South Pole LCROSS target zone imaging 2009-08-09 11_23UT (corrected)

[cano...@yahoo.com]

South Pole LCROSS target zone imaging 2009-08-09 11_23UT

A unseasonably cold night dropped nighttime-low temperatures from
26deg C to 15C and stabilized the air. The following two images are
of the south pole region encompassing the current 7-2009 LCROSS
potential target list. This is intended to be the first in a planned
series (weather permitting) through August 11 (73.8% illuminated
fraction) and August 12 (64.2% illuminated fraction). The intent of
this series is to gather images of analogous lighting and libration to
that that will be seen on the Oct. 9 11:30UT LCROSS impact as a
finding aid to general public and amateur viewers.

Image info:
Date-UTime, OP and target are encoded in the file names.
Local circumstances:
Lunar Age: 18.4 days
Illuminated fraction: 89.2%
Altitude +45.25d
Meade DSIProI
Meade ETX125 2x barlow extender estimated at approx. f/30, unguided
Seeing: Poor. 2-3 out of 5 secs stable

Images can be found in directory:

http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090809_1123UT/

Direct urls are:

A. - South Pole Region - Unlabeled - emphasizing "Malapert shadow
hole"
http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090809_1123UT/20080809_1123UT_OPW111d52mN40d46mKAF0_SP.jpg

http://tinyurl.com/mart6v

B. - Same as A - LTVT aligned
http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090809_1123UT/20080809_1123UT_OPW111d52mN40d46mKAF1_SP_LTVTUnlabel.jpg

http://tinyurl.com/lwf74e

C. - Same as A - LTVT aligned with LCROSS target craters labeled
http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090809_1123UT/20080809_1123UT_OPW111d52mN40d46mKAF3_SP_LTVTLabel.jpg

http://tinyurl.com/lbv6ae

D. - Same as A - Fits version
http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090809_1123UT/20080809_1123UT_OPW1

11d52mN40d46mKAF0_SP.fit

E. - Experimental utlra-overexposure - brings out hidden Shoemaker in
"Malapert shadow hole"
http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090809_1123UT/20080809_1123UT_OPW111d52mN40d46mKAF5_Shoemaker_InShadow.jpg

http://tinyurl.com/ncjgcb

F. - Same as E - LTVT aligned
http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090809_1123UT/20080809_1123UT_OPW111d52mN40d46mKAF6_Shoemaker_InShadowLTVT.jpg

http://tinyurl.com/lrhf2b

G. - Same as E - LTVT aligned with LCROSS target craters labeled
http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090809_1123UT/20080809_1123UT_OPW111d52mN40d46mKAF7_Shoemaker_InShadowLTVT_Label.jpg

http://tinyurl.com/lc7a74

H. - Same as E - Fits version
http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090809_1123UT/20080809_1123UT_OPW111d52mN40d46mKAF5_Shoemaker_InShadow.fits

Items E through H are experimental ultra-overexposure designed to see
how faint my camera setup can penetrate into the "Malapert shadow
hole." The ultra-overexposure brings out Shoemaker hidden in the
Malapert shadow.

I do not own Photoshop. It would appreciated if someone would
experiment with the images in Photoshop to cut, paste and blend the
ultra-contast view of Shoemaker in the interior of the "Malapert
shadow hole" into the normal contrast image, item "A" above.

I plan to try this again, but using two parallel aligned polarizes to
reduce glare from the Moon's surface reflection.

Another possible processing option might be to apply the Photomatix
High Dynamic Range software featured in the June issue of Sky &
Telescope inorder to generate an image that combines a normally
exposed bright surface with an over-exposed image of shadowed areas.

In this lunar age 18.4 day image, the usual finder crater suspects are
visible: Moretus, Simpelius crater asterism (which looks like a
snowangle that you made as a child), Malapert E on Leibnitz Beta,
Schomberger C and Malapert K. Faustini is slightly over Leibnitz
Beta.

