The spectacular grouping of Venus, Mercury, and Jupiter in the evening sky after sunset will continue to delight us.
Look west at 8 tonight to see Jupiter, Venus and Mercury in a straight line, in that order, going up from the horizon. They will be quite low, and you will need an unobstructed horizon to see them in the twilight.
Try looking for them with low-power binoculars. Don't dawdle, as they rapidly set. Farther up from the western horizon will be Castor on the right (north) and Pollux on the left in Gemini the Twins.
Astronomical twilight ends tonight at 9:03. Look directly south then to see Spica in Virgo the Virgin about 47 degrees above the horizon.
Spica is the 16th-brightest star and has a distinct blue color. It is actually two stars close together that have very high temperatures of 22,400 degrees Kelvin and 18,500 degrees Kelvin, respectively, versus a temperature of 5,800 degrees Kelvin for the sun.
To the right (west) of Spica are the four bright stars that form the main portion of Corvus the Crow, and to the left (east) of Spica is Saturn. Any small telescope will show Saturn's magnificent ring system.
Nearly overhead is Arcturus in Bootes the Herdsman. Arcturus is the fourth-brightest star in the sky and has a distinct reddish orange color and a low temperature of 4,290 degrees Kelvin. Because it is so bright and fairly far north, Arcturus is the astronomer's faithful companion most nights of the year.
The moon is in a waning (growing smaller) gibbous (more than half lit) phase. It will be at last quarter Friday. A last-quarter moon rises around midnight local time and sets around noon. For example, the moon rises at 12:18 a.m. Friday morning and sets at 12:19 that afternoon.
Grand Canyon Star Party
The Grand Canyon's 23nd Annual Star Party will be held on both South and North rims from June 8-15. Park visitors will explore the night sky on the South Rim with the Tucson Amateur Astronomy Association and on the North Rim with the Saguaro Astronomy Club of Phoenix. Details at nps.gov
Contact Tim Hunter at firstname.lastname@example.org