New image uploaded to the files section

[Arnold Ashcraft]

A new file was uploaded to the group files section:

File Name CAshcraft_20090202_2318UT
Name of observer: Clif Ashcraft
Email address of observer: wa2...@optonline.net
Aperture of telescope: 184 mm
Focal length of telescope: 2578 mm
Type of camera used: The Imaging Source DMK31
Camera detector dimensions: 1024x768 pixels (uncropped)
Exposure information: 0.01 seconds
Time and date of exposure: 2009-02-02 UT 2318
Location from which exposure was taken: Perrineville, NJ

The observations were made under average seeing conditions,
but through a thin overcast just before a solid cloud cover swept in.
I used the DMK31 camera at the f/14 focus of my 7.25" Schupmann medial.
The resulting 30 sec long, 900 frame .avi files were processed using
Registax4 and then rotated and cropped in PhotoShop.

I note an illuminated region above and behind Faustini I have not seen
before.

Clif Ashcraft

[cano...@yahoo.com]

Clif wrote regarding his Feb. 2, 2009 image:
> I note an illuminated region above and behind Faustini I have not seen before.

Clif,

The feature behind and above Faustini is shown better on your Feb. 4
image:

http://lcross_observation.googlegroups.com/web/CAshcraft_20090204_222242UT.jpg

Looking at the "Atlas" grid, your Feb. 4 image was taken at a
libration and illuminatoin that was similar to your Dec. 8, 2008
image:

http://lcross_observation.googlegroups.com/web/CASHCRAFT_200812080127etseq2.jpg

If I am interpreting your meaning, the rising feature that you mention
is behind Amundsen, not Faustini.

Goldstone Topomap
http://lpod.wikispaces.com/February+28%2C+2008

Whitaker's 1954 map shows a crater back there behind Amundsen,
unlabeled -

http://www.lpod.org/?m=20070512

That crater is labeled Idel'son L on the USGS Digital Atlas of the
Moon Map LAC144.

http://planetarynames.wr.usgs.gov/images/Lunar/lac_144.pdf

The Gazetter of Planetary Nomenclature gives the coordindates as -84.2
_115.8_, dia. 28km - in otherwords - way the heck over the mean limb
on the farside.

If I have misinterpreted your description, please send me a marked up
photo offline or give me a "clockface" angle from the center of
Faustini or Malapert E and I'll try to track it down.

Clear Skies - Kurt

[Arnold Ashcraft]

Kurt:
See attached clipping. Here Amundsen and Faustini are overlaid with
yellow ellipses. The area I was referring to was the blue tinted
triangular patch which is actually behind both craters. It is shown
in green in the USGS Digital map. I assumed it was the region called
by you in an earlier email as the Atkin highland. Idel'son L is the
white rim to the left of the blue tinted area in the clip below (I
believe).
Clif

[cano...@yahoo.com]

That sounds right to me. - Kurt

[Jim Mosher]

Clif,

Lest there be any confusion, I believe the feature Kurt was referring
to is the one informally known as the "South Pole - Aitken Basin"
(often abbreviated SPA):

http://the-moon.wikispaces.com/South+Pole+-+Aitken+Basin

Aitken itself is actually a farside crater far removed from the south
pole. The SPA depression is evident in all altitude maps (meaning that
it is indeed surrounded by "highlands"), but trying to identify any
specific feature as being a part of its rim is frustrating at best.
The various peaks informally known as the Leibnitz Mountains
(Whitaker's designations of specific peaks may or may not agree with
those of earlier selenographers) are sometimes cited as possible
examples. Most of the Leibnitz peaks would (I believe) be in the
foreground in your strongly librated image.

Independent of nomenclature, these two attachments may help to clarify
what you were seeing.

In the first I have compared your Feb 2 image to the Clementine
basemap and to a piece of a photo taken a year earlier by Belgian
amateur Bart Declercq:

http://bartcentral.dommel.be/Astronomy/Moon/2008-01-16/slides/Lunar_Southpole_20080116_19h10UT.html

Bart's image has been remapped to the same geometry as yours, but to
make the limb features a bit clearer in the Clementine image I have
artificially tipped all three a bit by by increasing the libration in
latitude to -10 deg from its correct value of -6.5 deg. I believe the
area you are asking about is the diamond-shaped patch pointed to by
the yellow arrow? It appears to lie roughly along, but limbward from,
a line through Shoemaker, Faustini and Idel'son L, which you correctly
pointed out (I think) as the crater on the far rim of Amundsen.

