Difference between revisions of "June 27, 2004"

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<p class="story" align="center"><b>An Older Tycho</b></p>
 
<p class="story" align="center"><b>An Older Tycho</b></p>
<p class="story" align="left">Have you ever set up your telescope when the Moon is about 9 days old and scanning the terminator said, "Must be a great libration, Tycho is pretty far south tonight"? I have, and then I realized that I've been fooled once again by Tycho's look-alike, Moretus. Like the pair [[June_26,_2004|Eratosthenes]] and [[February_4,_2004|Copernicus]], Moretus is the older and over-shadowed lesser twin of one of the best known craters on the Moon. But Moretus is worth a second look for it is another classic example of a complex lunar crater. Its 114 km diameter rim steps down via one large scarp and a jumble of terraces to a flat floor 3.95 km below the rim crest. John's photo shows parallel banding in the wall - traces of the original terraces. The floor is mostly smooth (impact melt?) and this Lunar Orbiter IV [[iv_130_h2.jpg|image]]  reveals a narrow rille that seems unusual for impact melt. There is also a large central peak and some low hills, especially to the west. Orbiter images also show subdued secondary craters to the northwest, and a search at full Moon shows that Moretus is invisible - no rays nor rim brightness remain. The lack of rays is consistent with the number of superposed impact craters on Moretus' floor - it is an older crater of [[February_23,_2004|Eratosthenian]] age.  </p>
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<p class="story" align="left">Have you ever set up your telescope when the Moon is about 9 days old and scanning the terminator said, "Must be a great libration, Tycho is pretty far south tonight"? I have, and then I realized that I've been fooled once again by Tycho's look-alike, Moretus. Like the pair [[June_26,_2004|Eratosthenes]] and [[February_4,_2004|Copernicus]], Moretus is the older and over-shadowed lesser twin of one of the best known craters on the Moon. But Moretus is worth a second look for it is another classic example of a complex lunar crater. Its 114 km diameter rim steps down via one large scarp and a jumble of terraces to a flat floor 3.95 km below the rim crest. John's photo shows parallel banding in the wall - traces of the original terraces. The floor is mostly smooth (impact melt?) and this Lunar Orbiter IV [http://www.lpi.usra.edu/research/lunar_orbiter/images/img/iv_130_h2.jpg image]  reveals a narrow rille that seems unusual for impact melt. There is also a large central peak and some low hills, especially to the west. Orbiter images also show subdued secondary craters to the northwest, and a search at full Moon shows that Moretus is invisible - no rays nor rim brightness remain. The lack of rays is consistent with the number of superposed impact craters on Moretus' floor - it is an older crater of [[February_23,_2004|Eratosthenian]] age.  </p>
 
<blockquote>
 
<blockquote>
 
<p align="right" class="story">&#8212; [mailto:tychocrater@yahoo.com Chuck Wood]</p></blockquote>
 
<p align="right" class="story">&#8212; [mailto:tychocrater@yahoo.com Chuck Wood]</p></blockquote>
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<p class="story"><b>Related Links:</b><br>
 
<p class="story"><b>Related Links:</b><br>
 
[http://www.jsussenbach.nl/ Sussenbach's Digital Astroimaging Site]<br>
 
[http://www.jsussenbach.nl/ Sussenbach's Digital Astroimaging Site]<br>
[[iv_118_h2.jpg|Lunar Orbiter IV View]]  
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[http://www.lpi.usra.edu/research/lunar_orbiter/images/img/iv_118_h2.jpg Lunar Orbiter IV View]  
 
</p>
 
</p>
 
<p><b>Yesterday's LPOD:</b> [[June 26, 2004|An Older Copernicus]] </p>
 
<p><b>Yesterday's LPOD:</b> [[June 26, 2004|An Older Copernicus]] </p>

Latest revision as of 22:39, 8 February 2015

An Older Tycho

LPOD-2004-06-27.jpeg

Image Credit: John Sussenbach

An Older Tycho

Have you ever set up your telescope when the Moon is about 9 days old and scanning the terminator said, "Must be a great libration, Tycho is pretty far south tonight"? I have, and then I realized that I've been fooled once again by Tycho's look-alike, Moretus. Like the pair Eratosthenes and Copernicus, Moretus is the older and over-shadowed lesser twin of one of the best known craters on the Moon. But Moretus is worth a second look for it is another classic example of a complex lunar crater. Its 114 km diameter rim steps down via one large scarp and a jumble of terraces to a flat floor 3.95 km below the rim crest. John's photo shows parallel banding in the wall - traces of the original terraces. The floor is mostly smooth (impact melt?) and this Lunar Orbiter IV image reveals a narrow rille that seems unusual for impact melt. There is also a large central peak and some low hills, especially to the west. Orbiter images also show subdued secondary craters to the northwest, and a search at full Moon shows that Moretus is invisible - no rays nor rim brightness remain. The lack of rays is consistent with the number of superposed impact craters on Moretus' floor - it is an older crater of Eratosthenian age.

Chuck Wood

Technical Details:
April 11, 2003. C11 and 2 x Barlow plus Toucam Pro.

Related Links:
Sussenbach's Digital Astroimaging Site
Lunar Orbiter IV View

Yesterday's LPOD: An Older Copernicus

Tomorrow's LPOD: LACs and More!


Author & Editor:
Charles A. Wood

 


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