Time for a celestial swim

Thursday, September 16, 2010

How would you like to take a swim? Well, with the daytime temperatures not as warm as they were last month, there might be an adventurous few who might.

OK, how about an astronomical swim? I can see the confused and quizzical looks on your faces now.

The months of October and November are the "season of the water" astronomically speaking. The water constellations, Capricornus, Aquarius, Pisces, Piscis Austrinus and Cetus have prominence in the evening skies.

Let's start with the easiest, Capricornus or Capricorn, the Sea Goat. It is one of the 12 zodiacal constellations and tonight can be found lurking almost due south behind the moon, that is if the moon does not blot out the stars.

Capricorn has the shape of a boat, a distinct "V" for the hull and a string of stars between to two point stars of the hull for a deck. On Saturday, Sept. 18, the moon is just inside the right end of the boat's hull.

It is a large constellation, about 20 degrees across, about the width of two clenched fists held at arm's length.

If you have a large pair of binoculars or a modest telescope you might find the planet Neptune (another "sea" association) hanging about three degrees just above and slightly left of the left end star of the boat.

Left and slightly up from Capricorn is the second water constellation, Aquarius, the Water Bearer. Another very large constellation (about 36 degrees across).

There are no really distinct shapes that can be made out in Aquarius so it is difficult to find, except on Monday, Sept 20, the moon will be in the big middle of it.

Below and between Capricornus and Aquarius very near the southern horizon is a very non-nondescript constellation called Piscis Austrinus, the Southern Fish. There are 10 or so stars in the constellation, all except one are fourth and fifth magnitude stars, so a very dark-sky place is needed but even then you may not find them.

The one star you will have no trouble finding is first magnitude Fomalhaut, the "Mouth of the Whale." As I have shared before, Fomalhaut caused no small stir among "Lord of the Rings" fans when a Hubble Space Telescope image showed a torus, or ring, around it which had an astounding resemblance to the "Eye of Saroun" from the then popular movies of the same name.

There was no small stir among astronomers, too, as the image from Hubble also showed the first recorded image of an extra-solar planet. There was some question as to which group was more excited.

Due to its location and limited opportunities for visibility, Fomalhaut is often called one of the loneliest stars, as there are often no other stars to be seen around it, including the stars of its own constellation.

We will save the next two "aquatic" constellations until next week.

SKY WATCH:

As Venus leaves the sky in the west, Jupiter joins it in the east accompanied by fellow gas giant planet Uranus. Both giants are visible in the same field of view in binoculars. Look about an hour after sunset.

Want to come to a party? Join me on the evening of Saturday, Sept. 18, in the parking lot of the Dundy County Fairgrounds and we will have a party, that is the night for the "International Look at the Moon" activity. Join thousands of people all around the world as we observe our closest celestial neighbor. Bring your own chips and soft drinks and chairs, I will provide the telescopes.

NEXT WEEK:

Pisces and Cetus, the water constellations and more astronomical blathering.

Respond to this story

Posting a comment requires free registration: