Starting the year with a comet
Published on Jan 1, 2008 at 5:45 pm.
4 Comments.
Filed under comets.
2007 was a year for spectacular comets. First there was Comet McNaught (C/2006 P1) in January. I almost missed that one, as I was in Seattle at an American Astronomical Society meeting. Then, a couple months ago, we had Comet Holmes (P/17 Holmes). Both comets were visible to the naked eye even from light polluted city skies. It is rare for a comet to get that bright, and to have two in one year is really unusual. Comet McNaught was on its first trip past the Sun. Comet Holmes has been known for a century, but since its discovery it has been a very faint and unimpressive object. It had a sudden outburst in October, when it brightened by nearly a factor of one million.
Now, we have Comet Tuttle (8/P Tuttle). (Thanks to Tom for posting something about the comet that gave me the idea to post something myself.)Â Like Comet Holmes, Comet Tuttle has been flying around the inner Solar System for some time. The famous astronomer Horace P. Tuttle discovered the comet in January of 1858. Several observations of the comet allowed him to compute its orbit, showing that it was almost certainly the same comet discovered by Pierre Mechain (one of Charles Messier’s colleagues) in January of 1790. Note that the comet is not seen every January. It orbits the Sun with a period of about 13.6 years. The orbit is inclined almost 55 with respect to the ecliptic. So, the comet approaches near Earth’s orbit at about the place that the Earth is located in January. But, you only get a good view of the comet when both the comet and Earth are in approximately these spots at nearly the same time. That is happening now. In fact, tomorrow, Comet Tuttle will be the closest to us, at about 0.25 Astronomical Units. That is actually quite close for a comet. However, this comet has been passing through the inner Solar System for a long time, so it has lost much of its volatile materials. That means that it isn’t very bright. However, it is passing quite close to us, so it appears a bit brighter than normal. In fact, it is right at the threshold of naked eye visibility. However, don’t try to see it from light polluted skies. To have any hope of seeing it with the naked eye, you need to get out into dark skies.
The comet is already putting on a show, and numerous photographs have been submitted to Spaceweather’s comet gallery. But, the comet is still rather dim to see with the naked eye. In fact, you need to have very dark and clear skies to have any hope of seeing it with the naked eye. But, it should be quite nice in binoculars. The only trick is to look in the right place. We are fairly close to the comet, but Earth and the comet are moving in much different directions through space. That means that the comet is moving through the sky very quickly. In this case, quickly means several degrees per day, not quickly enough to see it moving with the naked eye! I have produced a finder chart below for tonight using Stellarium (and manually inserting the comet using Paint).
Right now, the comet is nearly overhead for observers in the mid northern latitudes. It is rapidly moving south, and so it should be a southern hemisphere object in a few weeks. Because it moves so much, you need to know where to look. An ephemeris is available. But, you can also go to the Spaceweather.com web site and create a finder chart for the comet for the night that you wish to look for it.
It is interesting to have yet another comet in a string of comets. Only three years ago, Comet Machholz (C/2004 Q2) also reached naked eye visibility. I don’t really recall so many over such a short period of time. In ancient times, comets were often regarded as harbingers of doom. Thankfully, I don’t subscribe to that idea, or else I’d be getting pretty worried!
-Astroprof
Brian W. on January 2, 2008 at 2:34 am: 1
could you possibly have inverted the star chart?
Ed Davies on January 2, 2008 at 6:21 am: 2
I don’t think the chart is inverted as such. It looks like it has celestial north up (i.e., it’s aligned with equatorial coordinates) so it would look inverted to a southern hemisphere observer but just somewhat rotated to a mid-latitude northern hemisphere observer looking later than about 19:00 local time in the evening - the time when the comet is in the south.
Astroprof on January 2, 2008 at 11:15 am: 3
Yes, the chart is made for about 19:40 or so, facing south. Straight up is near the middle of the chart.
Another comet, plus M33 « Stars on January 2, 2008 at 6:30 pm: 4
[…] I spent some time on the front steps looking in the direction of Triangulum with my binoculars, specifically trying to locate the 8P/Tuttle comet. Well, my position for Tuttle was based on a day old map, and this comet is moving very quickly. After 10 minutes in 20° weather searching, I actually found M33. M33 had eluded me for months. It looks like an faint oval cloud. [note: I need new language to describe “faint” things if I expect to have any luck remembering details about these “faint fuzzy” objects] […]