Saturday, March 26, 2011

Messier 1, the Crab Nebula

The image below is a reprocessed version of the Crab Nebula that is posted on my web site.

I took five images of the Crab Nebula one night over a year ago, just to see what it would look like. My intention was to go back and do a proper imaging sequence when I had time. That time never came, and I have probably missed my opportunity to image it this year. As a consolation, I went back to the original five images and reprocessed them using the techniques that I have learned since creating the original.

Messier 1 (Crab Nebula), Epsilon-200 on NJP, 5x180
The Crab Nebula is probably the best known supernova remnant in the sky. Chinese astronomers noted the appearance of a "guest star" on July 4, 1054. The star was four times brighter than Venus, and visible in daylight for 23 days. It was visible to the naked eye at night for 653 days. A number of Native American groups also recorded the event in pictographs.

The debris cloud was discovered in 1731 by John Bevis. Charles Messier found it in 1758 (not realizing that it had been previously discovered), and mistook it for Halley's comet. He soon realized his mistake, and this prompted him to compile his famous catalog of fuzzy objects that are not comets--the Messier Catalog. Messier 1 gained is common name, Crab Nebula, based on a drawing made by Lord Rosse in 1844.

The true nature of the "guest star" was not revealed until the early 20th century, when astronomers compared the results of observations gathered over several years and found that the nebula was expanding. Calculations based partly on the rate of expansion revealed that the event that created the nova was the "guest star" observed by the Chinese in 1054.

1 comment:

  1. I like this one a lot, Rory. M1's on my list, too (like it's on everyone's with a camera and a scope). I took a look with the 15" dob a few weeks ago from the burbs and saw the ghostly glow but not much else. The camera gets the details!