SkyCaramba weekly astronomy blog for the week ending February 18, 2012
A dim star cluster in a dim constellation rises on February evenings between Gemini and Leo. M44, also called Praesepe and the Beehive Cluster, is in the heart of Cancer the crab. Many people looking with just the naked eye can’t tell it’s there. To others, it looks like a fuzzy spot on the sky. Point binoculars at it and what a surprise! There are a few hundred stars in this cluster.
It’s called M44 because it was the 44th fuzzy object on a list made by astronomer Charles Messier. He made the list of fixed fuzzy objects so he could tell quickly whether he found something new that might be moving. Messier could then maximize his time hunting for comets. Most of the objects in Messier’s list are easy to mistake for comets. Astronomers generally feel M44 is not, so some people wonder why Messier included M44 in his list.
According to the National Audubon Society Field Guide to the Night Sky, some ancients thought this particular fuzzy spot was a thin spot in the floor of heaven. Souls passed through it to Earth to be born. They called it the Gate of Men.
When Galileo pointed his telescope at it, he knew there are more stars than the naked eye can see. The stars of Praesepe reminded the early telescope owners of bees at a beehive. Thus the name Beehive Cluster.
The name Praesepe goes back much farther. It’s the Latin word for cradle or manger and was used for this spot in the sky more than 2,000 years ago. Two nearby stars were called the northern and southern donkeys. They were said to eat from this manger.
The Beehive is a point along a sort of highway in the sky called the ecliptic. The sun, moon, and all the planets cross the sky close to the ecliptic. The moon passed by the Beehive on February 6 and will again on March 5. Mars passed through in early October 2011. Mercury will stop by in early July 2012 and again in mid August. Venus will visit the cluster in mid September. Mars will visit again in September 2013.
This cluster of stars is about 550 light years from Earth. That’s not far in galactic terms. It’s fairly bright compared to most star clusters visible from Earth. That makes it easier for astronomers to study. The variety of stars found in a single cluster is intriguing. There are red giants and white dwarves in the Beehive. Scientists want to know how so many different stars can come into existence in the same cluster.
The best magnified views of M44 are at low power. It’s too wide to fit in a high power view. And high powers aren’t best for viewing star clusters anyway unless you’re interested in getting a close view of particular stars in it.
Look for the dim stars of Cancer between Gemini and Leo. They’re up all night this time of year. ¡SkyCaramba!