December 10, 2016

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A Colorful Helmet

Originally published January 29, 2007

Image by Zac Pujic

Yesterday’s high Sun view of the Helmet ended with a plea for a high res amateur view, and here it is, in color! The extreme processing to saturate the subtle colors created dark artifacts within the bright mountain (Herigonius Eta) and a few other places. Zac’s image shows that the yellowish-gold Helmet is sharply bounded from the surrounding purple maria - the maria has lapped up around the gently sloping Helmet, creating the smooth boundaries. Interestingly, although the hilly stuff at bottom right has the same saturated color as The Helmet, in more detailed spectral studies it is not the same, so is probably not volcanic terrain. It is interesting that the peak Eta has the same spectral colors as the Gruithuisen domes - Eta must also be an extrusion of pasty, silica-rich lava. All of the red spots - see yesterday’s LPOD - are in the western half of the visible hemisphere of the Moon, within the putative Gargantuan impact basin. Were the red spots made by eruptions of this unusual magma onto the floor of Gargantuan? And are they only exposed where the more recent mare basalts are thin?

Chuck Wood

Technical Details:
15 August 2005. 32 cm f/5.75 Newtonian @ f/28 + Phillips ToUcam Pro webcam. Frames from avi stacked using Registax. Saturated colour produced using Photoshop. Unlike yesterday, this image has north up.

Related Links:
Zac’s website

Yesterday's LPOD: Herigonius Pi & Eta

Tomorrow's LPOD: Upside Down Twins


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