Abell 12

Planetary Nebula in Orion

Uploaded 1/12/01

This object is seldom photographed because of its extreme faintness and proximity to 4.4 magnitude mu Orionis. This spectral class A2 star is so close, that film images nearly always hide the planetaries image completely, and George Abell only discovered it on the Poss plates by noting a small portion of it protruding from the stars overexposed glow. The planetary itself is listed as 14th magnitude, but a sizable 37 arcseconds in diameter. The 20th magnitude central star is not seen here. Just above mu, the bright star in the center of the image is an orange "object". This is classified as a non star in the Guide Star Catalog. This CCD image not only records the nebula completely separated from the star, but its green color with a red rim.

This image was taken by combining 21 ten second exposures in a red luminance, and 5 each 10s RGB.

Instrument:  12.5" f/5 Home made Newtonian
Platform:  Astrophysics 1200 QMD
CCD Camera:  SBIG ST7E w/Enhanced Cooling
Exposure:  RRGB = 3.5m:50s:50s:50s 
Filters:  RGB Tricolor
Location:  Payson, Arizona
Elevation:  5150 ft.
Sky:  Seeing FMHW = 2.5 arcsec, Transparency 8/10
Outside Temperature:  0 C
CCD Temperature:  -25 C
Processing:  Maxim DL, Photoshop, AIP4WIN




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