Moon, Aldebaran, Pleiades before bedtime

On September 19 and 20, 2019, watch as the waning gibbous moon makes an appearance in front of the constellation Taurus the Bull. The bright moon may make it tough to see 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.

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 northeast horizon; and the farther south you live, the later that Taurus comes up.

If you’re not one to stay up late, get up before daybreak to view the moon and Taurus higher up in the predawn sky.

From the Northern Hemisphere, the moon and Taurus’ two major signposts – Aldebaran and the Pleaides – 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.

Click here and check the moonrise and moonset box to find out when the moon rises into your sky.

Click here and check Aldebaran as your celestial object of interest to find out when Aldebaran rises into your sky.

The ecliptic - the sun's yearly path through the constellations of the zodiac - passes through the constellation Taurus the Bull, to the north of the star Aldebaran and to the south of the Pleiades star cluster. The sun shines in front of Taurus from about May 14 to June 21.

The ecliptic – the sun’s yearly path through the constellations of the Zodiac – passes through the constellation Taurus the Bull, to the north of the star Aldebaran and to the south of the Pleiades star cluster. The sun shines in front of Taurus from about May 14 to June 21, every year.

When the moon travels in front of Taurus (or any constellation of the zodiac, for that matter), the moon can travel anywhere from 5 degrees north to 5 degrees south of the ecliptic. For the next several years, the moon will remain south of the ecliptic in its monthly travels in front of Taurus the Bull.

A little over a year ago – on September 3, 2018, – he moon occulted (passed in front of) Aldebaran, presenting the final occultation of a monthly occultation series that started on January 29, 2015. But month by month, and year by year, the moon’s trajectory will slowly but surely shift northward as it goes through Taurus the Bull. In fact, for the next 15 years, the moon will be sweeping to the north of Aldebaran and to the south of Alcyone, Pleiades’ brightest star.

The monthly occultation series involving the moon and the Pleiades star Alcyone will take place from September 5, 2023, till July 7, 2029.

When the moon moves away, try this. The 3 stars of Orion’s Belt always point to the star Aldebaran and the Pleiades star cluster. Image via Janne/Flickr.

The Skidi Pawnee in the American Great Plains (Nebraska) used the Pleiades cluster as a calendar marker. When they saw the Pleiades cluster through the smoke holes of their lodges just before dawn, they knew it was time to harvest the crops.

Before bedtime these next two nights – September 19 and 20, 2019 – look eastward for the moon, which shines in front of the constellation Taurus the Bull.

Bruce McClure