Wednesday, January 25, 2012


I've had one, repeat, one (1!) night with clear skies since I wrote the last post. I did make the best I could of that and hopped in the car armed with binoculars and some idea of what I wanted to look at. I stayed with Orion because, well, because I need to start somewhere.

So I went over what I already knew about it; Betelgeuse, the Orion nebula, and then stayed with Rigel for a minute or two. Realized that I don't really recognize as many constellations as I thought I should and had a look at what little I knew I could name: The big dipper and follow the backside of the "cart" (the Swedish name for it, Karlavagnen, means a cart not a ladle) up until I find Polaris. Okay, check.

Then took the binoculars down and looked up and around. Found a very bright star seemingly alone, straight above me. What is it? Well, here's where my SkyView app came in handy. I pointed it straight up, and it told me the name of the star. What was it? I don't remember. But then tonight, as I was writing this post I used the simple fact that I'm still in the same place, it's the same time of year, and even though it's a cloudy night SkyView doesn't care what the outside looked like. So sitting in my couch I pointed my phone up and, sure enough, there it was. Capella.

Capella is a pretty cool star in that it's not a star at all. It's actually four stars, but the two that you can see (although "they" sure looked like "a" star through binoculars) are two giant stars circling each other very closely. How closely? About the distance of the earth to the sun! Two stars, the smallest of which has a radius of 9 times the sun, circling each other closer than our sun is to us. To put that into perspective, if that can be done, it's... Well, if you're on the surface of the bigger of the two stars and look up at its sister in the sky, it would take up (if my calculations are correct, see picture) 7.5 degrees of the sky, or fifteen times the apparent diameter that the sun has in our sky.

I haven't done trigonometry for quite awhile, but I had help from a Certified Math Teacher who I'm married to who made sure I wasn't getting too far off track in doing the calculations. Once I was done, I tried to find out if there was a way to look up the answer online and found out that someone - of course - has written a Wikipedia article on angular diameter which is used for specifically this. Still, I feel a little bit smarter for figuring out the equation on my (mostly) own instead of googling it.

Now, please - some clear skies!

Sunday, January 8, 2012

Amateur astronomy starts now

New hobby: Amateur astronomy. New function of the blog: Astro log. That's all I have to say about the transition from poker to astronomy.


Step 1 was to buy a pair of binoculars, and I went with a pair of Celestron 15x70 (that is magnification x aperture, or width of the main lens) which are decently heavy but pick up a lot of detail, pictured below. I'll get to buying a telescope eventually, but have now decided that there's plenty to look at and learn before I take that step.

I've had a couple of peeks at the night sky already, but as I'm starting the log tonight, I'll add only tonight's views to it:

Low in the sky, very visible, looked crescent, but hard to tell.

I can't help myself - have to look at Jupiter now that it's so close, despite having done it every time I'm outside and it's clear in the last two weeks. Got a decently still view of it by leaning against the wall to remove jittering of shaking hands. Seeing Jupiter's moons is so. Very. Cool. Looked basically like this (but two on the left and one on the right instead of all four tonight):

Jupiter in binoculars
(Picture courtesy of 10 Minute Astronomy)

It's really very blinding without a filter and I find that it's actually nicer to look at it through a light cover of clouds. But it was a full moon, and I had to give it a look. Note to self: Learn some of the names of the major landmarks. Especially that crater in the "southwest" corner that, as my mom put it, makes it look like it's an orange. Investigation still ongoing.

My first thought was "hey, Mars!" but a quick check using the SkyView app told me differently. What tricked me was the red color, and yes indeed - Betelgeuse is a red supergiant ("the armpit of Orion") ~650 lightyears away. It also twinkled ("cintillated" is apparently the correct term) a lot making it look like it was going through a prism; different colors coming at me but chiefly in red. Looked up the magnitude: A respectable 0.8, making it (incidentally) the 8th brightest star in the sky.

Later at night, clouds had covered the whole sky except for a a thin band on the southern horizon and I thought I saw Betelgeuse again, just over some rooftops; very bright start, much scintillation, but... Apparently not Betelgeuse. Nope, again using SkyView has reference i deduced it had to be Sirius, which it turns out is the brightest star in the sky, with a magnitude of -1.46. The scintillation made this too look like it was going through a prism, with all sorts of colors coming at me (is there something wrong with my binoculars? No, probably not).

Having gone through all this twinkling I formed the hypothesis that stars twinkle more close to the horizon because of the extra atmosphere they have to go through. The link above on twinkling gave me the nod on that guess.

Let's hope for clear skies soon again.