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.

April 16, 2012: Overall sky survey

Diagram of Cassiopeia

Cassiopeia (IAU/Sky & Telescope)

I spent around 15–20 minutes outside today, just studying the overall sky. I was just out in front of my house, which is convenient, but there is a lot of light pollution from street lights and house lights. The trees and other buildings also obstruct much of the sky. But since the view from outside my front door is going to be the most convenient place to stargaze, I want to be familiar with it. Fortunately, the sky was completely clear, and it wasn’t too cold (about 43°F/6°C, with no wind).

My best view is to the south, with good views to the east and west, but obstructions to the north. The nice thing about tonight’s viewing was that the visible constellations represented a part of the sky with which I’m relatively familiar. The first thing I noticed was Mars nice and high in Leo, Sirius visible just above the horizon, and Venus close to setting. Orion, my favorite constellation, was setting. I could see Betelgeuse (α Ori) and the belt (ζ Ori, ε Ori, and δ Ori).

I’ve been trying to start systematically becoming familiar with the constellations, going quadrant by quadrant. I’ve started with “NQ1”, the eighth of the sky between right ascension 0h and 6h and above 0° declination. Most of the stars in this quadrant aren’t really visible at this time of year, since the sun is currently in this quadrant. I did try to focus on Cassiopeia, but it was close to setting. I could clearly see the five bright stars of the “W” asterism: ε Cas, δ Cas, γ Cas, α Cas, and β Cas. I also tried to study Perseus, since it’s a constellation with which I am really not familiar. I could make out four stars that were more or less parallel to the horizon, at about an altitude of 20°; reviewing my charts now, I assume these are δ Per, α Per, γ Per, and η Per. I’ll hope to recognize Perseus better once it’s more visible.

Overall, I think η Per was the dimmest star I saw tonight — it has an apparent magnitude of 3.75, making it a fourth-magnitude star. It’s not bad given the amount of light pollution.