May 10, 2005

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Theo as You've Never See It


Image Credit: Mike Wirths

Theo as You've Never See It

Theophilus is one of the lunar superstars - a magnificent crater that attracts the attention of observers and imagers. It is a complex crater like Copernicus, but slightly bigger (100 vs 93 km). Its terraces are not as well formed or as well preserved as those in Copernicus, but its central mountains are much bigger. The reason is totally unknown. In general, central peaks are larger in diameter and height in larger craters, but there is great variability. The peaks of the same size crater Cyrillus (bottom left) are smaller and more rounded, but who knows how much of that may be related to being pummelled by Theo’s ejecta. The flat, relatively smooth floor in Theophilus probably includes target rocks melted by the energy of the impact that were ejected nearly vertically. That they splashed back down is obvious from Apollo 16 images that reveal melt ponds caught in hollows immediately outside the crater and on terraces inside it.

Chuck Wood

Technical Details:
April 15, 2005. 18" dob + Atik webcam + 5X's barlow + Baader IR passband filter.

Yesterday's LPOD: NOT the Source of Lunar Nomenclature

Tomorrow's LPOD: Imperial Image

Author & Editor:
Charles A. Wood



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