The Great Nebula in Orion
(Messier 42 . NGC 1976 . Sharpless 2-281)
Perhaps the most well known
celestial object in the night sky is The Great Nebula in the belt of the
constellation Orion,
the Hunter. Visible to the naked eye, this massive nebula is a relatively close
1500 light-years distance, and busily in the process of forming new stars. The
Great Nebula is in-fact the
brightest part of a far larger and much fainter nebula that covers more
than 10 degrees of our night sky.
The Great Nebula is mostly illuminated
from star light produced by the four young stars at the crux of the nebula just
above centre image. These four stars, collectively known as the Trapezium, appear to the naked-eye as a single star
named Theta-1 Orionis.
The Trapezium stars are young stars which have formed from the nebula. Since
birth their stellar winds have blown the nebula into the partial bubble shape we
see today. The Great Nebula was first discovered by Peiresc, 159 years before it become the 42nd object
(M42) in the famous Messier list.
Paul Mayo
| Image Details | Messier 42 - 20060319 |
| Image Field of View | approx. 48 arc-minutes wide. |
| Telescope | 12-inch f/5 newtonian telescope. |
| Guiding | hand guided with 4.5-inch guide-scope. |
| Camera |
Canon EOS 300D Digital - Hα enabled. |
| Exposures | Main
Image; 6 x 180 second exposures @ ISO200 with dark frame subtraction, bias and flat-fielded. Image used to mask core; 3 x 15 second exposures @ ISO200 |
| Total Exposure time | 18-minutes. |
| Filter/equipment | Used Baader Multi-purpose Coma Corrector. |
| Sky Conditions | Seeing: 7.5/10. Wind: 3/10. Moisture: 3/10 |
| Ambient Temperature | 23°C |
| Notes | Moon Rising ends imaging session. |
| Processing | Iris, Photoshop, Noiseware CE. |
(C) Copyright 2006 Paul Mayo.
paulm@skylab.com.au