A week of easily seen meet-ups

Wednesday, April 22, 2015

My original intention for this week was to discus the planet Venus passing through the constellation Taurus, the Bull. But I think I will hold that off for a week because next week the bright planet will be within binocular range of the Crab Nebula, the first object French comet hunter Charles Messier put on his list of things that were not comets, M-1.

Instead this week I think we will turn our attention to a few other easily seen meet-ups with the moon, a planet, and a bright star.

I have often been asked why does the moon keep meeting with these same planets and stars each month. Well, do you remember our discussion of the ecliptic, the path the Sun appears to follow against the background stars -- you do remember that the Sun does not move, it is just a figure of speech.

Well, the planets follow that same path as does the moon and Sun as they orbit Earth, so all of them seem to be stuck on the same celestial super-highway and keep meeting each other every month.

This month we have three such meetings.

First, on Saturday, April 25, the moon and Jupiter will be in the same area of sky that is near the nice little open star cluster M-44, the Beehive.

Be outside about an hour after local sunset looking south almost overhead. Finding the moon won't be a problem, neither will be finding the planet Jupiter. Finding the Beehive will be a little more difficult.

Since the moon is at first-quarter its brightness may wash out the cluster, although, from a dark-sky location it may be possible, it will be very easy to locate it using a pair of binoculars. The cluster is located to the right of Jupiter.

Binoculars are probably the instrument of choice rather than a telescope. However the cluster will probably fit inside a telescopic field of view on a small telescope. Use of a large scope is still possible, but you will need to move it around a bit to get a look at the while cluster.

Of course, viewing the moon and Jupiter with a telescope is always enjoyable, especially when the moon is at first-quarter. The line of shadow and light--called the terminator--runs right through some interesting craters on the lunar face and are worth a look.

What with the temperature getting more bearable these spring evenings, it might be possible to spend a few hours making a tour.

If it is cloudy on Saturday evening just hold your viewing session over until Sunday evening. Local sunset isn't until after 1930 hours so it is staying light longer.

The moon has moved on from being near Jupiter to a location that is between the planet and the bright star, Regulus, in the constellation of Leo, the Lion.

Regulus is the dot under the giant, backwards question mark that indicates Leo's head and mane. Regulus means "Little king" in Latin. More about Leo next week.

The third, and final, meet-up this week is on Monday evening when the moon has moved on to stand much closer and almost directly under Regulus

SKYWATCH: First-quarter moon on Sunday, April 25. If you have a very flat, unobstructed western horizon you might be out about 45 minutes to an hour after local sunset with binoculars looking for the tiny, bright spot that is the planet Mercury. Start looking almost directly above where the Sun sat. If you can't find it today, keep looking as it rises higher each evening toward a nice conjunction with the Pleiades star cluster on May 1.

NEXT WEEK: More about Leo and more astronomical blathering.

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