Although I have not attempted autoguiding, potential lunar bright
spots that hold during bad seeing moments include Casatus C (left-side
middle of Item A), and further away - Rutherfurd in Calvius. At
first, Simpelius J and the central peak of Moretus appeared like good
guide target candidates, but in poor seeing they smeared and became
invisible.

On the morning of 20090807, I also looked at the near full Moon in
order to consider how to direct general public inquiries to find the
lunar south pole. At times, the parallactic angle of the Moon can fool
beginners (and intermediates) as to the location of the south pole. I
found the following low-power rules of thumb useful:

1) (For beginners), on the Moon the east west directions are
reversed. The eastern Moon corresponds to your geographic western
horizon. The western Moon corresponds to your eastern geographic
horizon.

2) Mentally draw a line between Tycho through Rutherfurd. (Rutherfurd
is young bright ray crater in the southeast corner of Clavius.) At the
southern limb, the line intersects with Cabeus.
See diagram:
http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090809_1123UT/20090807SouthPole%20SiteLines.jpg

http://tinyurl.com/ldrj49

Mentally drawing a line between the central peaks of Tycho, along the
eastern edge of Clavius and the central peak of Moretus, extends to
Malapert and the south pole on the southern limb.

3) Mentally draw a line between bright crater Kundt, through the
central peak of Tycho. It intersects the southern limb at Cabeus.
Malapert is one or two Tycho crater diameters to the lunar east along
the southern limb.
http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090809_1123UT/20090807SouthPoleSiteLines.jpg

http://tinyurl.com/krz4ae

Clear Skies - Kurt

References:

NASA LCROSS Team, 7-14-2009, Short List of LCROSS Candidate Impact
Craters
http://www.nasa.gov/mission_pages/LCROSS/main/candidate_craters_story.html

Rick Baldridge, LCROSS Google Groups Moderator, Call for images,
7-12-2009
"I urge everyone with high-resolution planetary imaging capability to
attempt a detailed image that can be posted on the NASA website to
guide would-be imagers/videographers to the impact location."
http://groups.google.com/group/lcross_observation/msg/30a27eb02b531a48

[cano...@yahoo.com]

On Aug 9, 6:32 pm, "canopu...@yahoo.com" <canopu...@yahoo.com> wrote:
> South Pole LCROSS target zone imaging 2009-08-09 11_23UT

<snip all>

Stefan Lammel graciously provided a rough Photoshop merge of my two
south pole images using Photoshop.

http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090809_1123UT/20080809_1123UT_OPW111d52mN40d46mKAF8A_ShadowMerge.jpg
http://tinyurl.com/m8cehk

This is a proof-of-concept demonstration of one possible technique for
capturing the faint LCROSS impact ejecta curtain as it rises from a
crater in shadow and then producing an asethetic image. In the merged
imaged, one can make out a small part of Shoemaker's rim and clearly
see what I believe is Shackleton in the background of the shadow
area.

Clear skies, Kurt

[cano...@yahoo.com]

On Aug 10, 4:54 pm, "canopu...@yahoo.com" <canopu...@yahoo.com> wrote:
> On Aug 9, 6:32 pm, "canopu...@yahoo.com" <canopu...@yahoo.com> wrote:> South Pole LCROSS target zone imaging 2009-08-09 11_23UT
<snip all>

Visually observed the south pole on 200-08-10 08:23UT with the Meade
125 ETX. A 2"-4" small bright line could be seen in darkness behind
and slightly above Leibnitz Beta and a few arcsecs to the lunar east
of the Malapert E crater centerline. I took this to be part of the
Faustini rim seen on the group's March images here. No images made do
to work-day time restrictions. - Clear Skies, Kurt

[cano...@yahoo.com]

On Aug 10, 6:04 pm, "canopu...@yahoo.com" <canopu...@yahoo.com> wrote:
> On Aug 10, 4:54 pm, "canopu...@yahoo.com" <canopu...@yahoo.com> wrote:> On Aug 9, 6:32 pm, "canopu...@yahoo.com" <canopu...@yahoo.com> wrote:> South Pole LCROSS target zone imaging 2009-08-09 11_23UT
<snip all>

