Ursid meteors, Mars in Reverse, the Moon and Pleiades

Here’s a little Holiday treat you might want to stay up late (or get up early) for. The Ursid meteor shower peaks on the morning of Tuesday, 22 December. As you may have guessed by the name, the Ursid shower’s radiant is circumpolar, near Kochab, the “front” star in the bowl of Ursa Minor, the little dipper. Ursids are the dusty debris of comet 8P/Tuttle and tend to be faint and relatively slow moving.

The American Meteor Society offers these Ursid observing tips:

Most of the Ursid meteors are faint therefore it is important to observe from rural areas away from city lights. Since the radiant lies in the northern half of the sky it would be best to face this general direction to see the most activity. There is no need to stare directly at the radiant, rather it is advised simply to place the radiant somewhere within your field of view so that it will to easy to trace which meteors line up with Kochab (Ursids) and those that don’t (non-Ursids or sporadics). From dark skies one should also be able to count 10-15 sporadic (random) meteors per hour.

Mars in Reverse

I don’t think you’ll hear a backup warning beeper but Mars began retrograde or apparent westward motion on 21 December. What this means in practical, observable, terms is that as Earth overtakes Mars as we approach opposition in late January the Red Planet will appear to move westward against background stars. Mars will retrograde more than 10 degrees from western Leo into central Cancer during January, 2010. You might consider observing Mars at least once a week for the next month. I suggest you use the star Regulus, Leo’s “front paw” as a reference point. Measure the angular separation between Mars and Regulus by fully extending your arm and using your fist as a reference. Remember when your arm is fully extended your fist subtends 10 degrees, an open palm with outstretched fingers about 20 degrees. I’ll venture a guess that as I write this Mars is about 13 or 14 degrees west of Regulus, or “a fist and a couple of fingers”. If you’d like to know more about using using fingers, hands and fists to measure angular distances in the sky contact me here.

Mr. Moon and the Seven Sisters

The Moon will glide by the Pleiades on the evening of Tuesday, 29 December. You can observe this one naked eye but the Moon will be two days away from full and very bright. Binoculars will show a very nice view of the Moon less than a degree west (to the right) of the Seven Sisters.

Finally I should mention what will likely be the last celestial event of note during 2009 and the IYA. There will be a penumbral lunar eclipse on 31 December which will be visible in the Eastern Hemisphere. If it happens to be dark where you are at 19:23 UT (2:23 pm EST) on New Year’s Eve you’ll have to look carefully for this one. The umbral magnitude of this eclipse will be 0.082. In other words only a very tiny fraction of the Moon’s disc will fall under the Earth’s shadow.

Skies have been overcast here in southern Indiana for over a week so we’ve missed the Geminids, Mercury and the Ursids. Hope your New Year will be great and your Skies Clear!