WR-134 and its Ring Nebula in Cygnus (HOO Bicolor)

WR-134 is a Wolf Rayet star located in Cygnus. The star itself, located about 6000 light years from Earth, is surrounded by a Oxygen-dominated nebula that is being blown around by radiation and winds from the WR star itself. The star itself is about 5 times the radius of our sun and was one of the first three stars observed in Cygnus to have intense emission lines rather than continuous or absorption lines. This class of stars is now known as Wolf-Rayet stars.

 

This image is a HOO Bicolor image totaling about 34.7 hours of exposure time taken over 7 nights.

 

This image will eventually be mosaic'd with the Crescent Nebula, which I am current halfway done gathering data for.

 

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Equipment:

 

- Scope: AstroTech AT65EDQ Quad APO

- Mount: Rowan Belt Modded Orion Sirius EQ-G

- Imaging Camera: ZWO ASI1600mm-Pro

- Guidescope: QHY MiniGuideScope

- Guide Cam: QHY5L-II Mono

 

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Software:

 

- EQMOD/StellariumScope for mount control

- APT for image capture and platesolving

- PHD2 for guiding

- PixInsight for Processing

 

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Acquisition:

 

- Location: Sugar Land, TX

- Gain: 200; Offset: 50; Camera @ -10C

- 195 x 300" Ha - Chroma 5nm

- 221 x 300" OIII - Chroma 3nm

- 30 flats, flat darks, and darks (from library) per session

- Nights: 7/30/20, 8/3/20, 8/4/20, 8/6/20, 8/7/20, 8/10/20, 8/11/20

- Total Integration Time: 34.7 Hours

 

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Processing (Apply to each Ha and OIII master):

 

- ImageIntegration

- DrizzleIntegration

- DynamicCrop to get rid of edges

- DBE

- Deconvolution

- Linear noise reduction via EZDenoise Script

- HistogramTransformation for Stretch

- HistogramTransformation for contrast

- CurvesTransformation to bring out nebulosity

- DarkStructureEnhance script (Ha only)

 

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Combining Ha and OIII Masters via the following Pixelmath Combination:

 

- R: iif(ha>.15,ha,(ha*.8)+(oiii*.2))

- G: iif(ha>0.5,1-(1-oiii)*(1-(ha-0.5)),oiii*(ha+0.5))

- B: iif(oiii>.1,oiii,(ha*.3)+(oiii*.2))

 

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Further Processing:

 

- Invert -> SCNR Green -> Invert back to remove magenta cast

- Export to Photoshop for slight color tweaking

- Bring back to PI for curves on hue and contrast

- Pushed nebulosity by creating a starless version of the image and then using the following Pixelmath Expression:

 

- 1- (1-$T)*(1-$T)

 

- Recombined this enhanced nebulosity version with the original version via the following Pixelmath Expression:

 

- F=0.4; (1- (1-$T)*(1-starless)*F)+($T*~F)

 

- Additional CurvesTransformation for contrast

- LocalHistogramEqualization on ring nebula with RangeMask

- Create star mask via Starnet++, binarize and convolute star mask

- MorphologicalTransformation to reduce star size

- CurvesTransformation to shift hue to red from rusty red

- Extract blue channel and apply ask a mask and use CurvesTransformation to emphasize the OIII emissions and balance some color

- Nonlinear noise reduction via ACDNR and luminance mask

- Final Export

 

 

Done