I had a few moments to image last night and made a technically poor
image (20090811 at 0937UT) using a Meade ETX 125 at about f/30 and an
older DSI-ProI. The image captures lunar south pole shadowing
analogous to what will appear on the morning of the LCROSS impact. For
illumination and sun-angle comparision, I also took a prior image on
August 9 at 11:37UT:

Lunar libration data for images and impact
Source: LTVT ephemeris data, topocentric W111.8 N41.8
Date-TimeUT libr_lat lib_long colong illumfrac sunalt_MalpertE
20090811 0937 -6.1 -6.5 157.1 74.4 -0.5
20091009 1130 -3.5 2.8 158.2 70.9 1.6
20090809 1123 -5.2 -6.0 133.7 89.4 2.9

Date-TimeUT Lunar age (days)
20090811 0937 20.3
20091009 1130 20.6
20090809 1123 18.4

Item I. - South pole image 20090811 at 9:37UT
http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090811_0937UT/20090811_0937UT_OPW111d52mN40d46mKAF0_SP.jpg
http://tinyurl.com/p3bdlk

This image is a single frame - no stacking or deconvolution - and has
been unsharp masked and gamma processed. While technically below the
prevailing acceptable quality for amateur lunar imaging standards, it
does record illumination and shadow conditions analogous to the LCROSS
impact set for Oct. 9, 2009.

Item J. - Same as item I but LTVT labeled with craters
http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090811_0937UT/20090811_0937UT_OPW111d52mN40d46mKAF2_SP_Label.jpg
http://tinyurl.com/pnmgta

Item K. - Same as item I but hyperexposed to see if more detail could
be extracted from the "Malapert dark hole".
http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090811_0937UT/20090811_0937UT_OPW111d52mN40d46mKAF1_SP_HyperExpos.jpg
http://tinyurl.com/qty3q8

(The Item K image is a single frame - no stacking or deconvolution. A
stacked set of images also failed to bring out any more detail than
that seen in the single frame image.)

In the hyperexposed version, a snipet of the Faustini crater rim can
be seen to the right of and below Malapert E. (Compare Item K to the
best of the March 2009 south pole images.) Visually, this Faustini
crater rim snipet was quite easily seen with 125mm of aperture.

All images are in directory
http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090811_0937UT/

Unlike my August 9 image, hyperexposing the Malapert "dark hole" did
not bring out any additional detail. Compare Item K above with my Aug.
9 hyperexposed image:

E. - Aug. 9 experimental hyperexposure - brings out hidden detail in
the "Malapert dark hole".
http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090809_1123UT/20080809_1123UT_OPW111d52mN40d46mKAF5_Shoemaker_InShadow.jpg
http://tinyurl.com/ncjgcb

I attributed the difference in the effectiveness of pulling detail out
of a shadowed region to sun angle. On Aug. 9 the Sun angle at
Malapert E was 2.9 degs. I believe at this angle, the Sun was also
hitting the hidden backside of Leibnitz B and created a backscatter of
light that faintly illuminated the interior of the Malapert "dark
hole". On Aug. 11, the sun angle at Malapert E was -0.5 degrees, and
there is no backscatter off the backside of Leibnitz Beta into the
Malapert "dark hole".

I was unable to image on the morning of the 12th, but observed
visually at 2009-08-12 14:00UT during daylight. By then, a
characteristic "dark canyon" for this colongitude (172 degs) leading
from Moretus to Malapert had formed. The "hole" consists of Short and
series of depressions lunar east of Newton B, M, G, A and ending with
Newton B. This extended dark canyon trails lunar south down to the
Malapert dark hole. It can be seen in Westfall's Atlas in plates 174-
S and 179-S.

