Choosing A Telescope
Telescope Aperture Considerations
Introduction to Planetary Sketching
Refractor Dobsonian Style Mounts
The Bonds: Pioneers of American Astronomy
Saturn's Encke Minima and Encke Division
Nature and Travel Photography
Recommended Astronomy Books
M 1 and Saturn
December 29, 2002 8:55 PM - 9:45 PM, seeing 4-5, transparency 4.5. South is at the bottom.
Astro-Physics 5.1" f/8.35 EDF refractor on homemade Dobsonian-style mount. Magnification 68x-91x.
In late December 2002 and early January 2003 Saturn was near the Crab Nebula, and on the night of January 4-5 2003 it passed in front of the nebula. This sketch was made six days before it transited in front of the nebula. M 1 (NGC 1952) is a Supernova Remnant located in the constellation Taurus. The diameter of the nebula is 6' x 4' and it has a magnitude of 8.4. It is approximately 6,500 light years away.
The Crab Nebula was first discovered by the English physician and amateur astronomer John Bevis in 1731. Charles Messier first observed it on September 12 1758.
Messier described it as a "Nebula above the southern horn of Taurus, which does not contain any stars. Its light is whitish and elongated like a candle flame." This discovery prompted him to compile his famous catalogue of nebula and clusters so that other observers would not confuse them with comets: "What caused me to undertake the catalog was the nebula I discovered above the southern horn of Taurus on Sept. 12, 1758, while observing the comet of that year...This nebula had such a resemblance to a comet, in its form and brightness, that I endeavored to find others, so that astronomers would not confuse these nebulae with comets just beginning to shine."
It was Lord Rosse who gave it the name "The Crab Nebula" in 1844. He saw the extending filaments and referred to them as resembling the legs of a crab.
William Lassell, observing it in December 1852 with his 24" speculum metal reflector, confirmed these filamentary structures: "With 160x it is a very bright nebula, with two or three stars in it, but with 565x...Long filaments run out from all sides and there seems to be a number of minute and faint stars scattered over it; the outlying claws are only just circumscribed by the edge of the field of 6' diameter..."
M 1 was formed by a supernova explosion that occurred in 1054 A.D. It was reported by Chinese observers as "It was visible in the day like Venus, with pointed rays in all four directions. The color was reddish white." It was seen for twenty-three days in the daylight sky.
Through the eyepiece of the 5.1" the nebula is relatively bright, with an irregular shape to it and diffuse near the edge, with a slightly brighter inner portion that resembled a Z shape. The nebula appears light green in color. Saturn showed a light yellow Equatorial Zone, a tan South Tropical Zone, and a green South Polar Region. The Cassini Division was visible on both ansae and in front of the globe, as was the Crepe Ring, although these features do not show up well in the sketch when it was scanned in. Four moons were visible nearby including Titan, Tethys, Dione, and Rhea.