Stars over Sisters 4/05/2022

If, after sundown this month, you were to look up in the northeastern sky, you would get a great view of Boötes, the Herdsman. Visible to observers in the Northern Hemisphere, this constellation is bordered by its celestial neighbors Canes Venatici and Coma Berenices to the west, and Corona Borealis and Serpens Caput to the east. You can easily find Boötes by first locating the Big Dipper and then extending an arc along the Dipper’s handle until reaching Arcturus, the fourth-brightest star in the entire sky (excluding our sun).

The constellation has the shape of a large kite, with Arcturus marking its bottom where a tail might be tied.

Arcturus is not only the brightest stellar beacon in this part of the sky, but it is the most luminous object north of the celestial equator. Its mass is approximately equal to that of our sun, but has a diameter that is 27 times greater. Arcturus lies at a distance of about 36.7 light-years. As of 2012, astronomers have discovered many exoplanets encircling 10 stars in Boötes.

Because Boötes is in a part of the sky facing away from the plane of the Milky Way, it does not contain any nebulae or open star clusters. The one globular cluster of note is NGC 5466, which contains a loose aggregation of stars. This cluster is unusual for its large numbers of blue stars not normally associated with globular clusters. This cluster lies 51,800 light-years from the earth.

All the other deep-sky objects in Boötes are galaxies, of which NGC 5248 is the most prominent. It is a compact intermediate spiral galaxy estimated to be about 59 million light-years away.

There are many myths regarding Boötes. One Greek legend associates Boötes with Arcas, son of Zeus and Callisto, who was the daughter of the Arcadian king. Acras was raised by his grandfather, who used him as a pawn to test Zeus by trying to sacrifice Acras to him.

The Lyrids meteor shower will peak on the night of April 21 and the early morning of April 22. Approximately 10 to 15 meteors per hour are expected to streak across the sky. The shooting stars will appear to radiate from a point in the sky near the bright star Vega.

Mercury will pop into evening sky this month, providing observers with the best chance to see the elusive planet of the entire year. The rest of the planetary action takes place in the morning sky. On the last day of April, Venus and Jupiter will appear closer together in the sky than they will be until the year 2039.

This month begins with a waxing moon, until April 16 when the Full Pink Moon arrives. From thereon the moon’s brightness will wane until the new moon shows up on April 30.

Dark-Sky Preservation

Did you know that light pollution has a negative impact on human health? Studies have shown that an increase of light pollution can disrupt the production of melatonin, altering sleep patterns. According to the American Medical Association, this can lead to increased risks of health issues.