The imaging lesson learned comparing the Aug. 9 and 12 images are that
faint features can be extracted by hyperexposure notwithstanding lunar
glare emitted from features on the bright side of the terminator.

This result relates to two hypothesized impact ejecta curtain
scenarios for the October 9 LCROSS impact.

The first ejecta cloud scenario is the conservative LCROSS team
planning assumption - a 10km wide by 5km high lampshade figure with a
2.5 km line rising above the rim of a permanently shadowed crater rim
and being visible from Earth.
The second ejecta cloud scenario is a more liberal hypothetical
assumption of a 20km by 20km curtain capable of reflecting light that
can be seen by a 254mm (10 inch) aperture amateur class telescope from
Earth.

For scale, the diameter of Malapert E is 17km.

Using my Aug. 11 image, I added scaled ejecta cloud curtains for these
two hypotheticals. Using 17km diameter Malapert E as the image
scalar, the Aug. 11 image works out to an image scale of about 600
meters per pixel. Here's the Aug. 11 image with scaled figures for
the two ejecta cloud hypotheticals:

Item L. - Sames as Item I with scaled ejecta cloud hypotheticals -
brightness of the cloud is abitrary
http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090811_0937UT/20090811_0937UT_OPW111d52mN40d46mKAF0_SP_Illustrated.jpg
http://tinyurl.com/prdaku

The luminance of the two scaled ejecta curtains is arbitary and is not
intended to represent the actual, but presently unknown, brightness of
the LCROSS impact ejecta curtain.

The implication of these hypothetical cloud scales for the hyper-
exposure imaging method is that the bright-border effect seen in the
Aug. 9 image indicates that a 10km by 2.5km high ejecta curtain would
be overwhelmed by the hyper-exposure border glare. See the following
images showing the hyperexposure border glare where the southern lunar
limb outline meets the dark sky -

E. - Aug. 9 Experimental hyperexposure - brings out hidden Shoemaker

in "Malapert shadow hole"
http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090809_1123UT/20080809_1123UT_OPW111d52mN40d46mKAF5_Shoemaker_InShadow.jpg
http://tinyurl.com/ncjgcb

Item K. - Aug. 11 Experimental hyperexposure. Same as item I but
hyperexposed to see if more detail could be extracted
http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090811_0937UT/20090811_0937UT_OPW111d52mN40d46mKAF1_SP_HyperExpos.jpg
http://tinyurl.com/qty3q8

Conversely, a 20x high ejecta curtain would rise high enough above the
hyperexposure border glare to be captured by imaging - assuming the
ejecta curtain reflects enough sunlight to be detected from Earth.

The above discussion is not intended to say anything about the
likelihood of visually observing the ejecta curtain. As noted above
with respect to the August 11 image, the Faustini crater rim snipet
was quite easily seen visually with 125mm of aperture. In the
hyperexposure Aug. 11 image, the Faustini rim snipet is barely
visible.

Clear Skies - Kurt

References:

Malapert E diameter
http://planetarynames.wr.usgs.gov/jsp/FeatureNameDetail.jsp?feature=71175

[cano...@yahoo.com]

On Aug 12, 10:22 pm, "canopu...@yahoo.com" <canopu...@yahoo.com>

wrote:
> On Aug 10, 6:04 pm, "canopu...@yahoo.com" <canopu...@yahoo.com> wrote:> On Aug 10, 4:54 pm, "canopu...@yahoo.com" <canopu...@yahoo.com> wrote:> On Aug 9, 6:32 pm, "canopu...@yahoo.com" <canopu...@yahoo.com> wrote:> South Pole LCROSS target zone imaging 2009-08-09 11_23UT
> <snip all>

To wrap this up, here's a couple of aerial views above the south pole
on 8-9 and 8-11 generated using the LTVT luna-tarium engine. Although
technique not up to standard and the second image is not well
registered, one can still get a sense of the evolving shadow across
two todays. Last night I got clouded out and could not capture a
three night in the intended series.

