Star light, star bright may not be a star at all

Wednesday, May 13, 2015

Who remembers the little rhyme, "Star light, Star bright, first star I see tonight. Wish I may, wish I might, have the wish I wish tonight"?

Who can forget waiting outside for it to get dark so you could be the first one to spot the "wishing star" and have your wish granted. Scanning the sky from right to left, up and down just to be able to find that star.

Well, if you are still wishing on stars, be careful. Because the first star you see these warming spring evenings may not be a star at all, it could be a planet.

Above the western horizon about an hour after local sunset two very bright objects will appear. The lower of the two is the planet Venus. The other -- slightly higher and to the left--is almost-as-bright Jupiter.

The pair have been moving closer to each other since early March and will have a spectacular meeting just above the western horizon on June 30.

Another planet you might be able to spot is tiny Mercury. It will be found by drawing a line from Jupiter, through Venus, and down to the horizon.

The very small dot of the planet is only about six degrees above the horizon. Keep in mind that your clenched fist held at arms length is about 10 degrees. Since it will be lost in the after-glow of sunset and any thin clouds along the horizon, using binoculars will be essential to finding it.

Don't wait too long for an opportunity to find Mercury. It has passed its greatest elongation--furthest distance from the Sun--and is now headed back down toward the horizon and will be lower each day making observing more difficult as the days pass.

If you have the patience to wait around -- or nothing else better to do -- start scanning above the eastern horizon at about 10:00 pm MDT for another planet, this time the ringed-planet, Saturn.

It is beginning a five-month period of visibility in our evening sky. It has been visible in the early morning sky since December of last year.

Even though it is above the horizon, the best time for viewing -- at least right now -- is still after midnight when the planet is almost overhead. That gets it out of the atmospheric soup near the horizon. It can be seen in binoculars, but cannot really be observed in all of its ringed glory without a telescope.

Now is a great time for observing Saturn because the ring plane is open about 24 degrees to our light of sight. Unlike the appearance in 2009 when the ring plane was level with our line of sight making it just as good as invisible.

It will be at opposition, or opposite the Sun, on Friday, May 22. At opposition, Saturn will be above the horizon and visible all night from sunset to sunrise. More about Saturn later.

SKYWATCH: Third-quarter moon, Monday, May 11. A very skinny moon makes a very close visit to the outer ice-giant planet Uranus about an hour before sunrise on May 15. The pale, blue-green dot to the upper left of the moon is the planet. Binoculars will put them both in the same field-of-view (FOV), but a telescope -- while not putting them both in the same FOV, will get you a look at the planet all by itself.

NEXT WEEK: Saturn plays with the Scorpion, and more astronomical blathering.

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