larrytOMC200
sage
Reged: 07/05/07
Posts: 312
Loc: New Zealand
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Hello all,
I was out on the night of the 24th August (Dunedin time) and caught sunrise around the area of Mare Humorum. Gassendi was nicely placed to view the small floor details that can be caught with modest aprtures such as I use. The mare itself is approx 230 miles in diameter and is dated by the VMA as being of Nectarian age (3.92 - 3.85 billion years ago). The low sun angle shows the final moment in time where the last issues of the lavas filling the floor of Mare Humorum finally solidified leaving the 'footprint in time' showing the direction of the flows that filled the basin.
The weight of the lavas seem to have caused the crust to fault, concentic faults running along the margins of the Mare can be seen.
Image obtained using my OMC200 and opticstar 122 ccd with a star diagonal in place.
Keep well. Larry
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Jaycin
Carpal Tunnel
Reged: 07/09/06
Posts: 2146
Loc: Oregon, USA
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Great shot, Larry! 
I can clearly see the rille system in Gassendi which has always reminded me of a highway network. Also, the concentric faults that outline the perimeter of the Mare are something I've not noticed while visually observing. Thanks for sharing! 
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Jason
Zhumell 8" Dobsonian
60mm Meade Telestar
Sketching the Cosmos
Messier countdown: 102 down, 8 to go! 
Salem, Oregon
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Carol L
Reged: 07/05/04
Posts: 6968
Loc: Tomahawk, WI 45N//89W
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Thanks Larry, the rimae of the area really 'pop' under this light angle. I see you caught Rimae Ramsden and Rima Agatharchides, too.
Speaking of favorable light angles, I see another Agatharchides rille that's not in any of my resources. Your image definitely shows an 'X'.. any chance of posting a higher resolution crop?
In this LO image you can see where the extra rille originates, but it must need a very low light angle to be seen (let alone imaged). Great catch!
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Carol Lakomiak, Tomahawk WI
Writing Sky at Night magazine's astrosketch page since June 2009
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larrytOMC200
sage
Reged: 07/05/07
Posts: 312
Loc: New Zealand
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Hi Jason and Carol,
Thanks for the comments. Carol, I hope this is the area you were on about. I cropped part of the image and enlarged it in registax. Keep well. Larry
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Stephen65
scholastic sledgehammer
Reged: 04/14/07
Posts: 941
Loc: Melbourne, Australia
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I must have been out at almost the same time as you Larry as I got a very similar shot of Gassendi that night:
PS: FLT132 + TV 3x barlow + SPC900
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Megrez 90
FLT 132
Mewlon 250
Lots of XWs, an Ethos, Supermonos and some other EPs
Edited by Stephen65 (08/26/07 03:21 AM)
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Carol L
Reged: 07/05/04
Posts: 6968
Loc: Tomahawk, WI 45N//89W
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Hi Larry, here's what I was referring to.. see the 'X'? (Sorry about the graffiti.  )
The yellow rilles are Rimae Agatharchides, and the white rille is the one I can't locate in my resources. The white dots look like they might be a continuation.
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Carol Lakomiak, Tomahawk WI
Writing Sky at Night magazine's astrosketch page since June 2009
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larrytOMC200
sage
Reged: 07/05/07
Posts: 312
Loc: New Zealand
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Hi Carol,
Many thanks for the post showing the area you are discussing. I see it now. Well spotted by you though! It looks like you may be right, perhaps some of the 'big guns' out there might have a shot of the area and could shed some light on what it is that has been picked up?
Anyway, thanks for pointing such things out to me, it really makes me enjoy my hobby more when little details such as this seem to bring an image to life, as it were.
Keep well. Larry
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Stephen65
scholastic sledgehammer
Reged: 04/14/07
Posts: 941
Loc: Melbourne, Australia
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I had another look at this area this lunation (at about 10.00UT, 22 September), with the sunlight being at a slightly lower angle - two shots, each with FLT132 and DMK21A, first with 2x barlow, second with 5x. I can't see any evidence of a rille there, either the sun angle is wrong or its a processing artifact in Larry's original pic:
Edited by Stephen65 (09/23/07 12:20 AM)
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Stephen65
scholastic sledgehammer
Reged: 04/14/07
Posts: 941
Loc: Melbourne, Australia
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Here's the second image, taken with higher magnification:
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Megrez 90
FLT 132
Mewlon 250
Lots of XWs, an Ethos, Supermonos and some other EPs
Edited by Stephen65 (09/23/07 12:19 AM)
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Stephen65
scholastic sledgehammer
Reged: 04/14/07
Posts: 941
Loc: Melbourne, Australia
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Comparison with the images orientated the same way as Carol's illustration:
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Megrez 90
FLT 132
Mewlon 250
Lots of XWs, an Ethos, Supermonos and some other EPs
Edited by Stephen65 (09/23/07 12:39 AM)
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larrytOMC200
sage
Reged: 07/05/07
Posts: 312
Loc: New Zealand
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Stephen,
Thank you for taking the time to try and clarify the points Carol brought up.The images you posted are very good. Nice tone and contrest there!! It may well be an imaging artifact that was present in my image. If so, it is good to have the issue clered up. Thanks again, and keep well. Larry
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Jim Mosher
sage
Reged: 05/22/06
Posts: 493
Loc: Newport Beach, CA
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Carol,
I would have to agree with Larry's interpretation of the X pattern in Agatharchides P as being most likely an artifact of some sort -- possibly exaggerated by the unavoidable "connect-the-dots" tendency of the human eye.
