Happy birthday, Galileo, once again

Oops, Grandpa always said, confession is good for the soul, but sometimes bad for the reputation. That is what happens when you don't pay attention to what page you are on when you write things in your calendar.

Last week I said Galileo's birthday was on Jan. 15, it isn't, it is on Feb. 15, that is the day we can celebrate his 450th birthday. Any reason for a party I guess.

Now, where was I? Oh yes, the night sky. Even if you haven't noticed, the winter sky in the Northern Hemisphere is the home to far more bright stars than any other time of the year. I have to say "Northern," because right now it is summer in the Southern Hemisphere.

A couple of weeks ago we looked at the Winter Hexagon, or Circle, which contains six of the brightest stars in the night sky -- seven if you count Pollux in Gemini -- but that is just seven stars, why are there so many other bight stars in the northern hemisphere's winter sky?

As with many other things we must say location, location, location.

At present in our early evening sky we are looking along the plane of our home galaxy, the Milky Way. Thus it is like looking along the flat width of a cookie held at eye level, held flat, parallel to the floor.

Our Sun is located in what is called the "Orion Spur" of the galaxy, it is an offshoot of the Perseus Arm, and this particular area happens to contain a lot of bright stars.

In our northern summer skies we are looking at the center of our galaxy which is crammed with stars of all kinds and sizes, but there is also a lot of dust and other stuff that tends to block our view and dims the light we see.

In the spring and autumn we are looking out of the plane, up -- or down -- and away from the flat surface. Out and away into inter-galactic space where there are few stars at all.

SKYWATCH: Third-quarter moon on Friday, Jan. 24. There are numerous conjunctions of the moon and planets this week, not to mention several more in the months to come.

If we throw in four lunar and a solar eclipse, we are going to have a very busy astronomical year. Tomorrow morning, Thursday, Jan. 23, there will be a nice meeting of the bright star Spica with the moon and the planet Mars.

Look at about 2 a.m. MST above the southeastern horizon. Spica will be less than one degree away from the moon -- about the width of the moon which will make a nice sight in binoculars. Just off the upper edge of the field of view, if you put the moon and Spica at the bottom, will be the reddish planet Mars. An even better conjunction of the moon and a planet will be on Saturday morning, Jan. 25, when the moon and Saturn will be even closer, look at about 5 a.m. MST. On the morning of Tuesday, Jan. 28 we will have a double-header. Again in the southeast about an hour before sunrise (this won't be too bad, because sunrise is a little after 7 a.m. MST) for a very skinny moon and a very bright planet Venus which has just passed between Earth and the Sun and is now making an appearance in the morning sky. Then, look up and right past Saturn for our old friends Mars and Spica who are still hanging around after the moon passed between them last week. They will both be in the same field of binocular view.

NEXT WEEK: More lunar and planetary meetings, and more astronomical blathering.