Sharpless 2-188

Emission Nebula in Cassiopeia

Uploaded 1/25/02

Located in central Cassiopeia, this clearly intriguing object has been classed as both an emission nebula and planetary nebula. It is quite large at 9 arcmins, and quite invisible visually, even with nebular filters and a large scope. The central star is very dim, and is the tiny bluish object just to the upper left of the bright orange star in the middle. It is 17.4 magnitude. It does not appear central in the nebula. Centering this faint wisp required matching the star patterns in Megastar on the screen simultaneously with the focus mode running to frame the subject. even in 10 second exposures binned 3x3, nary a trace of nebulosity was seen. The Red luminance did the trick however, and a deep series of subframes brought this object to view.

Seeing was atrocious this night! Stars were originally 5 arcseconds or more across, giant bloat balls for images. But with a fairly high signal to noise, the image was greatly improved with the RL deconvolution in AIP to more acceptable levels.

Instrument:  12.5" f/5 Home made Newtonian
Platform:  Astrophysics 1200 QMD
CCD Camera:  SBIG ST7E w/Enhanced Cooling
Exposure:  RRGB = 60:20:20:36 (RGB Binned 2x2)
Filters:  RGB Tricolor
Location:  Payson, Arizona
Elevation:  5150 ft.
Sky:  Seeing FMHW = 5 arcsec, Transparency 8/10
Outside Temperature:  0 C
CCD Temperature:  -35 C
Processing:  Maxim DL, Photoshop, AIP4WIN, PW Pro.




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