Messier 1. Crab Nebula in Ha-LRGB.

Note
First attempt on M1. Some beany stars in the left down corner but otherwise I am satisfied.

About
The creation of the Crab Nebula corresponds to the bright SN 1054 supernova that was independently recorded by Arabic, Chinese and Japanese astronomers in 1054 AD. The Crab Nebula itself was first observed in 1731 by John Bevis. The nebula was independently rediscovered in 1758 by Charles Messier as he was observing a bright comet. Messier catalogued it as the first entry in his catalogue of comet-like objects. The Earl of Rosse observed the nebula at Birr Castle in 1848, and referred to the object as the Crab Nebula because a drawing he made of it looked like a crab.

In the early 20th century, the analysis of early photographs of the nebula taken several years apart revealed that it was expanding. Tracing the expansion back revealed that the nebula must have become visible on Earth about 900 years ago. Historical records revealed that a new star bright enough to be seen in the daytime had been recorded in the same part of the sky by Chinese astronomers in 1054. Given its great distance, the daytime "guest star" observed by the Chinese could only have been a supernova—a massive, exploding star, having exhausted its supply of energy from nuclear fusion and collapsed in on itself.

Recent analysis of historical records have found that the supernova that created the Crab Nebula probably appeared in April or early May, rising to its maximum brightness of between apparent magnitude −7 and −4.5 (brighter than everything in the night sky except the Moon) by July. The supernova was visible to the naked eye for about two years after its first observation. Thanks to the recorded observations of Far Eastern and Middle Eastern astronomers of 1054, Crab Nebula became the first astronomical object recognized as being connected to a supernova explosion.

In 1973, an analysis of many different methods used to compute the distance to the nebula reached a conclusion of about 6,300 ly. Along its longest visible dimension, it measures about 13 ± 3 ly across.

Processing
CCD Stack and CS5

Exposure
Ha: 9x10 min. Lum: 15x5 min. RGB: 9x5 min

Calibration
Darks, bias and flats.

Filters
Baader LRGB. Baader Ha 7nm.

Cooling temp
-20´ C

Mean FWHM
3.50"

Date
October 24th 2011

Location
Krigslida, Stockholm, Sweden.
N59 06 52.4    E 18 03 54.5

Image aqusition
MaximDL Pro

Scope control
Sky X Pro Native drv, and Maxim DL with Astro-Physics V2 drv.

Telescope
TEC APO 140

Mount
Astro-Physics Mach 1 GTO

Camera
QSI 583 WSG

Guiding
OAG guiding with Lodestar Guider

Focus system
Starlight Micro Touch and Focus MAX.


Inverted B/W image


Image in LRGB




Pure H-alpha