The next analogous LCROSS impact shadow and libration date is Sept
10. Hopefully someone else can capture better images than I did
during this August libration window to aid the general public during
the Oct. 9 impact.

Aerial View - LTVT - of August 9 11:23UT image
http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090809_1123UT/20080809_1123UT_OPW111d52mN40d46mKAF9_SP_LTVTAerial.jpg
http://tinyurl.com/mlrh33

Aerial View - LTVT of August 11 9:37UT
http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090811_0937UT/20090811_0937UT_OPW111d52mN40d46mKAF4_SPAerial.jpg
http://tinyurl.com/kqg4wr

Clear Skies - Kurt

[Jim Mosher]

Kurt,

Thanks for the interesting contribution. Not being an experienced
imager, some of the items in the initial post were a bit confusing to
me. I'm not sure, for example, why the main disk of the Moon turns
black when you increase the exposure, giving a "solarized"
appearance. Is some kind of digital counter overflowing? If so, why
is it stuck on black and not showing another cycle of gray levels?

Also, your raw image "20080809_1123UT_OPW111d52mN40d46mKAF0_SP.jpg"
(shouldn't it say 20090809 ?) appears to be compressed vertically
compared to the geometry one might have expected on 9 Aug 2009. Is it
using non-square pixels? I am guessing it might be in a video format
that requires 4/3 X vertical expansion to display correctly on the
typical square-pixel computer monitor? Or is some other ratio
required?

--

As previously mentioned, lighting at the Moon's poles is essentially
determined by the Sun's longitude (or colongitude, if you prefer) and
latitude. The first determines the direction (azimuth) from which the
Sun's rays come, the other how high or low above the horizon it will
be (sun angle). "Age" and "percent illumination" (of the Moon as a
whole) may be helpful for orientation, but to the extent they dictate
looking at some other date they are irrelevant.

The attachment may be helpful for correctly identifying the features
you see in what you call the "Malapert shadow hole" and for
understanding why they were hard to see. It shows views of the south
pole posted on the internet with the sun at a similar longitude, but
with slightly higher and lower latitudes than you experienced on 2009
Aug 09 at 11:23 UT (the Sun's longitude and latitude on the Moon are
listed on the credit line above each frame).

The top image, posted by Helmut Groell, was obtained on 2008 Oct 18 at
01:02 UT :

http://lpod.org/coppermine/displayimage.php?pos=-3679

Note that the sun angle at the Moon's south pole becomes more positive
(i.e., the lighting becomes stronger) as the Sun's latitude (something
that varies in an approximately annual cycle) becomes more negative,
and that the -1.4° solar latitude in Helmut's image is very close to
the -1.5° solar latitude that will be experienced in early October
(although, like your 9 Aug observation, his solar longitude
corresponds to the azimuth that will be seen about two days before the
impact).

In Helmut's image, Shackleton is visible directly under the "lon"
label. The bright streak under and slightly to the left of the "SS"
label is an unnamed elevation. Shoemaker is the much larger crater
ellipse to the lower left of Shackleton; while Faustini's ellipse is
to Shoemaker's upper left.

The bottom image is cropped from a full disk mosaic with 22 parts
taken by the AstronoMinsk imagers on 2008 Aug 19 at "22:52 UT":

http://objectstyle.org/astronominsk/Moon/Moon2008/Moon_20080819_en.htm

Since the Sun is lower, only the near rim of Shackleton can be seen,
the outline of Shoemaker is much harder to detect, and Faustini has
essentially disappeared, leaving only a tiny fragment of sunlit rim on
the right.

