When Comet ISON approached late 2013 it promised to be the brightest comet ever, and most visible. But so far as comets come and go the most notable is Halley’s Comet which has an orbit of 75 to 76 years and is the only short term comet that is visible to the naked eye. But what about other comets? There have been some comets throughout history that have been quite spectacular.
For those among us who don’t understand the importance of brightness it is the ability to see it in the night sky. The lower a magnitude it has, the easier the object is to see. If the moon had a high magnitude, we would still be able to see it, but the details visible to us would be far less detailed.
I can still remember as a young child when Halley’s comet last paid us a visit. I was awestruck, to say the least. It was a magnificent sight to behold. But now as an adult, with the prospect that I may not get a chance to witness it again, I now look for other comets, generally long period comets to take a peek at. I must admit that I was surprised to learn that Halley’s isn’t that bright at all. Especially hen compared to some of the brightest comets ever.
The two brightest comets in recorded history occurred almost two thousand years apart. They both had very close perihelion’s (the point of closest approach to the sun) and a negative magnitude. A negative magnitude signifies that it is extremely bright.
The first of these comets, and as far as some regard as the brightest, was Caesar’s Comet of 44BC. It was said to have appeared at the death of Julius Caesar and was visible for seven days. Many writers of the day claimed it was sent to carry the soul of Caesar off to make him a star to watch over the forum. Historians and physicists believe this comet may have been -4 magnitude.
The second comet in contention to be brightest was the Great Comet of 1882. It had a negative magnitude of -7 and was bright enough to be visible next to the sun during it’s perihelion.
It is difficult to compare comets from centuries ago as the scientific apparatus used to detect brightness is a relative new invention. Historians and physicists must rely on eye witness accounts from the day and draw their conclusions from that. Either way, whether it was Caesars Comet or the Great Comet of 1882 that was the brightest comet ever, both would have been a magnificent sight to see.