Bob Moler's Ephemeris Blog

Ephemeris for Independence Day, Monday, July 4th.  Today the Sun will be up for 15 hours and 27 minutes, setting at 9:31, and it will rise tomorrow at 6:03.  The Moon is new today, and won’t be visible.

There are two astronomical highlights for your Independence Day enjoyment.  The first comes at 11:59 this morning (15:59 UT) when the Earth is at its very farthest from the Sun this year.  Some 1.7% farther than average.  You’re still gonna need your sun screen anyway.  Later this evening, a half billion miles from Earth NASA’s Juno spacecraft will fire it’s rocket engine for 35 minutes to begin to decelerate over the north pole of Jupiter to drop into a long elliptical orbit of that planet.  NASA TV will begin broadcasting the event at 10:30 p.m.  (2:30 UT, July 5) The 35 minute engine burn will start at 11:18 p.m. (3:18 UT, July 5)  What we’ll see is a real-time graph of the Doppler signal from the spacecraft as it slows down to drop into orbit of Jupiter.

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

Addendum

The Juno spacecraft. Credit: NASA.

The Planetary Society’s Emily Lakdawalla has more information on How to watch Juno’s orbit insertion at http://www.planetary.org/blogs/emily-lakdawalla/2016/07011514-how-to-watch-junos-orbit.html.

NASA also has an application in which you can see simulations of Juno’s orbital insertion.  It’s called NASA’s Eyes and can be downloaded from http://eyes.nasa.gov/.