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Apollo Sites from LRO
Phil Stooke
post Sep 12 2016, 08:07 PM
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Follow-up on the Apollo 12 - possible - Lunar Module Ascent Stage impact. Looking at more images of the area I have found what may be the impact site, showing up as a gouge or linear depression, possibly with a crater at the end. I attach two images, each a composite of several, to tell the story.

A is a regional map showing the Apollo 12 landing site, LM impact target and predicted impact area.
B is a close-up showing the predicted impact area and two features, the area of dark streaks described earlier, and the new feature which may be the impact site.
C is a comparison of twi LROC NAC images showing the impact feature, and a composite of the two which reduces the effects of shadowing and emphasizes albedo markings. The impact site is dark.
D is the area of dark streaks.
E-H zoom in on the impact feature to locate it unambiguously.

(These are set up as illustrations for a future book.)

Phil

Attached Image


Attached Image


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john_s
post Sep 13 2016, 02:55 AM
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Nice work! It looks quite convincing to me. I'm intrigued by your use of the images with different lighting to separate albedo and topography- is the merged image simply a linear combination of the two, or something fancier?

John
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Phil Stooke
post Sep 13 2016, 12:12 PM
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Thanks, John. The shadow-cancelling method is surprisingly easy and effective. It is just a linear addition of two images with approximately opposite lighting. Shadows and highlights cancel each other out, greatly reducing the visibility of topography and clarifying the albedo markings. I have used it with what is sometimes referred to as 'jaw-dropping' effectiveness on Lunokhod and Apollo astronaut tracks, where individual images did not reveal them clearly.

Phil


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Phil Stooke
post Sep 13 2016, 07:32 PM
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Another example of the shadow-cancelling method. This is Apollo 14, EVA 1 near the ALSEP. Two individual NAC images plus a merged version. The topography does not cancel completely because they are stretched differently, but look at how the tracks pop out!

Phil

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Phil Stooke
post Nov 2 2016, 04:46 PM
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Allow me to introduce to you.... the Apollo 14 LM Ascent Stage impact site!

Attached Image



This is almost exactly at the tracking location. Its latitude and longitude in Quickmap coordinates are 3.4202 S, 19.6368 W (340.3632 E). My hero, Ewen Whitaker, who sadly just died aged 94 a couple of weeks ago, tried to locate the impact site and suggested it was at the location of an unusual dark spot in an Apollo 16 Metric Camera image (frame 2508). He had just observed that Ranger and other artificial impacts tended to look dark from orbit, so it was a reasonable suggestion. But it was not quite in the right place. In this case he was mistaken. This spot shows features very similar to the Apollo 12 LM Ascent Stage impact, illustrated above on this page. I will be presenting this at LPSC.


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Ian R
post Nov 3 2016, 10:31 AM
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Nice discovery Phil, and sad news about Ewen Whitaker.

How is the second edition of your Lunar Atlas coming along?


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Phil Stooke
post Nov 3 2016, 12:18 PM
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Thanks. The book is coming along pretty well. It went fast during my half-year sabbatical, January to June. Now I'm back teaching it's slowed down a lot. But I hope to finish the revision of the first volume (ending at Luna 24) by December next year, and then get into a Volume 2 which is everything after Luna 24 up to the present. It is greatly improved by the use of LRO data and corrections to some errors in Vol. 1.

Phil


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Phil Stooke
post Yesterday, 06:23 PM
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Another Apollo LM ascent stage? I think so. I believe this is the Apollo 15 ascent stage impact site. Later I will post something showing exactly where this is. The images are enlarged from the original scale.

As for Apollos 12 and 14, the impact appears to be a linear gouge rather than a crater, with faint ejecta extending in a downrange fan.

LROC image numbers are in the file names, if you save the images.

Phil

Best image, south lighting, 0.5 m/pixel (original scale):

Attached Image


Composite of two images with opposite lighting to emphasize albedo markings, about 1 m/pixel original scales:

Attached Image



Image with morning lighting showing faint dark rays extending to the west.

Attached Image


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James Fincannon
post Yesterday, 07:13 PM
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[quote name='Phil Stooke' date='Feb 21 2017, 07:23 PM' post='234703']
Another Apollo LM ascent stage? I think so. I believe this is the Apollo 15 ascent stage impact site. Later I will post something showing exactly where this is. The images are enlarged from the original scale.



I don't know how you do this! I can't discern the difference between this and any other old impactor. I guess it just takes a trained eye.

By the way, any opinion of this blocky thing in Paracelsus C others have found? Simplified link to QuickMap.

http://bit.ly/2ljHDYT

Maybe it is just a blocky thing, but I would like it if there were a lot more blocky things in the area which there are not.




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Phil Stooke
post Yesterday, 08:43 PM
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That has to be one of the most puzzling things I have ever seen on the Moon. I looked at it with morning and afternoon illumination, and with the Sun nearly overhead. The shadows on the southern object hardly seem to make sense at all, and the northern one is not much better. No idea what it is. Some 3D modelling from stereo images would be useful... I see some of that has been done already, but I am not sure the shadows work with the suggested shape. I will keep thinking about it.

Phil

EDIT: here are the only 4 LRO images. There are Apollo 15 images as well.

Attached Image




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Phil Stooke
post Yesterday, 11:27 PM
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OK... got it all figured out now. I will post something tomorrow.

Phil


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