July 25, 2009
On July 19, Jupiter was nailed again for the second time in 15 years (to the day!) by a rogue comet. This time, on the backside (ouch) as seen from Earth. Captured first by Andrew Wesley in Australia here. And by the Hubble Space Telescope here. The impactor was probably a comet, based on the high water vapor content of the black spot, and about 3 football fields across (about the same as the asteroid Apophis, which may possibly (1/5000 odds last I heard) hit Earth on Friday the 13th April 2036). The spot on Jupiter was as big as the entire Pacific Ocean at this point. A sobering sight.
On the early morning of July 25, this rapidly spreading dark disaster area rotated into optimum view for Californians. Professor Chris Kitting of Cal State East Bay and I drove up to Oak Ridge Observatory at the top of the Santa Cruz Mountains - where atmospheric stability is usually excellent - to get some video footage for stacking into hopefully great shots. I also realized this would be a good opportunity to get raw footage which could be used by my students in Astro 9 to practice this now-classic technique for planetary photography. I couldn't find my alarm clock, and set my brain to wake up after 1 sleep cycle (= 90 minutes). Well, I woke up after exactly 2 sleep cycles (brain - what is it about "1" don't you understand??), at 3:10am. I madly rushed out the door and 55 minutes later was at the outer gate to Oak Ridge - which I couldn't open and so weighted my self with gear and walked the final half mile up to the dome. Chris had his 130mm Takahashi already set up and had just finished getting all the footage he wanted. The black spot was by now rotating close to the edge, but still easily seen, and Jupiter was about 25 degrees above the western horizon. I got Cabrillo College's Canon ZR45mc camcorder mated to the Scoptronix 40mm eyepiece especially designed for the eyepiece projection technique, Chris focused the scope, I adjusted the frame exposure and optical zoom, and got off about 3 minutes of footage on the end of my miniDV tape. All Jupiter images were taken on Chris' 130mm Takahashi refractor.
Chris made this from his home on July 24, 3:30am PDT. He stacked this image from his Sony camcorder footage. Best 97 out of first 800 frames from Philips ToUcam with 7.5mm eyepiece projection, resampled at 3x, RGB stacked separately using Keith's Image Stacker. The impact scar is near the pole at upper right |
The tilt of the telescope shows Jupiter was setting low by now, and the heavy weight of my camcorder + 40mm Scoptronix eyepiece probably bent the optical path enough to cause the blue and red refraction error rims and warping of Jupiter's shape on my image. Chris' picture was taken with Jupiter higher, and with the much lighter ToUcam on the back end at prime focus. |