The area around the "sword" in the winter constellation Orion is surely one of the richest parts of the night sky for astronomers. The magnificent Orion Nebula (M42) is the showpiece in this area, but there is a great deal more to see. If the eye wanders north from M42 it first encounters the comma shaped emission nebula M43, just on the edge of the great nebula and seen in this photo at the bottom left corner. Continuing north, the sparkling star cluster NGC 1981 grabs the attention. It is seen in the upper right corner of this photo. With all the glitter and glamour, one might easily overlook NGC 1977, commonly called the Running Man Nebula.
NGC 1977 is a reflection nebula. It is composed of gas and dust from the same immense interstellar cloud that forms the Orion Nebula and the nearby Horsehead and Flame nebulas. The cloud is illuminated by light from the bright stars within, and partly obscured by tendrils of dark dust.
This image is a composite of 24 exposures at ISO 400, each lasting five minutes, acquired on the night of January 31, 2009. The camera used was a Canon Digital Rebel XT, and it was used without a lens, attached instead to the prime focus of an 8 inch f/4.9 newtonian reflector telescope.
When I acquired these exposures I had trouble processing them to produce an image. The results contained a severe and unnatural gradient that resisted my attempts at correction. I filed the exposures away and forgot about them. More recently I retrieved them and had a second look. On my first attempt I had employed a more "push-button" approach to processing the frames, but this time I took it step by step, reviewing the results as I progressed. It soon became readily apparent that the unnatural gradient had been introduced by a particular processing step, and the solution presented itself. This image is the result.
Equipment and software:
Telescope: Orion 203mm f/4.9 newtonian reflector
Guide scope: Orion 80mm f/11.2 achromatic refractor
Mount: Orion Atlas EQ-G
Imaging camera: Canon Digital Rebel XT (EOS 350D)
Guiding camera: Meade DSI-C
Mount control software: Cartes du Ciel, EQMOD
Autoguiding software: PHD Guiding (ASCOM pulse guiding)
Raw frame processing software: Iris
Image finishing software: Photoshop CS2
