RocketSTEM Issue #7 - May 2014 | Page 22

Shown is a 2-inch T-2 Mount attached to Canon EOS Rebel T3i. Credit: Mike Barrett/www.wired4space.com Star trailing was mentioned above and it can be used to generate some lovely artistic effects, but generally astrophotographers want pin-sharp stars and long looked at the various types of telescopes and mounts. through the night sky allowing longer exposures without the stars trailing. However even with a telescope there is always the bright moon that can be imaged. Tracking Camera Mounts So far everything can be achieved with equipment you may already have, but to track the celestial motion you need to have an equatorial mount. This does not mean that you have to buy an expensive telescope mount though a tracking mount is a purchase you may want to make when you get a little more serious and want to start taking longer exposures. There are a number of systems on the market: Astrotrac, Vixen Polarie, and the iOptron SkyTracker are three popular ones. They all work on the same basic principal: the mount is aligned with the celestial pole (close to Polaris 20 20 in the northern hemisphere) then the camera mount is rotated at the same rate as the stars revolve around the pole. All of these mounts are light, small and very transportable, but require the addition of a tripod, and some kind of tripod head. With the addition of a simple programmable timer this makes for an excellent portable astrophotography system. The exposure can easily be increased from 30 seconds to 3 minutes even with a 200mm telephoto lens. With this type of setup you will be able to do some deep space photography and if you are anything like me you will get the bug and want to improve your skills and take your photography to another level. Conclusion As can be seen astrophotography does not have to involve huge expenditures and a lot can be done with equipment that you may already own or have access to. Obviously this is just an introduction to help you get started, and there are so many more levels to the subject. I will be covering some these in future articles, including planetary imaging which can done very easily using webcam. www.RocketSTEM .org