Tuesday, September 10, 2013

Prime focus vs. eyepiece projection

Since the moon is back at a normal hour, I could do some more experiments with astrophotography. Below a comparison between prime focus and 9.7mm eyepiece projection photograph of the moon using an Meade ETX-90EC. Disappointing result for the latter, since a digital zoom on the prime focus photo is much more clear.


Saturday, September 7, 2013

Astrophotography

If you are following me on Facebook or Google+, you probably noticed that lately I have been less busy with chess programming. Instead I have been spending  free time at my Meade ETX-90EC telescope getting familiar with astrophotography.

Here are some of my first pictures using prime focus configuration (single shot manual exposure, using mirror lockup and remote control to minimize vibrations).  I really like the clarity of the moon picture and was happy seeing the ring of Saturn so clearly.


I also tried eyepiece projection configuration, but found this extremely challenging. Due to the inherent light loss at higher magnifications, it is very hard to find and focus the object (hints from experienced astrophotographers welcome!).

Today I have been experimenting with the different configurations during daytime. Below you see some sample pictures of my neighbors house number sign, taken with the camera's 300mm telelens for reference and three ETX configurations (note that the camera adapter configurations affect the picture's orientation differently). The last picture was taken at ISO-6400 to get about the same light exposure. Even during daytime, it is hard to get a good picture, which probably means I have a lot to learn. But it is a really interesting hobby!

300mm telelens
prime focus (rear port)


prime focus (adapter)
9.7mm eyepiece projection (adapter)