Spot Moon & Aldebaran

On September 30, 2018, watch the waning gibbous moon sweeping eastward through the constellation Taurus the Bull.

The bright Moon might make it tough to see all of the starlit figure of the Bull on these nights. But you should be able to make out Aldebaran, Taurus’ brightest star, as well as the tiny, misty, dipper-shaped Pleiades star cluster.

When the Moon rises in the eastern sky at about 10 pm local time on Saturday, it will be sitting less than 2 finger widths to the upper right of Aldebaran, the brightest star in Taurus. This will be their second close encounter this month.

The Moon and star will cross the sky together while the moon’s eastward orbital motion will slowly carry it just above the star. Their minimum separation of 0.5 degrees (a moon’s diameter) will occur around 2 am EDT. At that time, both objects will fit into the field of view of a backyard telescope.

Taurus is a far-northern constellation of the zodiac. That fact causes these stars to rise at an earlier hour in the Northern Hemisphere than in the Southern Hemisphere. The farther north you live, the earlier that Taurus climbs above your northwest horizon; and the farther south you live, the later that Taurus come up.

From the Northern Hemisphere, the moon and Taurus’ two major signposts – Aldebaran and the Pleiades – may well be up before your bedtime.

From temperate latitudes in the Southern Hemisphere, Taurus won’t be up until very late evening, or fairly close to the midnight hour.