Author Topic: Crater matching - Apollo 15 v LROC  (Read 12524 times)

Tom128

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Re: Crater matching - Apollo 15 v LROC
« Reply #30 on: November 18, 2010, 05:30:33 pm »
I have been spending some time looking for change in this small crater near the rim of Daguerre crater that is shown in Apollo 16 high resolution photograph AS16-4511 (P).  Click here to read the original post. 

Below is the LROC  and Apollo 16 photographs of the crater.








The photographs are inverted, so I circled the two boulders on the rim  for orientation.  Here are a couple of candidates for possible change between the two pics.



The yellow arrow points to a boulder in the LROC version that does not appear to be present in the Apollo 16 version but does appear to be of sufficient size to have shown up.

What does seem a high probability for change is the ejecta covering differences between the two photographs.  In the Apollo 16 version the ejecta appears fairly uniform which I roughly marked in blue. You can also see some darker areas that match to the LROC version.

The change in my view is shown in the LROC version that has areas, some of which I marked in yellow, that show no to very little ejecta covering. Other areas are fairly light and increase in intensity, marked in blue.  Comparing the ejecta around the crater wall, there does appear to be a change in albedo that should be showing up in the Apollo 16 pic.  My thought is that some type of erosion/weathering may explain the absence of ejecta or has made the ejecta coat markedly thinner in areas in the LROC version.   




 
« Last Edit: November 18, 2010, 07:08:41 pm by Tom128 »

jules

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Re: Crater matching - Apollo 15 v LROC
« Reply #31 on: November 18, 2010, 10:12:00 pm »
Hmmm... Here's the 2 images cropped to the same size. I superimposed one on top of the other to try to line them up but it's clear that they were taken from very different angles under different illumination.  I've also tweaked the brightness of the area in question on the Apollo pic. You can see where the boulder should be but again I don't think the Apollo pic's resolution is good enough to spot differences.  :(

This is fun though and I hope we do come across an Apollo (or other orbiter) photo that we can use to compare!
« Last Edit: November 19, 2010, 10:14:24 am by jules »

Tom128

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Re: Crater matching - Apollo 15 v LROC
« Reply #32 on: November 29, 2010, 10:38:51 pm »
I am finally going to finish off my prospective changes for this crater. For a while now these last two possible change items have been nagging on me.  I have been trying to reconcile the differences in the center ring between the two photographs. Some is simply albedo change and perhaps a slightly different angle aspect between the two spacecrafts. However, there does seem to be some alteration (marked in red).

The other puzzling piece for me is the angle differences in the rock slides in the two pics. I put a red line on them to to show the change. As discussed before, the yellow marked items are areas (possible change) that have little to no ejecta covering and the blue shows where there still remains a fairly heavy covering. The last item is the arrow pointing to the boulder that does not appear to be present in the Apollo 16 version.

Here is the LROC photo strip of the crater again.  So now, Jules and I have completed this fun speculation on possible changes  :)



 
« Last Edit: December 22, 2010, 06:04:05 pm by Tom128 »

Tom128

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Re: Crater matching - Apollo 15 v LROC
« Reply #33 on: April 30, 2011, 05:50:55 am »
The ACT-REACT tool gives us a excellent platform to compare Apollo mission Panoramic camera photographs with for possible changes.  Here is the link to the Lunar Planetary Institute "Apollo Image Atlas

Panoramic Image Catalog"  http://www.lpi.usra.edu/resources/apollo/catalog/pan/

Below are links to two views of the same crater, Apollo 15 and later by LROC using the ACT-REACT tool.  You can download the Apollo pics to enlarge them with your photo viewer and then compare with the ACT-REACT version. Any changes as in new craters, boulder placement etc., within the resolution limitations of Apollo will show up easily with the photo strips.  The nice thing with the ACT-REACT tool is you can enter the lat and long of the Apollo photographs and then find the formation using the WAC mosaic. Scroll in to find interesting features.  The new tool cuts search time down tremendously. I'll let you know when I find a very obvious change  8)  I have been searching the crater below and thus far things look pretty much the same.  Plan to move on to another photograph as there is more than enough to keep one busy.

http://www.lpi.usra.edu/resources/apollo/frame/?AS15-P-9045


http://target.lroc.asu.edu/da/qmap.html?mv=eqc&mcx=3300901.54666&mcy=-276600.12818&mz=10&ml=FTFB00TT
« Last Edit: April 30, 2011, 06:18:57 pm by Tom128 »