Tuesday, May 19, 2009

Castor, Izar, More Saturn

I was out tonight for another nice hour or so of stargazing. I spent some time looking for M67 at the bottom of Cancer, but couldn't find it. So, I then picked my usual starter and spent some time looking at Saturn. I thought I saw another moon again, but only one this time, just to the left of the (inverted) rings. After checking out the Sky and Telescope Saturn Moon tool I determined that it was probably Rhea. I may have been imagining it as I saw it best with averted gaze, but I'm pretty sure it was there.

The other day I read that, as far as multiple star systems go, some are more difficult than others to "split" and a good test of your scope's abilities is the binary star Izar (aka Epsilon Boötis) in the constellation Bootes, which is fairly high high in the sky during the spring. So, after consulting my S&T star chart and figuring out which star that was I gave it a try. I was very pleased to see that I could make out both stars in the Izar system. One of them was definitely bigger and brighter than the other, and the bigger one really outshone the dimmer one. It was much harder to pick out than other binaries I've seen, but it was definitely visible at 140x.

This picture of Izar came from this site. There is some good information there in Izar as well.

I wanted to compare Izar to something reputed to be a bit easier to I pointed the scope at Castor, which is one of the two main stars at the head of Gemini. Castor was much easier to split than Izar. The interesting thing about Castor is that it isn't just a binary system. In fact it is a solar system made up of 3 pairs of binaries, making 6 stars altogether in one system. My scope could only make out 2 stars, though, at 140x.

That's about it, nothing too exciting. I'm still pleased about Izar, though. The 120ST is noted to have some variability in quality. The objective lens is not collimatable, so you're pretty much stuck with what you have. The fact that I could split Izar makes me feel pretty good about the particular scope I have.

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