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46P/Wirtanen on 12-11-18 | by HypatiaPhoto
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46P/Wirtanen on 12-11-18

Comet Wirtanen approaching perihelion on 12-11. The comet is now naked-eye visible. It's possible to sight it clearly as a faint-fuzzy patch even under a moonlit sky. It stands out ever clearer using averted vision. No visible color yet, though it does show up strongly on long-exposure photographs. The blue-green color is due to strong emission of Cyanogen [ (CN)₂ ] and diatomic Carbon. (C₂)


My previous image of comet Wirtanen was less than ideal as I was not prepared to shoot in the cold. The weather has been quite unpredictable lately, so I decided to photograph the comet again, this time using a faster lens at a narrower focal length. Good thing I decided to, as it snowed the night after. Plus, it was an opportunity to play with the tripod I got for Christmas early, naughty me. :)


Gear Used:

Camera - Canon EOS 350D

Lens - Canon EF 75-300mm

Tripod - Pedco Ultrapod II


Acquisition Details:

91x6" sub exposures

9.1 minutes total integration time





Adobe Camera Raw


Adobe Photoshop CS5.1



Processing Details:

Noise reduction, lens correction and a linear tone curve applied in Adobe Camera Raw. Images converted to lossless TIF format and then stacked in Deep Sky Stacker using Stars + Comet Stacking, Kappa-Sigma Clipping and 2x Drizzle. Final stack sent to Photoshop for gradient removal, color correction and a nonlinear stretch. HLVG plugin was applied on "weak" settings to remove the green cast on some stars, comet was masked so green reduction was less in that area. Image finally had a saturation boost applied and was cropped slightly.

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Uploaded on December 15, 2018