Galileo observed the Praesepe nebula in 1610. Praesepe, which is Latin for manger, had been seen in the sky and recorded since ancient times, but before Galileo’s observations, was always described as a little cloud or mist. Through a telescope the true nature of Praesepe was revealed – a cluster of sparkling stars. Praesepe is now known as the Beehive Cluster. Galileo counted 36 stars in the cluster, and observations supported those he made of the Pleiades cluster and of the Milky Way. Before 1610, the known universe had contained barely a few thousand stars. Galileo’s discovery of “innumerable fixed stars” showed the power of the new telescope technology.
Left: Galileo’s sketch of the stars in the Beehive Cluster (Image Credit: Octavo Corp./Warnock Library)
What did YOU See with MicroObservatory?
Can you confirm Galileo’s observation of the Beehive as a star cluster rather than a nebula? If so, can you beat his star count of 36? You have two advantages using MicroObservatory over Galileo’s “spyglass.” The MicroObservatory telescopes are bigger, so can gather more light from faint stars. The telescopes are also equipped with an electronic detector that collects and stores the light.
Above: Archive MicroObservatory image of the Beehive.
To see the Beehive in more detail, you may want to open your image in our MicroObservatory image processing software. You can also compare the Beehive with the Pleiades star cluster in the Galileo activity.
The Beehive - 400 years later
The Beehive is a cluster of around 350 stars. At an age of 750 million years, the stars of the Beehive are much older than those in the Pleiades cluster, and some are already in an advanced stage of evolution. For stars, the bigger and brighter they are, the shorter their lifespan. The biggest and brightest stars of the Beehive, which had been similar to those that light up the Orion nebula (another of Galileo’s objects), have long since used up their nuclear fuel. Because all the stars in the Beehive were born at the same time from the same nebula, this cluster and others like it are very important laboratories for astronomers to study the evolution and lifecycle of stars.
Above: A colorized image of the Beehive. (Image credit: Sloan Digital Sky Survey)
Find Out More
2009 is International Year of Astronomy, chosen to commemorate the 400th anniversary of Galileo’s discoveries with the telescope. Find out what else is happening by visiting these web sites:
The United States national site for International Year of Astronomy.
For more information on the Sloan Digital Sky Survey, go to:
To take images of The Pleiades star cluster and the Orion Nebula using microObservatory, go back to the Galileo menu:
Take a look at the full list of objects in MicroObservatory’s Galileo activity, and see how our understanding has evolved over the last four centuries.