M1 The Crab Nebula

Photo by Pittendreigh
14-inch diameter Schmidt Cassegrain Telescope (SCT) with a focal length of 4,000 mm

M1 was discovered by John Bevis in 1731.

It is a remnant of a supernova that was first recorded on July 4, 1054 A.D. by Chinese astronomers. It consists of the material ejected in the supernova explosion, which has been spread over a volume approximately 10 light years in diameter, and is still expanding at the very high velocity of about 1,000 miles per second.

The central star is actually a rotating neutron star and is called a pulsar (NP 0532), which rotates once every 0.033 seconds. Now THAT is FAST!!!

M 1 became known as the Crab Nebula after the Earl of Rosse observed the nebula at Birr Castle in the 1840s, and referred to a drawing he made of the nebula, which looked like a crab.


HOW TO FIND IT, WITHOUT A COMPUTER:

I have given this a difficulty rating of 2, because it has good guide stars. M1, however, is very dim, and as such, it is a difficult Level 2 to find. Just be patient and be sure you have good skies on you first try.

1. Find the "V" shaped section of Taurus, sometimes called the Hyades.

2. Extending the line of the "V" with the brightest star, Aldebaran, continue until you locate Zeta Tauri.

3. Scan the area near Zeta. In your viewfinder, try to locate a triangle

of stars, with Zeta being part of the triangle. M1 is within that triangle area. Because it is rather dim, this is a good nebula to use a "scan and stop" method of moving the telescope, then pausing for several seconds to let your eye absorb the light, then moving and pausing again.

WHAT TO LOOK FOR:

Don't look for the photographs you've seen, with its wisps and filaments. Look for an oblong nebula with no detail.

Once you have located it, then take time to let your eyes adjust. See if you can indeed find any hints of the filaments seen in photographs. Binoculars should reveal M1 with no problem, as long as the sky conditions are good. The filaments and wisps can be seen in an 8 inch reflector. The crab-like shape of the nebula can be discerned in a 10 or 12 inch reflector.

SELECTED PERSONAL OBSERVATIONS

October 3, 1967:
With 8 inch, f/8 Cave Optical Reflector. My initial impression was one of disappointment. I found it very difficult to locate and it was not what I had imagined after seeing familiar photos of the Crab Nebula. I would describe this as a dusty smudge of light.

January 16, 1969:
Jason binoculars 7x15x 35
Very challenging for me. M 1 appears as an oblong, faint, diffuse patch of light lying approximately one degree northwest of the third magnitude star Zeta Tauri. The nebula is detectable with direct vision, but best seen with averted vision, or as Dad would say, "averted imagination."

April 1, 1969
0210 GMT
Questar 3.5
Averted vision discerns small variations in the brightness along the edges of the diffuse patch.

April 14, 2006
0100 UTC
Photographed Crab using 14-inch diameter Schmidt Cassegrain Telescope (SCT) with a focal length of 4,000 mm. Viewed visually with 85-mm diameter APO refractor telescope. Nice detail on a clear night. Some slight detail is discerned.