AstroImages and Videos
All of the following videos and pictures were taken with my equipment at my observatory in Caledonia. The videos are the result of processing hundreds of short-exposure frames (400 for the Jupiter video). Many of the pictures were the result of processing many (sometimes as many as 120) frames at a 30 second exposure time. The exposure times were short to minimize the effects of "periodic error" introduced by the mount drive gears during tracking. I use a Nikon D50 (lense removed and attached directly to the telescope focuser, referred to as prime-focus photography, for all of my imaging. Recently I added a 2nd scope and camera to allow "guiding" by locking the 2nd camera on a star nearby the subject, and using its images (usually 1 per second) to provide corrections to reduce the periodic error. This allows much longer exposures, and fewer images to process. All control and image processing is done with special software running on an IBM R40 ThinkPad laptop computer. All frames contributing to the final result (some are thrown out because of poor quality or an airplane flying through the frame) are individually calibrated with "dark frames" and "flat frames", graded for quality, and positionally adjusted. Following those steps all are combined by a process called stacking. This allows each frame to contribute to the final result. Following stacking the "combined frame" is "digitally processed" which I can best describe as magically bringing unbelievable detail out of the final picture. Many astrophotographer amateurs spend hours (or days) performing final touchups using Adobe Photo Shop and other s/w specifically designed for that purpose. I consider myself to be a beginner at this process, but it is interesting and gratifying! CCD and CMOS imaging chips and cameras have taken much of the pain out of astrophotography - just ask anyone who used to do it with a film camera. Thank goodness for computers and equipment that allow amateurs to do things today that could only be done at professional observatories 20 years ago!!
Time-lapse video of Sagittarius
The following video was made from 170 separate images taken with a Nikon D50 DSLR using a 50mm, f1.8 lens at ASA 800. Exposure time was 15 seconds for each image, and a new image was taken approximately every 30 seconds. The total time was about 1 hr 35 min.The images were compressed and processed into an avi file using VirtualDub. The "tea pot" of Sagittarius is clearly visible in the video, as well as the dust lanes of the Milky Way. ImagesPlus software was used for camera control. A cloud bank, several aircraft and even a lightning bug (near the end) also make an appearance.
sagittarius.avi | |
File Size: | 1069 kb |
File Type: | avi |
Time lapse video of Jupiter and moons
This video was made from 400 frames of Jupiter and its 4 major moons on the night of August 13 & 14. A 1.0 sec exposure at ISO 200 was taken every 30 seconds. VideoDub s/w was used for processing into a 15fps AVI file. Total time was about 4 hours. IO passes in front of Europa (transit?) near the end of the video. The video is not long enough to show both passing behind the body of Jupiter.
jupiter-image15fps.avi | |
File Size: | 89 kb |
File Type: | avi |
The Night Jupiter's Moons Disappeared
Sept 2, 3 2009 For almost a 2 hour time period the four Galilean moons of Jupiter were invisible. At the start of the video (22:21EDT Sept 2) Callisto was already in occultation behind Jupiter. This happened before dark at my location at N43 W85. Europa & Ganymede are both together at the left side of Jupiter's disk, but separate slightly before both pass in front of Jupiter's disk and are essentially hidden (23:58 Sept 2 & 00:43 Sept 3 EDT, respectively). Io is on the right side of Jupiter in the video, and disappeared behind Jupiter at about 23:43 Sept 2. Io reappears to the left of Jupiter's disk near the end of the video (about 02:29 EDT). At 03:04 my barn blocked any further photo attempts. All four moons were hidden from 00:43 EDT until 02:29 EDT Sept 3. The AVI movie was made by combining 257, 0.5 sec exposures taken about every 60 seconds using my 8"f/4.8 Newtonian scope using tracking and guiding. The camera was an unmodified Nikon D50 at prime focus. This event will not occur again until 2019.
jupiter-moons-disappear.avi | |
File Size: | 45 kb |
File Type: | avi |