08/09/2016 – Ephemeris – A look at the Perseids progenitor

Ephemeris for Tuesday, August 9th.  The Sun rises at 6:38.  It’ll be up for 14 hours and 18 minutes, setting at 8:56.  The Moon, 1 day before first quarter, will set at 12:23 tomorrow morning.

Comet Swift-Tuttle is the comet responsible for the Perseid Meteor Shower which is now ramping up and will reach its peak Thursday night and Friday morning.  The comet was independently discovered by Swift and Tuttle in the summer of 1862.  Based on three months of observations it was predicted to return after 120 years in 1982. After it failed to appear more work was done to refine the orbit, and to check for past appearances of the comet.  Sure enough comets appearing to fit the orbit were found in 188 CE and 69 BCE, so a new prediction for the comet to reappear was made for 1992 by the late Dr. Brian Marsden of the Smithsonian Astrophysical Observatory.  His revised prediction was only off by 17 days.

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

Addendum

Orbit of Comet 109P/Swift-Tuttle. Blue line is the comet’s orbit, coming from above (North). Credit NASA / JPL / Applet by Osamu Ajiki (AstroArts), and further modified by Ron Baalke (JPL).

 

Orbit of Comet 109P/Swift-Tuttle. Blue line is the comet’s orbit, coming from above. That’s why the radiant is so far north.  See yesterday’s post for the radiant point. Credit NASA / JPL / Applet by Osamu Ajiki (AstroArts), and further modified by Ron Baalke (JPL).

These were generated a couple of years ago.  However the comet won’t be back until 2122 give or take.