SH2-132 - The "Dumbledore Nebula" Object Description:
Sharpless 2-132 is a very faint emission type nebula on the Cepheus/Lacerta border. It lies at a degree southeast of Epsilon Cep, and has a size of about 40 arc minutes. It's easy to locate because of its proximity to the distinctive triangle of stars formed by delta, epsilon and zeta Cephei (delta Cep is the prototypical Cepheid variable). From northwest to southeast, zeta, epsilon and Sh2-132 form an almost straight line. The distance between zeta and epsilon is 1.25 degrees, and between epsilon and the nebula is 1.0 degree. Helping to locate the nebula is a very wide optical double about 1/4 degree due west of it.
Sh2-132 lies in the field of the Cepheus OB1 association. If it is related to Cep OB1, whose distance is given as 10,000 to 12,000 light-years, then it would be located well out in the Perseus arm of our Galaxy, and be more than 250 light-years in extent.
Date Taken:
- 7/24/2007 through 8/12/2007
Equipment Used:
- TMB 203 F/7
- SBIG STL-6303
- Paramount ME
- Optec 3" rotator
- Starlight Instrument's Digital Feather Touch Focuser, (with electronic focusing)
- Astrodon narrowband filters
Exposures:
Main Nebula:
- Ha: 17x30 minutes (8.5 hours)
- OIII: 19 x 30 minutes (9.5 hours)
- SII: 22 x 30 minutes (11 hours)
Totaling 29 hours
Stars:
- R: 8 x 5 minutes
- G: 8 x 5 minutes
- B: 11 x 5 minutes
Processing:
CCDStack:
For each data set:
1) Calibration with darks, flats, and bias frames
2) Bloom rejection
3) Impute (minor) bloomed pixels
4) Image registration
5) Normalization (Auto)
6) Data rejection (Poisson sigma)
7) Mean combine
8) Hot/Cold Pixel rejection
9) Impute hot/cold pixels
10) Deconvolution, Positive Constraint, 25 iterations
Photoshop CS2:
For each data set:
1) Overall “contrast curve”
2) Noel Carboni’s Photoshop action for “local contrast enhancement”
3) Noise removal (NeatImage)
4) Color combine, in the two palettes mentioned above
5) Color adjustments through levels, curves, and saturation adjustment layers
6) Shadow-highlight to bring up the background data
7) Layered in RGB-based star data
8) Sharpening |
