Star Cluster with Nebulosity (?) in Canis Major

Uploaded 1/08/02

Only a small handful of star clusters in the sky imress me enough to photograph them, and the cluster around Tau Canis Majoris is one of them. The central star, easily visible to the naked eye at a magnitude of 4.4, is the main gem in a sprinkling of diamonds on black velvet. The cluster is brilliant, at magnitude 3.8 and is a perfect 8 arcminutes in size. The spectral class of Tau is Type O, and the rest of the cluster has a bluish cast as well. Interestingly enough, this cluster is also plotted in Megastar with nebulosity, however none shows in my image. Guide 7 does not mention the nebulosity either. It is possible it may be only visible on a deep schmidt exposure.

Processing: Calibration with dark, stacking with Maxim DL, RL deconvolution in AIP, LRGB in Photoshop.

Instrument:  12.5" f/5 Home made Newtonian
Platform:  Astrophysics 1200 QMD
CCD Camera:  SBIG ST7E w/Enhanced Cooling
Exposure:  LRGB = 30:10:10:16 (RGB Binned 2x2)
Filters:  RGB Tricolor
Location:  Payson, Arizona
Elevation:  5150 ft.
Sky:  Seeing FMHW = 3.0 arcsec, Transparency 8/10
Outside Temperature:  -5 C
CCD Temperature:  -35 C
Processing:  Maxim DL, Photoshop, AIP4WIN, PW Pro.




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