We are still blessed with the magnificent sight of Orion moving across the Southern horizon during February. Orion’s Belt consists of three very bright stars, Alnitak, Alnilam and Mintaka, with Alnitak being the east most (left) star of the three.
Although most astronomers are aware of the proximity of the Horsehead and Flame nebulae to Alnitak (Alnitak is always a difficult star to deal with in processing Horsehead wide-fields) – what is not generally appreciated is the large amount of faint emission and reflection nebulosity in the region as a whole.
The accompanying image (which made the both the cover, and centre two-page spread of the October 2007 issue of Practical Astronomer) comprises 4 hours and 45 minutes worth of RGB data in 900 and 1,000 second subs. No H-alpha data was taken due to bad weather conditions.
It is clear from the image that a lot more data needs to be taken to bring out all that faint nebulosity lying in Orion’s Belt. This needs at least 4-hours worth of H-alpha using 20-minute subs, and the same using both H-beta and OIII filters as well. I hope to be able to get the narrowband data together this year – weather of course permitting .
Give this region a try – you need a big (3-degree) field of view to get all the Belt stars in the frame, and you can see you will need a LOT of total exposure time. Very best of luck to you in your attempts at imaging this fascinating (and difficult) region.