Underappreciated, the blue sky is caused by the preferential
scattering of short light waves in the solar spectrum.
Astronomy news for the two weeks starting Friday, May 5, 2017.
The next Skylights will appear Friday, May 19.
The fortnight belongs to the Moon; it's the "bright
run" in astrospeak.
We begin with the Moon in its late waxing gibbous phase, full Moon taking place on Wednesday, May 10.
The Moon passes 2 degrees north of Jupiter, Sunday, May
7; Spica is to the south.
After the waning gibbous phase , The Moon hits third
quarter on Wednesday, May 18, shortly before Moonrise in North
The Moon passes 3 degrees north of Saturn, Saturday,
The Moon goes through apogee, farthest from Earth, on
Friday, May 12, shortly after the full Moon.
Planets and the Solar System
Mercury is at
greatest elongation west of the Sun, 26 degrees, on Wednesday,
May 17. It presents a poor sight as the planet rises in bright
Jupiter, dominating the nighttime sky, crosses the meridian around 11 PM, just as Saturn
Venus, much brighter than Jupiter, rises at dawn,
around 4 AM, about as Saturn transits the meridian.
In the early evening, Perseus, northeast of Andromeda and northwest of Auriga, descends the northwestern sky. The dense
central part of Perseus is a cluster buried in a much larger unbound association of hot
stars. Auriga features Capella, the most northerly first
magnitude star, just slightly farther north than Deneb in Cygnus, which is at the northeast apex of the Summer Triangle. The most
southerly star is Acrux in the
Southern Cross, which is
perpetually below the horizon for almost all the US. In mid
evening Leo and its bright star
Regulus crosses the meridian.
Southwest of Regulus is the lonely star Alphard, the luminary of Hydra, the Water Serpent, the
longest constellation of the sky.