Greetings, stargazers.
It feels great to be back on standard time and not have to leave the house before sunrise. I know some of you are not liking the early evening darkness, but I hope Colorado can join Arizona and Hawaii and just stay on standard time from now on.
Last month, I reviewed the mythological story surrounding the family of Andromeda, the “chained woman.” That tale rambled across a half dozen constellations besides Andromeda, with Perseus being the hero that rescues and then marries her. Perseus defeated the sea monster because he happened to have the head of the Gorgon Medusa in his knapsack. Anyone who gazed upon her head was turned to stone. Perseus was able to cut off Medusa’s head in a previous adventure by approaching her while only looking at her reflection.
Tonight, the constellation Perseus is rising in the northeastern sky after sunset. It follows the “W” of Cassiopeia, that now appears a bit sideways in the sky. I can never find a discernible pattern resembling a hero in the stars of Perseus. I just know they are the set of stars between Cassiopeia, which is a bit higher in the sky right now, and the bright star Capella that rises a bit later in the more recognizable constellation of Auriga.
Useful links
Perseus
https://en.wikipedia.org/wiki/Perseus_(constellation)
Algol
https://en.wikipedia.org/wiki/Algol
Double Cluster
https://en.wikipedia.org/wiki/Double_Cluster
Astronomy picture of the day
An Astronomer’s forecast for Durango
http://www.cleardarksky.com/c/DrngoCOkey.html?1
Old Fort Lewis Observatory
http://www.fortlewis.edu/observatory
hakes_c@fortlewis.edu
None of the stars in Perseus are very bright. Mirfak is the brightest, but it is only magnitude 1.79. Although not quite as bright, the variable star Algol, also called the Demon star, is more notable. Often depicted as Medusa’s eye in artwork, Algol is a multiple star system with an overall magnitude of 2.1. As they orbit each other, the larger, but dimmer star eclipses the smaller, brighter star for approximately 10 hours every 69 hours. During this eclipse, the magnitude changes from 2.1 to 3.4, which represents a decrease in overall brightness by a factor of 3.3 times. This “winking” effect is one of the most visible to the naked eye in the entire sky. I trust you won’t be turned to stone if you try to observe one of these eclipses. There is a third star in the system, but because it is much smaller and dimmer than the other two, you would need a sensitive photometer to discern eclipses from that one.
Between Perseus and Cassiopeia, but within the boundaries of Perseus is what is called the Double Cluster. It is often associated with the jeweled handle of Perseus’ upraised sword. Open clusters NGC 869 and NGC 884 are visible to the naked eye as adjacent dim fuzzy patches. Through binoculars or a telescope at low power, this pair includes two of the most beautiful open clusters you can easily see. These relatively young clusters both contain numerous bright blue-white stars. Surprisingly, the pair were not included in Charles Messier’s list of fuzzy things that aren’t comets. But M34, a less spectacular open cluster also in Perseus, did make the list.
From west to east, Saturn, Jupiter and Mars are lined up nicely across the southern sky along the ecliptic. All three are in an excellent position for viewing through a telescope. Mars is rising just after sunset and will reach opposition on Dec. 8. Its distance from Earth varies much more than Jupiter or Saturn, and it is only this close and bright every two years. Uranus is not typically considered one of the “naked eye” planets, but in a dark place such as can easily be found here away from street lights, it is a relatively easy thing to see. But you will want to use a star chart or electronic star-finder app to locate Uranus because this magnitude 5.7 planet will be one of the dimmer points of light along the ecliptic.
Charles Hakes teaches in the physics and engineering department at Fort Lewis College and is the director of the Fort Lewis Observatory.
