Thinking About a New Scope? Think Big!
Straight Forward Prime Focus
Jupiter grazing occultation - Nov. 2, 2012
Talking about having fun – the 18 inch Obsession + Canon DSLR (7D and 5D) – no stacking etc. – just straight forward prime focus (bottom part of a barlow lens - attached to camera adaptor/ nose piece).
We were fortunate to see a grazing occultation and the photon shields (clouds) stayed away JUST long enough!!
Pretoria, South Africa
CCD and video astrophotography
The Horsehead Nebula, B33 - photogpaphed by Glenn Schaeffer using 20" Obsession. Visit his website
Imaging with a large aperture reflector like the Obsession is exciting. The large light gathering area means CCD exposure times are very short - usually under a minute. Minimal guiding or none at all. Multiple images are stacked in your PC to build up a vivid image. With proper software, field rotation at the focuser is elliminated.
Live video work is the ultimate in immediate gratification. The newer cameras are very sensitive. Entertain a crowd with deep sky images on the monitor. Actually see deeper than you can with eye at the eyepiece in real time! Or connect to a DVD camcorder or VCR and capture the video to watch later. Or make stills of the best shots.
To learn more about imaging with an Obsession, please see the work of these Obsession owners:
Johannes Brachtendorf photos
Todd Kozikowski photos
Becky Coretti photos
Occultation of Jupiter taken by Becky Correti and Bill Williams with web cam and 15" Obsession. This photo series also appears in the April 2005 issue of Sky and Telescope on page 132. Visit Becky's website
Doug Murphy photos
Hi Dave, Long time, no write! Clearly, I’ve been having a good time with my 18UC. As you saw from the post I do a lot of video-astro imaging with MallinCam from the back yard, but the video provides a live feel to observing that guests and visitors get excited about, and the views with extreme light pollution in suburban DC are like views you can get in a 50 inch under dark skies. And then again there’s the color. It's a great way to go. Feel free to use these photos. Emphasize that they are just video frames. They match very closely what you can see live looking at the color monitor next to the scope. Here are the conditions:
- 18UC with Mallincam HP color video camera
- Mirror is moved out, but poles not shortened (yet)
- MFR3 focal reducer and extenders gives f/2.7 effective focal ratio
- Camera integration generally set at 14 sec, sometimes 28 sec, only 1-2 steps of gain, gamma = 1
- SVHS output to a Matrox MXO2mini frame grabber
- Frame grabbing rate set to match integration time of the camera and controlled by iStopMotion (Boinx Software) on a MacBook Pro laptop
- Pictures are the averages of about 4 frames in Lynkeos software on a Mac
- Adjusted contrast and gamma and color balance in Photoshop
So you see, I’ve been lovin my 18UC and having a wonderful time with the stars. My mirror is a beauty. These are recent photos of the March skies.
Doug Murphy, Leesburg, Virginia