In the winter when Orion is high in the southern sky look for the three
stars that make up his belt. The one on your left, toward the east is
called Alnitak and that's the very bright star, center left in this image.
Just south of Alnitak (to the right in this image) is B33, the Horsehead
Nebula and just east (down in the image) is NGC 2024, the Flame Nebula.
It's easy to see why these nebulae have their names.
The overall region of emission nebulosity, the clouds that are reddish in
color, is designated as IC434 in the Index catalog and is only a small part
of the Orion Molecular Cloud Complex which spans pretty much the
entire region of the Orion constellation. There are also a number of
reflection nebulae in the region including NGC 2023 just below and left of
the horse's head and IC 432 left of Alnitak. B33 is known as a dark
nebula. Dark nebulae are so called because they are denser clouds of
gas and dust that block our view of objects behind them; in this case the
emission nebula itself but often star clouds in the Milky Way creating what
appears to be a hole in the galaxy.
The area can be observed visually with a moderate aperture telescope greater
than perhaps 10". The Flame Nebula is quite easy to discern as a hazy
patch of light just outside of the glare of Alnitak. It would be easy
to overlook it so near such a bright star except that the dark dust lanes in
the nebula standout in comparatively stark relief.
The Horsehead is much more difficult to see and normally requires a Hydrogen
Beta filter to see well in such telescopes. I have been able to just
pick it out in telescopes of 17" or larger and only when the field of view
does not include Alnitak.
Telescope: TMB130SS @ f/5.25
Camera: SBIG STL-6303E
Acquisition and Guiding: CCD Autopilot controlling Maxim DL
LRGB Combine Exposures:
Luminance - 15 x 600, Bin 1x1, 2.5 hr
Red - 5x600 Seconds, Bin 1x1
Green - 5x600 Seconds, Bin 1x1
Blue - 5x600 Seconds, Bin 1x1
Ha - 8x1200 Seconds, Bin 1x1, 2.6 hr
Ha - 2x2400 Seconds, Bin 1x1, 1.3 hr
CCD Stack: Calibration, align and
Images Plus: Digital development
Photoshop CS4: Luminance, color combine, levels, curves,
LAB color adjustment, sharpening
Neat Image: Noise reduction.