The "Monkey Head" Nebula...

Object: NGC 2175
Type: Emission Nebula
Distance: 7200 light years
Constellation: Orion
Date: 16 January 2008
Equipment: SXV-H9, Vixen ED114 refractor (f.l. 600mm)
Subframes: 80 x 120 second 2x2 binned subframes, 16 darks, 16 flats/flat darks, calibrated and stacked in AIP4Win. Final processing in AstroArt and "photographic unsharp mask" and colours applied in PaintShop Pro7.

I hadn't come across the nickname "Monkey Head" for this particular object until I saw this post by "Paramount" on the Society of Popular Astronomy's Gallery page. I think I can just make out an enigmatic simian grin under the central star of a nose, with the darker areas either side of the star representing two eyes. Maybe.

The tracking was a little off but the deconvolution tool in AstroArt rounded the slightly elliptical stars up quite well - this time, I'd taken enough subs so that the deconvolution process didn't introduce all sorts of artifacts into the image by amplifying high levels of background noise.

I also had a play with Jerry Lodriguss's "unsharp mask" technique (link as above). This boosted the contrast in the image quite nicely, without increasing graininess or putting dark rings around the stars, and it's a technique I'll definitely be looking to use for extended objects like this in future.

I couldn't resist colourising the monochrome result and this worked out quite well on an image compiled from a smaller stack of subs that gave a slightly wider field (the object had drifted quite a way in the field during the course of the evening).

Click on either image to enlarge.

In the literature, there seems to be some confusion over whether the designation of NGC 2175 is referring to the cluster or its nebula. Stephen O'Meara puts us straight in his excellent book, Hidden Treasures: an excerpt that gives lots of interesting information about this oft-overlooked object can be found here.