The coma is about 7.5 arc min across and background stars can be seen through it. These two images were taken with the 32-inch on Monday, October 29, 2007 (CDT) using V and I filters. Each image is 10-seconds (no stacking).
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Comet Holmes, 20071030 0:44 UT, 10 seconds at f/4.5, 32-in Newtonian, V filter, 820×700 cropped from original 1024×1024 frame, Digital Development in MaximDL
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| Comet Holmes, 20071030 0:47 UT, 10 seconds at f/4.5, 32-in Newtonian, I filter, 820×700 cropped from original 1024×1024 frame, Digital Development in MaximDL |
Comet Holmes continues to astound astronomers around the world. The coma is almost 7 arc min across and background stars can be seen through it, causing many to speculate that the comet nucleus has split. That doesn’t seem to be the case at this writing. The stars can be found in catalogs such at the GSC. These two images were taken with the 32-inch on Sunday, October 28, 2007 (CDT) using V and I filters. Each image is 10-seconds (no stacking).
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| Comet Holmes, 20071029 01:44 UT, 10 seconds at f/4.5, 32-in Newtonian, V filter, 820×700 cropped from original 1024×1024 frame, log stretch in MaximDL |
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| Comet Holmes, 20071029 01:44 UT, 10 seconds at f/4.5, 32-in Newtonian, I filter, 820×700 cropped from original 1024×1024 frame, log stretch in MaximDL |
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Comet 47P/Holmes made a surprise entrance to our skies over the last 48 hours or so. Normally at magnitude 17, it suddenly jumped to magnitude 3 or so - easily visible to the naked eye under full moon conditions in Perseus. That’s an increase in brightness of nearly 400,000! At this writing, the best guess as to what happened is that the nucleus split into many pieces or a particularly rich vein of ice became exposed. In the 32-in the comet showed a coma of almost 1 arcmin diameter with a bright nucleus. No tail was evident (the Moon was almost full, though) and the color was a definite pale yellow. I imaged the comet with my 10-inch LX-200 through a V filter at 940 mm efl and ST-7 camera. The image below is the result of stacking 10 0.11 sec exposures, then doing a log histogram adjustment on the image. It fairly recreates the view seen in the telescope.
Cartes du Ciel planetarium software can import orbit parameters for comets (among other things) such that their positions can be shown against the starry background. The motion of the comet can also be animated to display graphically how the object moves across the sky. I imported the currently visible comets parameters from the Minor Planet Center and made the following animation. The animation starts at 11:00 pm CDT July 9, 2007 with Comet C/2006 VZ13 (Linear) in Draco (it’s the little symbol that looks like a letter "d") and proceeds one day at a time at a one second per frame rate. Note that on July 22, 2007 the comet passes close to M3.
The 10.5 magnitude asteroid 372 Palma passed directly in front of the magnitude 6.2 star 32 Lyncis as viewed from a broad swath that reached all across the the U.S., but more particularly across the northern regions of Missouri. Scientific value can be gained by observing such an occultation and timing precisely when it begins and ends. By combining observations from many observers scattered across and along the path of the shadow, the orbit of the asteroid can be refined and an estimate of the size and shape of the asteroid can be made. In this particular case, the event was predicted to occur about 09:45 UT on January 26, 2007 (3:35 am CST).
Wayne and Nancy Clark, Yvonne and I traveled north from Wentzville, Missouri to LaGrange, Missouri where we observed the event and got timings. Our geographical location was 40 02.679 N and 91 30.124 W and 611 ft elevation as determined by two different GPS receivers. It was 22 deg F. at the time of the observations. The occultation lasted just over 13 seconds beginning at 09:45:5.04 and ending at 09:45:18.27 as determined by measuring audio signals against a background of WWV time signals.
