Bob’s Ephemeris Blog

Asteroid 2007 TU24 will miss the earth by 1.3 times the distance of the moon later this month.  Phil Plait at Bad Astronomy has the low lights of a crackpot theory that will have this tiny asteroid will decimate the earth.  And, oh yes that Comet Holmes is more massive than the sun.  Phil links to the video.  The picture of the asteroid in the video, which we have no image of, looks a lot like the asteroid Ida. I won’t touch the video with a 10 foot patch cable.  Check it out here if you dare.

Tags: Really dumb by Bob Moler
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The planet Mercury will get its first visitor from earth in almost 33 years on Monday, January 14, 2008. The MESSENGER spacecraft will make its first pass of Mercury, giving some of its energy to the planet to adjust its orbit, so that on its planned 4th encounter with Mercury in 2011 it will be able to drop into orbit of this tiny planet. MESSENGER is named for the mythology that Mercury was the messenger of the gods, named in honor of the planet’s fleeting motion. However MESSENGER is really a rather tortured acronym: MErcury Surface, Space ENvironment, GEochemistry, and Ranging. The time of closest approach to Mercury will be at 2:05 p.m. on its night side. It will get a look at part of it’s known side on the way in, and a peak at unexplored territory on the way out. More information and an animation of the planned flyby is here. The Planetary Society has more information and approach pictures of Mercury here. The official MESSENGER web site is here.

If you want to know more about the Mariner 10 Mission to Mercury in the mid 1970’s including photographs click here.

Photographs, according to the Planetary Society’s blogger Emily Lakdawalla won’t be received until the 16th, and there doesn’t seem to be a policy of putting raw images on the mission web site like JPL (Jet Propulsion laboratory) does with Cassini and the Mars rover missions. This mission is being run by Johns Hopkins University’s Applied Physics Laboratory.

Tags: Events, Planetary Space Missions by Bob Moler
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On the morning of January 4th we will see the peak of the Quadrantid Meteor Shower.  The actual peak will be about 1:40 a.m. EST,  That’s 6:40 UT.  The hourly rate when the radiant of the shower is overhead can be anywhere from 60 to 120. This active meteor shower has its radiant north of the kite shape of Boötes and near the handle of the Big Dipper. The moon’s illumination will be18% and it will rise at 5:16 a.m., so it will be out of the way until just before morning twilight starts  Meteor showers are named from the area of the sky they seem to come from. The quadrantids appear to come from the obsolete constellation of the quadrant that’s now part of Boötes the herdsman.

Above is a chart of the radiant at 1:40 a.m. from Traverse City.  We are looking northeast near the horizon.  The radiant is marked QuadR

Tags: Events, Observing by Bob Moler
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About 7 this evening (January 2nd) the earth reached perihelion. It’s a big word that means the closest point in the earth’s orbit of the sun. Today the sun will be 91.4 million miles away. The sun’s disk will be the largest of the year, of 32.5 minutes of arc. A bit more than half an angular degree. At the sun’s farthest, July 5th it’s 30.9 minutes of arc. So the earth really doesn’t change distance from the sun much. The earth or anything in orbit moves fastest when closest to their primary. That means winter is the shortest season of just under 90 days, though that fact is somewhat obscured by our location in northern Michigan, where snow starts as early as November, and can hang on until May, so it kind of feels like the reverse is true. It may seem like winter stretches out before us but cheer up, Ground Hog Day is only a month away.

Tags: Events by Bob Moler
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This is a bit late, but have a Happy New Year. It’s a year with 366 days, most of which are campaign days for the elections, presidential and otherwise. I’ll try to keep above the fray by checking what’s up in the sky and beyond the earth.

On January 14th the MESSENGER spacecraft will fly past Mercury for our first close look at that planet in nearly 33 years. The spacecraft has several more passes of Mercury before settling down in orbit of it in 2011.

February 20th will see the third and last of a series of total lunar eclipses that were and will be visible from around here. The previous two were clouded out last year, at least for me. Let’s hope the third one is the charm.

Easter for western churches will be extremely early this year at March 23rd, the earliest since 1913 which tied it. We have to go all the way back to 1818 to have Easter occur earlier, on March 22nd.

Tags: Events by Bob Moler
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