Archive for December 19, 2019

12/19/2019 – Ephemeris – What does the bright star Procyon’s name mean?

December 19, 2019 Comments off

Ephemeris for Thursday, December 19th. Today the Sun will be up for 8 hours and 48 minutes, setting at 5:04, and it will rise tomorrow at 8:16. The Moon, at last quarter today, will rise at 1:42 tomorrow morning.

Visible low in the east at 8:30 p.m. will appear the star Procyon, sometimes called the little Dog Star. It’s in the constellation of Canis Minor, the little dog. It will rise at 8:05 p.m. for the Traverse City Interlochen area. Yet to rise at that time is the Dog Star itself, Sirius, the brightest night-time star. It won’t rise until 8:40 p.m., 35 minutes later even though Sirius is west of Procyon. I bring this up because the name Procyon means Before the Dog. At our latitude Procyon rises before any part of Canis Major, the big dog, Canis Major, that Sirius is in the heart of. This is sensitive to one’s latitude. At the equator, say in Ecuador. Sirius would rise first due to its westerly position by 54 minutes. You see Procyon is also north of Sirius and that makes all the difference.

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


Procyon rising before Sirius

Stars and constellations in the east at 9 p.m., about 4 hours after sunset, on December 19th. This only works for locations above 30 degrees north latitude. Created using Stellarium.

Procyon and Sirius will for observers located at 30º 30′ north latitude.  South of that latitude Sirius will rise first.