April 26, 2012: Focus on Algol (Beta Persei) and Lynx

It was rather chilly out, and the sky was a bit hazy, but it also looks like today will be the best viewing day for the next several days, so I popped out for a few minutes. A few days ago, I focused on α Persei, so today I decided to focus on β Persei. Not only is it the beta star, but it’s also the lowest from my position so I’m catching it shortly before setting.

I wrote about Algol (β Persei) a few days ago. It’s actually a triple star system (β Persei A, B, and C). As I noted before, we’re in the plane of the orbits of β Per A and B around each other. β Per B is dimmer, and when it passes in front of β Per A, the combined star magnitude drops from 2.1 to 3.4. A and B are only 0.06 astronomical units (the distance from Earth to Sun) apart! That’s closer than Mercury is to the Sun, and only some thirty times the distance from the Earth to the Moon. C is 2.7 AU away, about as far as our asteroid belt is from the Sun.

Computer simulation on how Algol may rotate

Computer simulation on how Algol may rotate

This type of eclipsing binary star, where we happen to be in the orbital plane and so one star periodically eclipses the other, is now called an Algol variable.

I also really tried to see Camelopardalis, the constellation I read about yesterday. No luck — it’s just too faint. Monoceros has a new friend. I also tried to see Lynx, and I was able to just make out α Lincis — the other stars are all too faint. That’s fine — I don’t mind having a single star represent the constellation.

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.