NGC 2261: Hubble's Variable Nebula

Click on image for larger version.

Comet!? No- this object was put into the correct category as a diffuse nebula. The bright star at the tip of the cloud of gas is called R Monocerotis. It is a variable star that is actually in the background of the this cloud of gas. The gas cloud is around 1 light year in extent and due to the variability of R Mon- the entire nebula changes in its brightness. However, R Mon is mysterious because the mechanism of its variations is uncertain. The most accepted explanation is that there exist clouds of gas and dust very close to R Mon; and these clouds eclipse R Mon (as they orbit about it) casting shadows onto the foreground nebula.


20in RC Optical Systems telescope Operating at f/8.4
Paramount ME Robotic Telescope Mount
SBIG ST10XME CCD camera with color filter wheel

L R G B color production was used to create this image.

Luminance = 75 minutes binned 1x1
Red = 20 minutes binned 2x2
Green = 20 minutes binned 2x2
Blue = 20 minutes binned 2x2

  • Poor seeing.
  • DDP and deconvolution was used on this data.
  • Minimum credit line: Carole Westphal/Adam Block/NOAO/ AURA/NSF

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    Updated: 12/27/2003