Five prominent stars in the northern sky outline a huge capital letter "M" or a "W"- depending on how you look at it. This is the constellation Cassiopeia.
Cassiopeia has to be one of the most easily recognized and well-known star groups in the sky. The Big Dipper is likely first, and in second place is maybe Orion or Cassiopeia.
As Cassiopeia makes its daily spin about the North Celestial pole- the point right by the North Star around which the whole shebang over our heads seems to revolve- the "M" becomes a "W" 12 hours later, and vice-versa. Of course at certain positions the "M" or "W" seems to be standing on one side.
On mid-Autumn evenings, The "M" shape reaches the point where it is oriented correctly, high up in the northern sky.
Greek astronomer Ptolmey listed Cassiopeia among 48 constellations, in the 2nd Century. Some view the outline of the constellation as a chair, or throne, upon which the Queen sits.
In Greek mythology, Cassiopeia was a queen; her husband, King Cepheus, is immortalized next to her with his own constellation.
The Queen is not without her gems. There are numerous interesting stars and star clusters within the borders. Actually, what star ISN’T interesting?
First, here’s two you WON’T see!
The first is a star that erupted into a supernova in 1572, becoming so bright it was visible in daylight. The exploding star gradually faded away. The famed Danish Astronomer Tycho Brahe carefully chronicled the event for us.
The second star is none other than the Sun! What? Yes, the Sun- but you have to be looking from the direction of Alpha Centauri, the closest star system to our Sun. Alpha Centauri is exactly opposite in the sky from Cassiopeia and is thus found in the far southern sky, best seen below our equator. From Alpha Centauri the Sun would appear as a bright yellowish star, magnitude 0.5, the brightest star in Cassiopeia.
Two of the fainter stars visible to unaided eyes are among the most luminous stars known. At magnitude +4.5, Rho Cassiopeiae gives out 550,000 times as much light as the Sun. It is a rare yellow "hyper giant", among only seven of this type known. Another of the seven is also in Cassiopeia, +5th magnitude V509 Cassiopeia .
The Milky Way Band passes through Cassiopeia, providing a rich background of dim stars and star clusters waiting your search with binoculars or telescope. M52 and M103 are two large open clusters here.
The brightest star in the "W" is known as Shedir, or Alpha Cassiopeia . Close by is the famous Double Cluster, actually within the neighboring constellation Perseus. Seen with unaided eyes on a dark night as a double "smudge," the clusters resolve into two dense patches of fine stars in binoculars.
Full Moon is on Oct. 18.
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Keep looking up!