Skywatch Line for Wednesday and Thursday, June 14 and 15, 2023

This is Dudley Observatory’s Skywatch Line for Wednesday and Thursday, June 14 and 15, written by Alan French.

The Sun rises at 5:16 A.M. on Wednesday and sets at 8:35 P.M. On Thursday it rises at 5:16 and sets at 8:35. This Thursday just under 4 ½ minutes more daylight than last Thursday. As we approach the summer solstice on June 21, the increase in the length of our days slows.

The Moon was at last quarter, having completed three-quarters of its trip around our Earth since last new Moon, this past Saturday, and is headed toward new.

On Thursday morning the Moon rises at 3:17 A,M. and will be 11 ½ degrees above the eastern horizon at 4:30 A.M. and a slender crescent, with only 8% of its visible face in sunlight. Look for earthshine, the fainter lighting of the rest of the Moon’s visible face. This is sunlight reflected from our Earth. In the Moon’s sky, our Earth would be almost full and four times the apparent size of our Moon.

If you are up at 4:30 A.M. Friday morning, a very slender, old Moon will be 6 degrees above the east northeastern horizon. Just over three percent of the Moon’s face will be in sunlight. You will need a low horizon and clear skies to spot it by eye. Thin clouds, haze, or smoke may make it hard to spot by eye and binoculars might be needed to spot it.

Venus continues to dominate the western sky after sunset, shining at magnitude -4.5. Through a telescope Venus now appears 26.8 arcseconds in diameter and we see just over 43% of its sunlit face.

The center of the Beehive star cluster is now just over one degree below Venus. The pair will nicely fit in the same binocular field of view, but the star cluster will not be at its best with its low altitude at 10:00 P.M., when the skies are finally reasonably dark. At 10:00 P.M. the Beehive will be only 14 degrees above the horizon.

By 10:52 P.M. the last vestiges of evening twilight will be gone from the evening sky. If you look high in the southwest, you will see a bright star high in the sky, just over 61 degrees above the horizon. (I find stars high in the sky seem higher than their altitudes imply.) If you are looking at the right star, you will see a kite-shaped pattern of stars stretching upward from in.

The star is Arcturus, the fourth brightest star in the night sky, and the constellation is Boötes, the Herdsman. Like many of the brighter stars, Arcturus is one of our nearer neighbors, lying only 36.7 light years away. The light you see left the star in late 1986.

Once you have found Boötes you can easily find another constellation, Corona Borealis, the Northern Crown, a small, upside down crown, just to the left of Boötes.