Fall officially began on September 23. This time of year, as observers look to east after the sun sets, you see the constellations of Andromeda and Pegasus well up in the east.
In mythology Pegasus is the winged horse. In some versions of the myth, Athena tamed Pegasus then gave him to Perseus who flew to Ethiopia to help Andromeda. Pegasus is one of the 48 constellations listed by the second century astronomer Ptolemy and is one of the 88 constellations recognized today.
The constellation of Pegasus is known for the Great Square of Pegasus, a familiar group of stars called an asterism, made up of four stars forming a large square. The stars known as Alpherratz, Markab, Scheat and Algenib form the four corners. Pegasus is the seventh largest constellation in size.
This fall, a comet, C/2018 W2 (Africano) may be seen passing through neighboring constellation of Andromeda and beginning September 26 through September 29, the comet will pass through the southeastern portion of Pegasus just above the star Algenib. After that it will pass southwards into Pisces and Aquarius in October.
The closest approach to the Earth of comet Africano will be on September 27 at a safe distance of about 46 million miles
The comet was first discovered in November 2018 by astronomer B. M. Africano. At the time the comet was a very dim magnitude 20. It’s expected to reach about eight magnitude at it brightest in mid September.
Although this comet will not reach naked-eye visibility, it may be seen with binoculars or a small telescope.