrophotography lately. It’s easy to set up, “easy” to polar align, and should track very accurately for such a small mount. I use it on a manfrotto 410 geared head and I mount my Canon 40D dslr on a Benro ball head on top of that. I have a Canon 70-200 f4 L lens that seem to do the job nicely for astro work.
The assembling of the tripod, mount and camera is really easy, and takes five minutes to do. Because of it’s light weight I did it indoors, and moved the whole thing out when I was ready to start imaging. The polar scope fits in a movable arm and has nice illuminated markings indicating where Polaris and other stars should be when the setup is properly aligned with the earth’s axis. This is a crucial step to get right to get good results. It was my first time using a polar scope, and it was quite difficult to focus on the stars to put them in the annotated areas. However, after about ten minutes I was fairly satisfied. Let the imaging begin!
I planned to start with an easy target, m31 - the Andromeda galaxy, and then see if I could capture the reflection nebula around the stars in the m45 Pleiades open cluster. However, it soon turned out that the dew point would be a problem this night. Dew formed on the lens almost immediately, and I had to use a hair dryer to remove it between each or every second exposure. A lot of subs were lost because of this, but the result I got was nevertheless better than any I have done previously since this is my first proper tracking mount. Here are some of the evenings results:
All stacks of five subs and one dark.
All in all I’m very happy with the astrotrac, and I think the mission is accomplished for the first light goals! See the full size images on my flickr account.
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