The Square of Pegasus ( an asterism of the constellation of Andromeda, the Chained Maiden which is made up of four stars of nearly equal brightness namely: Scheat, Alpheratz, Markab, and Algenib) takes center stage in the Philippine night sky after sunset, which is a sign of the arrival of the northern fall. Northeast of it lies the Andromeda Galaxy (M31), the closest large spiral galaxy to the Milky Way Galaxy as shown in Figures 1 & 1a. Under clear skies and with the aid of a star map and familiarity with the surrounding background stars, it can be seen as an elongated misty patch with the naked eye and can be easily viewed through binoculars and telescopes. The splendid W formation of stars known as the constellation of Cassiopeia, the wife of King Cepheus and the mother of Andromeda in Greek mythology, lies to the left, while the constellation of Pisces, the Fish can be found at the lower right of Pegasus.

The famous equilateral triangle in the sky, known as the Winter Triangle rises after midnight. The Triangle formed by the stars is composed of Betelgeuse, the supergiant red star and the prominent star of the famous constellation Orion, (the Mighty Hunter), Sirius, the brightest star in the sky of the constellation Canis Major (the Big Dog), and Procyon, the brightest star of the constellation Canis Minor (the Little Dog).

Figure 1

Figure 1a

On 01 October at 7:00 PM, Venus will be found at about 15 degrees above the west southwestern horizon during the month. It will be shining brilliantly at magnitude -4.10 and will lie among the constellation of Libra, the Scale. It will be observable during the entire month.

Also, Saturn and Jupiter will be easily spotted at about 55 and 51 degrees above the south southeastern horizon, shining at magnitudes +0.4 and -2.7, respectively. Both planets will lie among the background stars of the constellation Capricornus, the Sea-Goat. They will remain visible in the night sky throughout the month.

Neptune on the other hand, will be located at about 34degrees above the east southeastern horizon which abode among the background stars of the constellation Aquarius, the Water-Bearer with a magnitudes +7.80. Observing this planet will require a binocular or a telescope and a star map under dark and clear sky conditions.

On the same date and time at 10:00 PM, Uranus will be found 34 degrees above the eastern horizon during the month. It will be glowing at magnitude +5.6 and resides among the stars of the constellation Aries, the Ram.

Mercury and Mars will be difficult to observe due to their proximity to the Sun during the month

Figure 4 shows how to compare apparent magnitudes of celestial bodies such as planets and stars.

Figure 4

OCTOBER 2021

Errata of AGE 2020, page 2 (Errata of AGE 2020 pdf file)