Bob Moler's Ephemeris Blog

Ephemeris for New Years Eve, Monday, December 31st.  The sun will rise at 8:19.  It’ll be up for 8 hours and 53 minutes, setting at 5:12.   The moon, 3 days past full, will rise at 8:51 this evening.

As we enter a new year tonight, let\s look ahead at what we expect to see in the skies in 2013.  The big events next year will be two comets that could be quite bright.  Mid-March will bring Comet PanSTARRS to the evening sky.  This is a first time comet for astronomers, so its behavior may be unpredictable, but it is currently sticking to brightness projections and may be as bright as the brightest stars at its brightest.  The second comet is Comet ISON.  This will fly close to the sun on November 28th.  It could disintegrate, its nucleus could split into multiple pieces, or it could survive intact.  The last two scenarios will give us a bright morning comet in early December.  So may we have a happy comet new year.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.

Addendum

Here are two links to the website of Seiichi Yoshida for each of the comets.  Most revealing at this point are the magnitudes graphs showing the actual brightness measurements as black dots with the predicted magnitudes as an orange line,  The vertical line is the perihelion date, the date the comet is closest to the sun.  Comet ISON has a second magnitude graph for when the comet is closest the sun and may become bright enough to be seen in the daytime.

Magnitudes are like golf scores, the lower the number the better, or in this case brighter the comet is.  the Faintest star visible to the naked eye is 6th magnitude.  Jupiter is usually around -2, Venus -4, and the sun -26.  As you can see from the scatter of the actual brightness estimates, pinning down the brightness of a fuzzy comet is rather difficult.  Comets generally appear dimmer than their magnitudes would suggest.

Here are the ;inks:

• Comet PanSTARRS
• Comet ISON