Author Topic: Crater matching - Apollo 15 v LROC  (Read 12931 times)

Geoff

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Re: Crater matching - Apollo 15 v LROC
« Reply #15 on: November 08, 2010, 02:15:24 pm »
Good detective work Jules  :)

jules

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Re: Crater matching - Apollo 15 v LROC
« Reply #16 on: November 08, 2010, 02:46:38 pm »
We need another case to solve now.... ::) ;D

Tom128

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Re: Crater matching - Apollo 15 v LROC
« Reply #17 on: November 08, 2010, 03:30:50 pm »
Hi Jules,

Great work finding the Apollo 15 crater on the LRO photo strip.  Wow, that boulder is big!  My head was beginning to explode trying to piece things together. Glad you finished it off.

Tom

Tom128

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Re: Crater matching - Apollo 15 v LROC
« Reply #18 on: November 09, 2010, 02:56:15 am »
Thought I would post two cropped versions showing our newly identified crater, thanks to Jules expert use of the LROC image search, side by side.  Here is the link to the LROC version and below the link to the Apollo 15 version.  We can still perform some boulder and crater matching looking for change as we wait for a better LRO photo strip of the entire crater. Then we can really get down to business and do some crater surveying of the interior looking for change.  The first thee people to identify a new crater or boulder since 1971 gets written up on the next IOTW.  Please post your discoveries before Sunday the 21st  :D
                                                                                                                       

                                                                                                                                                                     Apollo 15 version   
   
   

                                                                                                 
« Last Edit: November 09, 2010, 03:06:59 am by Tom128 »

astrostu

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Re: Crater matching - Apollo 15 v LROC
« Reply #19 on: November 09, 2010, 07:59:15 am »
There we go, that looks more like it. :)  Sorry to spoil your fun before.

After looking a bit, I agree with Jules that there is not another NAC image yet available to better show this crater.  I also don't think you're going to spot any new craters from one versus the other (I looked, and the Apollo resolution just doesn't seem to be good enough).  I also didn't see any evidence of large blocks having moved, but I didn't do an exhaustive search, I just looked for about a dozen examples with good shadows.
« Last Edit: November 09, 2010, 08:14:51 am by astrostu »

jules

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Re: Crater matching - Apollo 15 v LROC
« Reply #20 on: November 09, 2010, 12:31:09 pm »
Lined them up in Photoshop so I could blink one image off and on to look for differences. Sad to say I couldn't find any.
All good practice though! ;D

Tom128

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Re: Crater matching - Apollo 15 v LROC
« Reply #21 on: November 09, 2010, 03:49:27 pm »
Let's hope a better LROC photo view surfaces or perhaps we can request one that will cover the entire crater. The cropped view of the Apollo 15 shows only the shadow part of the crater interior while the other portion is well lit showing numerous boulder etc.  I am really interested in comparing the center area again. 

MZ Forum claims first survey rights  8)
« Last Edit: November 09, 2010, 04:09:24 pm by Tom128 »

jules

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Re: Crater matching - Apollo 15 v LROC
« Reply #22 on: November 09, 2010, 04:51:58 pm »
I requested the other half of the crater via the targeting tool only to receive the message that it had already been requested. Somebody else is on to it!!! ;)

Tom128

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Re: Crater matching - Apollo 15 v LROC
« Reply #23 on: November 10, 2010, 05:13:10 am »
Matching boulders is tough business, especially on the Apollo 15 version but after a while it is surprising how much detail you can pull out of the photograph.

I think I may have found some evidence of erosion on the crater wall that has exposed a boulder not previously shown in the Apollo 15 photograph.  My thought is that it should have shown up fairly well as it is large and reflective looking. Marked the exposed boulder with yellow arrow.  You can see what may possibly be the outline of the now exposed boulder covered with regolith in the Apollo 15 version, though it seems to be positioned a little too far below the visible boulder above it.

   
 
« Last Edit: November 10, 2010, 06:32:07 am by Tom128 »

jules

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Re: Crater matching - Apollo 15 v LROC
« Reply #24 on: November 10, 2010, 09:53:27 pm »
Here's an enhanced version. The boulder has a shadow so I'm guessing it was the same then as it is now.

Tom128

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Re: Crater matching - Apollo 15 v LROC
« Reply #25 on: November 10, 2010, 11:12:12 pm »
Hi Jules,

Thanks for making the enhancement of the boulders.

Interesting that the large shadow to its right does not appear to touch the boulder while it looks like the shadows all touch the others.  There is a darker line to its left but that wouldn't fit in.  Guess I need more than this one suspect boulder that appears to be in poor lighting down from the crater's rim to indicate erosion.  However, the suspect boulder appears to be larger than the visible one above it and the lighting in the photograph seems sufficient to show this boulder as it appears to have a large reflective surface. If you look at the crater surface to its left there are similar looking form like shadow but no visible boulders of this size- much smaller.

As you can tell, I am having a lot of fun working on this.
« Last Edit: November 13, 2010, 12:50:21 am by Tom128 »

jules

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Re: Crater matching - Apollo 15 v LROC
« Reply #26 on: November 11, 2010, 01:00:55 pm »
The resolution of the Apollo 15 pic just isn't good enough to look at boulders that small. It would be good to have the other half of the LROC image though to look for larger scale changes.

IreneAnt

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Re: Crater matching - Apollo 15 v LROC
« Reply #27 on: November 12, 2010, 08:35:47 pm »
This is a really amazing discussion!! I would recommend though, that it be split off into it's own thread. I am worried about it getting lost in the Boulder Repellent thread...

jules

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Re: Crater matching - Apollo 15 v LROC
« Reply #28 on: November 12, 2010, 09:22:46 pm »
I'm on the case!
EDIT - Topic split!
« Last Edit: November 12, 2010, 09:28:40 pm by jules »

Tom128

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Re: Crater matching - Apollo 15 v LROC
« Reply #29 on: November 15, 2010, 02:32:45 am »
I have been looking closely at the Isidorus D crater from the Apollo 16 photograph looking for change.  Here is the link to the original post.  Had to flip the Apollo 16 pic horizontally to get The LROC photo strip oriented correctly when facing the landslides. 

The yellow arrow points to the landslide that may have changed as it appears more rounded with possibly only one landslide thread moving out on the left side.

 


Here is the LROC version with the arrow pointing to the same area. I marked with a solid line where the other landslide threads may have moved past the rounded end.  Notice how true to form the larger landslide is keeping on both the Apollo 16 and LROC versions, showing a square looking appearance at the end of the slide.  The item of interest, in the LROC version, appears much less rounded and perhaps more of a square looking end which may be indicating the threads moved out from the rounded part since Apollo 16 flew by.  This may be an area to look at more closely.




« Last Edit: November 15, 2010, 02:50:11 am by Tom128 »