The second attachment shows an aerial view of the Clementine basemap
with the theoretical limit of visibility for a smooth Moon at the time
of your Feb 2 photo indicated by a pale blue line. The darker
vertical red and blue lines are the start and end of the theoretical
terminator. They are straight and vertical because by chance your
photo was taken at a moment of almost perfect 50% illumination from
your site. In the second attachment, I have shaded in blue something
that looks rather like an ancient crater beyond Amundsen and Faustini.
The diamond shape pointed to in the first Clementine simulation is
produced by the left part of this shaded area, bordered by the
shadowed ridge connected to Idel'son L. Based on the similarity in
shapes, I would tend to think that the same physical area accounts for
the diamond-shape in your photo; but appearances can be deceiving
because the Clementine simulation does not take into account the ups
and downs of the topography (causing some features to be blocked from
view by others), nor is the Clementine lighting likely to be an exact
match for that at the time of your photo.

Bart's somewhat clearer Earth-based photo, and others like it, make
this area beyond Amundsen and Faustini appear to be a relatively
smooth plain bordered by more distant hills. Much of the blue shaded
area in the Clementine basemap is probably hidden by the elevated area
along the right rim of Amundsen. The string of bright dots seen along
the extreme limb in the Earth-based photos is most likely a
combination of the ridge connected to Idel'son L and the peaks under
what is marked as "Clif's limb" in the second Clementine attachment.
It doesn't appear that anything beyond that point is visible, probably
because the terrain is generally sloping down. It will be interesting
to see what simulations made from digital elevation maps show: if they
are accurate they should resolve exactly what should be seen at each
position (as perhaps do the IOTA limb maps?).

In your Feb. 4 photo I think the diamond-shaped area was less visible
both because it had moved closer to the limb and because the
terminator had swung around counterclockwise, giving a lower sun
angle, and more shadowing from Amundsen and surroundings. It was more
visible in Bart's image both because the terminator had swung around
less and because the Sun's latitude in January 2008 was 0.9 S compared
to 0.1 N on Feb 2 this year, putting more light into the extreme south
polar area at each angle of azimuth.

Incidentally, as Kurt points out, Idel'son L is at 115.8 east
longitude, which in some sense makes it 25.8 degrees beyond the limb
at 90 deg E/W; but as polar explorers know, at high latitudes large
differences in longitude can occur over short distances. Even at zero
libration, Idel'son L is only about 2.8 deg (~85 km) beyond the limb
as measured from the Moon's center, and at the time of your photo it
was well onto the disk (86.6 degrees from the center). Although it is
possible to see the tops of peaks beyond the theoretical limb, the
ones seen in these photos are probably at the limb or on its Earthward
side.

-- Jim

P.S.: it looks from Bart's photo like the very bright patch seen just
to the left of the tip of the yellow arrow in your photo (in the first
attachment) is a relatively sheer slump-face in the inner wall of
Amundsen, favorably disposed for reflecting light towards Earth.
Faustini seems to catch the light in a similar way at its right-hand
end. Just in front of the sheer wall in Amundsen, Bart's image
provides a nice view of Nobile and the unnamed crater straddling its
right hand rim (see labels in second attachment). The similar-sized
crater touching Faustini's limbward rim is much harder to see.

[Arnold Ashcraft]

Jim:
Thanks for the clarifications. I am beginning to get a pretty good
idea of the south polar geography now. Of course, NASA is now
talking about a North polar target. I am looking forward to the
positive libration nod coming up. Don't tell Murphy.
The image taken by Bart Declercq is certainly a nice one. Very
similar in all respects to my picture, except a whole lot better
resolution.
Clif

> <Clif_Bart_Clementine_comparison.JPG><ClifAshcraft_area_Clementine.JPG
> >

[cano...@yahoo.com]

Clif, if you can get ahold of it, you may find this recent article by
Spudis discussing the geologic setting of the South pole with respect
to the SPA basin interesting reading.

Spudis, P.D., Bussey, B., and Plescia, J. et al. July 2008. Geology
of Shackleton Crater and the south pole of the Moon. Geo. Res. Ltrs.
35:L14201. url: http://adsabs.harvard.edu/abs/2008GeoRL..3514201S

Many of the massifs in the area - including our favorite landmark
Leibntiz Beta - are part of an outside rim edge of the massive 2600km
diameter SPA basin.

- Kurt

[Arnold Ashcraft]

Kurt:
That reference is off limits for me. When I tried to download it, I
was asked for a user ID and password.
Clif

[cano...@yahoo.com]

Next time you are around a university library, try a terminal there. -
Kurt

On Feb 7, 6:03 pm, Arnold Ashcraft <wa2...@optonline.net> wrote:
> Kurt:
>         That reference is off limits for me.  When I tried to download it, I  
> was asked for a user ID and password.
>                 Clif