The last two constellations in the 'ocean'
Thursday, September 23, 2010
Have you taken that celestial swim yet? Have you been out to observe Capricornus, Aquarius, and Piscis Austrinus?
The swim, of course, refers to an area of the sky made up of constellations that have some sort of relation to the ocean.
Last week we looked at Capricornus, the Sea Goat, Aquarius, the Water Bearer, and Piscis Austrinus, the Southern Fish with its bright star Fomalhaut, the loneliest star in the sky.
This week we look at the last two constellations in the celestial ocean, Pisces, the Fish, and Cetus, the Whale, or as some have called it the "Sea Monster" relating it to the story of Andromeda and Perseus.
Both constellations are rather dim and difficult to locate. They are composed of third and fourth magnitude stars.
However, tonight there is a marker that will help, or perhaps hinder, the location of the stars.
Pisces, the Fish, is one of the 12 zodiacal constellations and is found along the Ecliptic, the path the sun follows through the sky and tonight it is located just above the eastern horizon.
Unfortunately, an almost-full moon is located right in front of the south (on the right) end of Pisces in an area called "The Circlet" stars arranged in a circle shape marking one of the fish of Pisces.
The brightness of the moon will almost certainly blot out any stars that may be seen, but please note that right below the moon is our old friend, Jupiter. On Friday, Sept. 25, the moon will be out of the way allowing us to return to the area and find the Circlet of Pisces floating just above Jupiter.
Another marker to help locate the fish is the "Great Square of Pegasus." Pisces is a "V" shape running north from the Circlet down and under Pegasus, located high in the east, then back up with a line that points to the middle of the Andromeda constellation.
Our final "fish" will not be readily visible until the end of October. That is Cetus, the Whale.
On Oct. 23, a just-passed full moon will be above an oval shaped group of stars, called the Circlet, that mark the head of the beast.
A slender string of stars connects to a large rectangle forming the body to the right.
Both constellations are difficult to locate, but will give you a sense of accomplishment when they are found. So go take a dip in the celestial ocean. A swim is always refreshing.
SKY WATCH:
Yesterday, at 9:09 a.m MDT the sun crossed the celestial equator headed south marking the autumnal equinox, the first day of autumn for the northern hemisphere and spring for the folks down south. Six hours after that crossing, the moon was full, and the full moon closest to the autumnal equinox is called a harvest moon.
Go outside tonight and for the next two nights about sunset and look east for the rising moon. The harvest moon is noted for its size and brightness. But don't let the size fool you. The moon is the same size as it always is. Don't believe me? Then try this. Hold a dime at arms length up next to the moon as it is rising. Go back out several hours later and put the same dime up next the the moon again. See, it is the same size. The size of a rising moon is an optical illusion, and there is much debate in the scientific community as to just why the moon looks so large when it rises. Any ideas?
NEXT WEEK:
More astronomical blathering.