David Morrison on Comet Holmes

David Morrison on Comet Holmes

David Morrison on Comet Holmes

Bad Astronomy
The entire universe in blog form
Oct. 25 2007 11:42 AM

David Morrison on Comet Holmes

David Morrison is a NASA expert on asteroids and other objects that may one day -- if we just sit on our butts and let it happen -- send us the way of the dinosaurs. He has an informal newsletter he sends out about Near Earth Objects and related topics, and he relates some info on Comet 17/P Holmes (I'll be observing it again tonight, of course!):

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Phil Plait writes Slate’s Bad Astronomy blog and is an astronomer, public speaker, science evangelizer, and author of Death From the Skies!  


NEO News (10/25/07) Amazing Comet Holmes

This is a special note to alert you to something you may want to see, especially if you have access to a small telescope.

Approximately 36 hours ago Comet Holmes (a normally inconspicuous Jupiter-family comet with aphelion at the orbit of Jupiter and perihelion at 2.2 AU) brightened by almost a million-fold. This is equivalent to the planet Saturn suddenly becoming as bright as the full moon. On October 23-24, Comet Holmes went from magnitude 17 to magnitude 2.8 in just a few hours, doubling in brightness every half hour. At its discovery in 1892, this comet also underwent a similar sudden brightening, presumably due to a very large ejection of gas and dust.

The comet is now easily visible to the naked eye as a bright yellow "star" in the constellation Perseus. For northern hemisphere observers, it can be seen almost all night, passing nearly overhead. A good source for the latest information is the Sky & Telescope webpage http://www.skyandtelescope.com/observing/home/10775326.html or at http://www.aerith.net/comet/catalog/0017P/2007.html. The best finding chart I have seen is on the Netherlands webpage http://www.shopplaza.nl/astro/.

I looked at the comet about midnight last night from the balcony of my urban townhouse. It was about magnitude three, and at low telescopic power it was conspicuous as a bright yellowish disk, looking almost like a planet. At moderate power the disk resolved into a very bright inner coma and a slightly asymmetric fainter outer cloud, but no tail was visible. I have never before seen anything like it.

David Morrison -- +++++++++++++++++++++++++++++++++++++++++++

NEO News (now in its thirteenth year of distribution) is an informal compilation of news and opinion dealing with Near Earth Objects (NEOs) and their impacts. These opinions are the responsibility of the individual authors and do not represent the positions of NASA, the International Astronomical Union, or any other organization. To subscribe (or unsubscribe) contact dmorrison@arc.nasa.gov. For additional information, please see the website http://impact.arc.nasa.gov. If anyone wishes to copy or redistribute original material from these notes, fully or in part, please include this disclaimer.