April 22, 2012: Happy Earth Day, and focus on Perseus (Alpha Persei)

Earth Day flag from Wikipedia

Earth Day flag, from Wikipedia.

Happy Earth Day! I tried to make the most of this day by spending time outdoors: I went for a 4.5–mile run this afternoon, then went out for an extended observing session at night. I located a nearby park and drove over to check it out. It’s pretty convenient: no streetlights and no obstructing trees or houses next to me, though the houses adjacent to the park do have some lights, and occasional cars drove by.

I focused again today on Perseus. I’m really starting to recognize it as well as its position in the sky. Its low in the sky these days, so I want to study it before it disappears for the season (or more precisely, before the sun moves towards Perseus so that daylight obscures it [or even more precisely, before Earth proceeds further in its orbit so that the sun comes between us and Perseus]). It’s quite easy for me to make out δ Per, α Per, and γ Per. I saw Algol (β Per) pretty clearly earlier tonight. I later picked out η Per, ε Per, and even ν Per (3.75m).

View of Alpha Persei Cluster

Simulated view of the Alpha Persei Cluster, created in Stellarium (Wikipedia).

I’ve also been thinking about trying to focus on one star each day. That way I can try to systematically learn the sky, as well as log the stars I’ve seen. And I can read about the star, too. I selected the brightest star in Perseus for today: Alpha Persei (α Per). Also called Mirfak, it’s a second-magnitude star (1.8m) from our distance, though its absolute magnitude of −5.1 shows it to be a rather bright star. It’s 510 light years away. It’s part of an open cluster of stars called the Alpha Persei Cluster. Apparently you can see the cluster with binoculars. I’ll have to try that out some time.

I know I mentioned this before, but I’ve come to really like Corvus. It’s such a nice shape. Monoceros, however, is my new nemesis. The brightest star in it is still only magnitude 3.9. I stared and stared at the locations where its stars should be, but I saw nothing. I few times I could barely imagine I saw a hint of a glimmer, but I couldn’t convince myself that it was real.

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