Thor's Helmet: So named for its resemblance to the mythical Norse god's helmet, this is a gas cloud being shaped by the stellar winds from a very large, very hot and very old star at the center of the "helmet," called a "Wolf-Rayet" star. These stars are about 20 times the mass of our Sun, or more, and they are losing mass at very high rates, possibly as a foreshadowing of going supernova. The color of the nebula is caused by ionization of the gas by the hot Wolf-Rayet star. Thor's Helmet is about 15,000 light years away, and about 30 light years across.
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Technical Information:
(HaL)(HaR)GB: 150:180:150:150:150; Luminance layer consists of a blending of ten 15-minute images taken through an Ha filter and twelve 15-minute images taken through a clear filter; red channel consists of a blending of the same Ha data used in the luminance layer, and ten 15-minute images taken through a red filter; the green and blue channels consist of ten 15-minute images each.
Equipment: Takahashi FSQ106, SBIG STL11000 (with Astrodon Generation 1 filters), on a Bisque Paramount ME German Equatorial Mount.
Image Acquisition/Camera Control:MaximDL, working in concert with TheSky v6, all controlled with ACP Observatory Control software.
Processing: All images calibrated (darks and dawn flats), aligned, sigma reject performed, and combined in CCDStack. Luminance layer(s) mildly deconvolved in CCDStack. Color combine in CCDStack. Finish work was done in Photoshop CS5.
Location: Data acquired remotely from Fair Dinkum Skies, near Moorook, South Australia.
Date: Images taken in March 2011. Image posted April 2, 2011.
CCD Chip temperature: Varied from -5C to -15C
Copyright 2011 Mark de Regt
