Skywatch Line for Friday, May 31, through Sunday, June 2, written by Sam Salem

This is Dudley Observatory’s Skywatch Line for Friday, May 31, through Sunday, June 2, written by Sam Salem.

On Friday, Sun rises at 5:20am and sets at 8:27pm; Moon rises at 2:03am and sets at 1:43pm.

The Moon will reach perigee, its closest point in its elliptical orbit around Earth, on Sunday, when it’s 228,727 miles away.

In the early Friday morning hours, the Moon will hang very close to Saturn. The thick waning crescent Moon will lie near golden Saturn. You can see the Moon and Saturn in dark skies before dawn.  

On the Sunday and Monday mornings, the waning crescent Moon will lie close to the reddish planet Mars. They will rise a few hours before dawn.

Mars and Saturn are up in early dawn. The highest and easiest is Saturn, in the southeast. It’s magnitude 1.2, modest, but there’s nothing else that bright anywhere near it. Its background is dim Aquarius. Look for Mars far lower left of Saturn, by roughly three fists at arm’s length. It’s magnitude 1.1, nothing else there is as bright. Mars lies in dimmer Pisces.

Constellations seem to twist around fast when they pass your zenith. Few days ago, the Big Dipper floated horizontally in late twilight an hour after sunset. Now it’s angled diagonally at that time. In just another week and a half it will be hanging straight down by its handle. The farther north you are, the quicker the Dipper seems to gyrate.

“Cassiopeia” is seen in Late fall and winter as a landmark constellation standing high overhead. In June evenings, Cassiopeia still lurks low. As twilight fades out, look for it down near the north horizon as a wide, upright W. The farther north you are the higher it’ll appear, but even as far south as San Diego and Atlanta it’s completely above the horizon.

Vega is the brightest star on the northeastern side of the sky. Arcturus is the brightest high overhead. A third of the way from Arcturus to Vega is dim Corona Borealis, the semicircular Northern Crown. Its one moderately bright star is Alpha Cor Bor, a.k.a. Gemma or Alphecca, magnitude 2.2. T Coronae Borealis, a famous recurrent nova, experiences a gradual dimming. This is a sign of being about to blow again for its first time since 1946. If it does, if could match the brightness of Alphecca. Within the next year or so, astronomers expect this event to happen. Normally T CrB simmers along uneasily at about 10th magnitude. Its explosive rise may take only about a day.

Use the finder chart to identify T CrB with a telescope.