2021, August 30: Last Quarter Moon, Hyades


August 30, 2021:  The morning moon is near Aldebaran and the Hyades star cluster.

Chart caption – 2021, August 30: Through a binocular the morning moon is 5.4° to the upper left of Aldebaran and the Hyades star cluster.

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by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 6:15 a.m. CDT; Sunset, 7:27 p.m. CDT.  Check local sources for sunrise and sunset times for your location.

Before sunrise, this morning the Last Quarter moon is high in the southeastern sky.  It is near the star Aldebaran and the Hyades star cluster. Together the bright star and the star cluster make the “V” of Taurus.  It represents the head and eye of the Bull.

The lunar orb is 5.4° to the upper left of Aldebaran – “the follower.  The star is silhouetted against the Hyades star cluster.

Use a binocular to locate the moon and move it so that Aldebaran and the star cluster are in the field of view together.  Once the three are in the field, move the binocular so that the moon is outside the view.  This reduces the glare caused by the moon and makes the stars easier to see.

Unlike the Pleiades star cluster, the Hyades has several yellow and orange stars, along with blue-white stars, indicating that on an astronomical scale the Hyades are older than the bluer Pleiades.

Aldebaran is known as a red giant, The yellow orange star is about 65 light years away.  It shines with the intensity of 125 suns.  It has a diameter of about 40 suns.

The Hyades cluster, like all the stars, is revolving around the galactic center.  The stellar bunch is moving toward the region of Betelgeuse.

The cluster’s distance (150 light years) and movement were instrumental in determining the properties of stars and distance.  Using stellar brightness as a “candle” can help determine distances when the brightness of stars is compared.  Determining the actual brightness of standard candles, whether they are stars or distant galaxies, was a challenge and scientific battleground to determine the size of the galaxy and the universe.

In the evening sky, look westward for Venus after sunset, while bright Jupiter and Saturn are in the southeastern sky.

Detailed Daily Note:The moon is at its Last Quarter phase at 2:13 a.m. CDT.  One hour before sunrise, the moon (21.8d, 49%) is over two-thirds of the way up in the southeast, to the left of a line from the Pleiades to Aldebaran. The lunar orb is 9.5° to the lower left of Alcyone and 5.4° to the upper left of Aldebaran.  Use a binocular to place the moon and the “V” portion of the Hyades star cluster in the same field of view. Note the varying colors of the stars in the cluster and that Aldebaran is not part of that stellar family. Twenty-five minutes after sunset, Mercury is over 4° up in the west, 16.2° to the lower right of Venus.  Use a binocular. Fifteen minutes later, brilliant Venus is nearly 8° up in the west-southwest, 6.7° to the lower right of Spica.  Farther eastward, Saturn is over 18° up in the southeast, 17.6° to the upper right of bright Jupiter. Jupiter is over 12° up in the southeast.  Two hours after sunset, bright Jupiter is over 20° up in the southeast, 3.3° to the upper right of ι Aqr, 0.6° to the lower right of μ Cap, and 2.4° to the upper left of Deneb Algedi.  Saturn is nearly 26° above the south-southeast horizon, 1.0° to the lower left of υ Cap.


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