If I am interpreting Larry's filename correctly, his image was taken at around 9:30 UT on August 24, 2007. The Sun would have been rising over the center of Agatharchides P at an angle of about 14.9 degrees. This is virtually identical to Plate F18 in the Consolidated Lunar Atlas, which also shows (with some imagination) a faint hint of an X pattern, enhanced, I think, by the strong linear shadow pattern at the tip of the SE rim, and some hint of a comparably-placed thin line of shadow in the NW rim. However, as in Stephen's example (sun angle 9.8 degrees), the sharper CLA images of Plates F16 (sun angle 10.9 degrees) and E17 (sun angle 3.1 degrees) fail to confirm the existence of any rille across the floor at this position; nor can one be seen in the several CLA images taken with the Sun from the other direction.
More importantly, as you point out, Lunar Orbiter IV Image 132H, taken with the Sun just 4 degrees higher than in Larry's view, but with far higher resolution, completely fails to confirm a rille at the position of the white line; even though it shows rilles in a roughly parallel direction on the SW floor of Agatharchides P, across Agatharchides N, and on the western floor of Agatharchides itself. These rilles/scarps are unresolved Larry's photo and in the CLA plates, but marginally detectable in Stephen's photo.
The Moon can do strange things, so one can never completely rule out the possibility of a line visible only at some exact sun and viewing angle. But it seems unlikely in this case. Both LO-IV-132H (slightly higher sun) and Stephen's photo (slightly lower sun) give a reasonably consistent picture of the existence of other lines in the same direction -- yet show no evidence of this one.
As to the "white dots" extension, as you may have already noticed, the Lunar Orbiter image suggests this is produced by a chain of small craters, rather than a rille.
-- Jim
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Jim Mosher
sage
Reged: 05/22/06
Posts: 493
Loc: Newport Beach, CA
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P.S.: I have added a slightly reduced resolution version of the Lunar Orbiter view to the-Moon Wiki page for Rima Agatharchides.
-- Jim
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frank5817
Postmaster
Reged: 06/13/06
Posts: 7212
Loc: Illinois
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Larry,
Nice images.
Frank
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My Gallery
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redsun
member
Reged: 05/28/07
Posts: 91
Loc: Missouri
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very nice shots .
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Stephen65
scholastic sledgehammer
Reged: 04/14/07
Posts: 941
Loc: Melbourne, Australia
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Ever since this discussion I have had Agatharchides P down on my list of targets to be imaged with higher resolution and different sun angles.
This image was taken at UT 20.03 on 1 March and as with others in the series it is M250+DMK21+TMB1.8x barlow+Astronomik G filter.
It does show considerably more detail than my best effort with a 5" telescope and from an opposing sun angle - the rilles on P that are hinted at in my earlier image are clearly seen, along with rilles on the floor of N and the SE-NW rille on the western floor Agatharchides itself that can be seen in the LO image Carole posted.
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Megrez 90
FLT 132
Mewlon 250
Lots of XWs, an Ethos, Supermonos and some other EPs
Edited by Stephen65 (03/16/08 12:20 AM)
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Mare Nectaris
Carpal Tunnel
Reged: 03/09/08
Posts: 1581
Loc: Toijala, Finland
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Hi Stephen!
Really an impressive shot you got there 
Very nice detail, nice smoothness. I like the atmosphere yet your picture is detailed and presents fine texture.
Thanks 
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Share - and you shall have it all
Timo Keski-Petäjä
CtheMoon
Observation shelter KuuMaja (MoonHut)
SW Evostar 120 ED APO*TAL 250K*EQ6 Pro SynScan*TeleVue Nagler Type 4 17 mm*TeleVue Panoptic 24 mm*TeleVue BIG 2x Barlow*Celestron 2x Barlow Ultima SV Series
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larrytOMC200
sage
Reged: 07/05/07
Posts: 312
Loc: New Zealand
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Stephen,
That is a superb shot of this interesting region. Thank you so much for posting it. Keep well. Larry
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Mare Nectaris
Carpal Tunnel
Reged: 03/09/08
Posts: 1581
Loc: Toijala, Finland
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... and here's LAC94 to give even better scope on the quality of Stephens shot ...
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Share - and you shall have it all
Timo Keski-Petäjä
CtheMoon
Observation shelter KuuMaja (MoonHut)
SW Evostar 120 ED APO*TAL 250K*EQ6 Pro SynScan*TeleVue Nagler Type 4 17 mm*TeleVue Panoptic 24 mm*TeleVue BIG 2x Barlow*Celestron 2x Barlow Ultima SV Series
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