Mars 11/14/09 6:00am

16 November 2009

Here in Seattle we have had about four weeks of uninterrupted clouds. Last Saturday morning the Clear Sky Chart predicted clear skies around 4am PST – a perfect opportunity to image Mars.

Friday night I set up the scope, and Saturday morning at 3:50am I woke up to the sound of my alarm clock. Nice clear skies outside. I started setting up the scope and doing the collimation of the mirrors. Collimation is an important detail – especially for imaging planets. It needs to be dead-on or your images will turn out distorted. You do this by focusing the telescope on a single star in a section of sky near the planet you want to image. You then adjust the orientation of the secondary mirror on the telescope to cause the “airy disk” to appear perfectly concentric. I just about had collimation done and it clouded up again. Shoot!

I ended up doing work email for about an hour and a half while I waited for a clearing. I really wasn’t expecting it to clear, what with the rainy weather lately. I wasn’t ready to give up yet either, so I decided to hang out and see what the weather did. Luckily, around 5:45 PST the sky managed to clear up. Now with only 20 minutes before sunrise, I had a decision to make: Do I do finer collimation or do I shoot video? I decided to bag the detailed collimation and shoot the video.

What you see here is actually my first Mars photo. I’ve photographed Jupiter before, but never Mars. Note that the white area at the top of Mars is the polar ice cap.

Here are the image stats:

Scope: Celestron 9.25″ Schmidt-Cassegrain
Camera: Imaging Source DMK21AU04
Optics: Celestron 3x barlow, Astronomik type 2C R,B filters
3500 frames R 1/30 second exposure at 30fps, 1000 frames B 1/5 second exposure at 7.5 fps
RsGB technique

Image taken at 6am PST from Seattle, Washington USA

mars_091114_rgb2_3

I used the “synthetic green” technique as described by Damien Peach in this article: http://www.damianpeach.com/marscolour.htm

Note that Mars was only around 8 arc seconds across (apparent diameter) at the time this photo was taken. To compare, the photos of Jupiter that I took earlier were around 45 arc seconds in apparent diameter. On the plus side, Mars is about 61 degrees above the horizon vs 25 degrees for Jupiter. A higher altitude in the sky means less atmosphere to look through, and the result is a clearer image.