This is Dudley Observatory’s Skywatch Line for Friday, May 8, through Sunday, May 10, written by Sam Salem.
On Friday, Sun rises at 5:40am and sets at 8:04pm, the waning gibbous Moon sets at 6:38am and rises at 9:48pm. Once the Moon is well up, look to its right or lower right for Antares, the heart of constellation Scorpius, twinkling pale orange. Around and to the upper right of Antares are lesser, whiter stars of upper Scorpius.
On Monday early hours before sunrise, look for the Moon positioned 14 degrees to the celestial west, of bright, white Jupiter. Yellowish Saturn and reddish Mars will be arrayed to the left of Jupiter. Mars, Jupiter, and Saturn shine in the southeast before and during early dawn. Jupiter, the brightest, is on the right. Before dawn begins, spot the Sagittarius Teapot to the right of it. Saturn glows pale yellow 5 degrees to Jupiter’s left. Mars is much farther to Saturn’s lower left. It’s moving away from the other two. Last Saturday morning Mars was 21 degrees from Saturn; by this Saturday it is 25 degrees away.
Venus, at magnitude –4.7, in north-central of constellation Taurus, is the bright white “Evening Star” in the west during and after dusk. It’s still shining at its brightest. Look upper right of Venus for Capella, about two fists at arm’s length away. A bit farther to Venus’s left is Betelgeuse. Much closer above Venus is Beta Tauri (El Nath), fainter at magnitude 1.6. Venus starts falling back away. Meanwhile the whole scene is sinking lower. Last Friday, Venus remained shining in the northwest for about 1½ hours after the end of twilight. By this Friday it sets only about an hour after the last trace of daylight is gone. In a telescope, Venus is growing more dramatic. This week its crescent enlarges from 39 to 44 arc-seconds in diameter, while waning in phase from 24% to just 18% sunlit. Venus is on its way down to conjunction with the Sun on June 3rd.
This weekend, the bright Moon continues to wash out fainter objects. However, you can still see some star clusters using your binoculars or telescope. Try for the Coma star cluster. It’s easy to star hop to this grouping, which is located due east of Leo the Lion’s brightest star, Regulus. Draw a line from Regulus east to magnitude 2.6 Zosma in the lion’s hindquarters, then continue along that line for about the same distance to reach the cluster.
Summer is still six weeks away, but the Summer Triangle is beginning to make its appearance in the east, one star after another. The first in view is bright Vega. It’s already visible low in the northeast as twilight fades. Next up is Deneb, lower left of Vega by two or three fists at arm’s length. Deneb takes about an hour to appear after Vega does, depending on your latitude. The third is Altair, which shows up far to their lower right by midnight.