In the center panel I have slightly increased the "gamma" of your
image to bring out the features in the "hole" (which, as you
demonstrate, are brought out even more by increased exposure). All of
these seem to be pretty much what one would expect from the pattern of
sunlit ridges seen in the upper and lower panels. The reason your
camera could detect them only with increased exposure would seem to me
to be a matter of lower resolution (smearing them out into darkness)
coupled with some difference in the linearity settings/processing
controlling how low light levels are displayed. It seems unlikely to
me that the success of prolonged exposures in bringing out additional
features demonstrates indirect illumination of those features by
sunlight scattered from nearby peaks and ridges: all the features
brought out by the deeper exposure would have already been present at
the lower sun angle photographed by the AstronoMinsk images. And
there is no reason to think the AstronoMinsk image is showing anything
other than direct lighting. The patterns it shows are logical
extensions of those seen by Helmut with a higher Sun; and since the
scattered light would be expected to come from different direction(s)
than the direct sunlight, it seems difficult to explain why the
pattern produced by it would blend so neatly into that produced by
direct light.

--

Your instructions regarding Kundt and Tycho seem helpful for locating
the south pole at Full Moon.

For locating the impact site on October 9, 2009, the Mario Weigand
full disk mosaic from October 20, 2009:

http://www.skytrip.de/monvid241c.htm

continues to be a good match for both the Sun's longitude and
latitude, as well as for the libration in latitude. If corrected for
the difference of libration in longitude, it should make a pretty good
finder chart, once the target has been announced. The general public
should have little trouble finding the south pole simply by telling
them to look for where terminator crosses the "battered" end. Once,
there, Moretus will be an unmistakable landmark, and from there, they
can crater-hop to the target point using something like Mario's image
(with the impact location marked on it) as their map. This certainly
worked for the Kaguya impact -- where the Moon's appearance and the
location of the impact flash in relation to it were essentially
exactly as predicted prior to the event on the basis of archival
photos :

http://ltvt.wikispaces.com/Kaguya+Impact

and there is no reason to think it won't work for LCROSS:

http://ltvt.wikispaces.com/LCROSS+Impact

Helmut's image would make an excellent finder chart if the impact was
scheduled for October 7th (something that is not expected to happen).

-- Jim

[cano...@yahoo.com]

On Aug 14, 5:41 pm, Jim Mosher <jimmos...@gmail.com> wrote:
<snip all>

Jim,

The main take away point is that hyper-exposure to bring out faint
otherwise _visually_ invisible detail provides an alternative means by
which impact imagers may practice before the actual October impact.
It presents an alternative means to the previous consenus practice
method of finding the faintest star that can be imaged as it is
eclipsed by the bright limb or near the poles.

In this regard and with respect to the acknowledgements stated below,
the central warrant of the prior post holds. Imaging of faint limb
objects not otherwise visible with the naked eye illustrates that CCDs
provide an additional photographic magnitude reach beyond the visual
that is not completely overwhelmed by the glare from the bright limb.
That is an unremarkable and expected qualitative note on lunar
imaging.

To complete analysis of this main point, the next question is
quantitative - how faint are faint features recovered through
imaging. The rough preliminary answer is an additional 1.5 mags from
the mid-tones of a lunar image. However, to complete an analysis, a
nearby open cluster would have to imaged at the same setting and the
same approximate altitude as the Moon is imaged. During the Sept.
9-11 lunation and imaging opportunity, M45 and the Moon will be
favorably positioned to gather CCD photometry data to answer such a
question.

> The attachment may be helpful for correctly identifying the
> features you see in what you call the "Malapert shadow hole"

Your criticism that I have improperly identified the faint background
features is a correct and is acknowledged. I suspect the faint
features in the background of the Malapert dark hole are part of
either a rim of Shoemaker or the highlands between Shoemaker and
Shackleton. See site line markups on supplmental panel image:

http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090809_1123UT/20080809_1123UT_OPW111d52mN40d46mKAF9B_DiscussionPanel.jpg

http://tinyurl.com/mlmseo

> The reason your
> camera could detect them only with increased exposure would seem to me
> to be a matter of lower resolution (smearing them out into darkness)
> coupled with some difference in the linearity settings/processing
> controlling how low light levels are displayed. It seems unlikely to
> me that the success of prolonged exposures in bringing out additional
> features demonstrates indirect illumination of those features by
> sunlight scattered from nearby peaks and ridges: all the features
> brought out by the deeper exposure would have already been present at
> the lower sun angle photographed by the AstronoMinsk images. And
> there is no reason to think the AstronoMinsk image is showing anything
> other than direct lighting.

