05/18/2023 – Ephemeris – Spica, the bluest first magnitude star
This is Bob Moler with Ephemeris for Thursday, May 18th. Today the Sun will be up for 14 hours and 55 minutes, setting at 9:07, and it will rise tomorrow at 6:10. The Moon, 1 day before new, will rise at 5:56 tomorrow morning.
In the south at 11 p.m. is the bright star Spica, which can be found from all the way back overhead to the Big Dipper. Follow the arc of the handle of the Big Dipper to the bright star Arcturus high in the southeast. Then straighten the curve of the arc to a straight spike which points to Spica, the brightest star in Virgo the virgin. Arcturus is much brighter than Spica and has an orange tint to Spica’s bluish hue. In fact, Spica is the bluest of the 21 first magnitude stars. That means that it has a really hot surface temperature. Actually, Spica is really two blue stars orbiting each other in 4 days. Spica is 250 light years away. It also was an important star to the ancient Greeks. One temple was built, and aligned to its setting point.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location.
