Tradition over Substance
Charles Messier’s famous list of deep sky objects has a few quirks. Messier 73 is one of them. When Messier viewed the four stars (above the label in the drawing) on October 4 & 5, 1780, he believed that he saw some faint nebulosity and thus assigned it as an object that could be confused for a comet (Messier was a comet hunter). We now know that there is no nebulosity at this location. His error can easily be blamed on the quality of the telescope he was using which blended the light of the close stars into a false nebula.
The four stars are not a gravitationally bound star-cluster or even a multiple-star system, just four stars of chance alignment. The best one could call it is an Asterism, but even that is being kind. Regardless of its true nature it is still on the Messier list and thus is viewed on a regular basis by amateur astronomers around the world. More surprising was that these four stars were assigned an NGC number (6994) even though by then they were aware of Messier’s error and that no nebulosity existed. I guess M73 is worth a drawing for historical reasons even though it is of no true astronomical importance.
To view additional astronomy drawings visit: www.orrastrodrawings.com
Tradition over Substance
Charles Messier’s famous list of deep sky objects has a few quirks. Messier 73 is one of them. When Messier viewed the four stars (above the label in the drawing) on October 4 & 5, 1780, he believed that he saw some faint nebulosity and thus assigned it as an object that could be confused for a comet (Messier was a comet hunter). We now know that there is no nebulosity at this location. His error can easily be blamed on the quality of the telescope he was using which blended the light of the close stars into a false nebula.
The four stars are not a gravitationally bound star-cluster or even a multiple-star system, just four stars of chance alignment. The best one could call it is an Asterism, but even that is being kind. Regardless of its true nature it is still on the Messier list and thus is viewed on a regular basis by amateur astronomers around the world. More surprising was that these four stars were assigned an NGC number (6994) even though by then they were aware of Messier’s error and that no nebulosity existed. I guess M73 is worth a drawing for historical reasons even though it is of no true astronomical importance.
To view additional astronomy drawings visit: www.orrastrodrawings.com