Your criticism is correct that the faint features in the background of
the Malapert dark hole are in direct sunlight and are not illuminated
by backlighting as I originally supposed.

However, the main warrant of the exercise and purpose of the analysis
still holds. The context of this test was to find alternative to the
practice imaging of faint objects near the poles to the method of
finding the faintest star that can be imaged as it is eclipsed by the
bright limb or near the poles.

The faint features in the background (with one exception) were not
detected _visually_ at 475 power (1900 fl / 4mm ep). They were
however brought out by CCD imaging. And they were imaged even though
the area is framed by fully illuminated lunar surface on the bright
side of the terminator. Glare is not preventing the capture of the
additional detail.

In the attached discussion panel, I have included a raw jpg export on
one fits frame and labeled the frame with the raw ADUs for six
individual pixels.

The middle frame is a Goldstone radar based topographic map oriented
using your LTVT sofware to the circumstances of Aug. 11. Using, LTVT,
I also gathered sun angle ephemeris data for each of the six pixels.
That data is listed in tabular form as follows:

Pixel region - ADUs - x-y coord in raw FITS - emphermis sunangle at
pixel
Leibnitz beta bright spot - 27692 - x180y206 - SA 3.6°
Shoemaker back rim moderate spot - 7690 - x234y184 - SA 0.3°
Shoemaker back rim faintest spot - 6243 - x218y186 - SA 0.3°
Moretus central peak bright face - 31564 x266y426 - SA 15.7
Dark half of Malapert E - 13242 x156y206- SA 3.2°
Simplieus J - 32466 - x96,y260 - SA 8.9°

While this is a clear filter image without two filter transforms, raw
differential magnitudes based on the ADU counts indicates that
relative brightness (27692/6243=4.4) between the bright spot on
Leibnitz beta and the faint line in the background (at pixel x218y186)
is about 1.6 magnitudes.

Similar photometry cannot be extracted from the technically superior
Astronominsk and Groell images because those are probably post-
processing, gamma enhanced and stacked images. Similarly, we have no
information from the raw source images or whether when those images
were taken, what features where or where not _visually_ as opposed to
photographically detected.

You may be making an interpretative error by not accounting for the
difference by visual observation and photographic seeing. That faint
detail is captured on gamma enchanced images by Astronominsk and
Groell does not imply that all of the faint detail was or could have
been observed visually.

The above magnitude computation is a relative measurement. To really
be useful for ascertaining whether the LCROSS ejecta curtain can be
captured by imaging, an rough absolute magnitude of the features at
various sun angles would need to be determined. A suggested procedure
for that will be discussed in a follow-up post.

Nonetheless, the technique illustrated is both relevant and highly
valuable as a pre-event practice method for amateurs desiring to image
the LCROSS image. The faint features in the Malapert dark hole are
illuminated by extremely low elevation sunlight - 0.3 degs in my image
and 0.2 degs in the AstronoMinsk image. That they are faintly
illuminated by very low level sun angle light verses backlighting is
not fatal to the practice technique. The point is they are much
fainter than the foreground and therefore are useful for imaging
practice.

The LTVT software engine can be useful in identifying craters at
either pole on almost any night of a lunation with analogous
illumination at extremely low sun angles. Practice imaging becomes
seeing how far into or near the terminator that the faintest feature
can be recovered out of the _visual_ blackness.

This practice method is less time constrained than trying to find the
rare star of the right magnitude (between mag 7 to 0) to graze or slip
past a pole and then taking an image as it passes.

> [W]hy the main disk of the Moon turns

> black when you increase the exposure, giving a "solarized"
> appearance. Is some kind of digital counter overflowing? If so, why
> is it stuck on black and not showing another cycle of gray levels?

The effect is camera and software related and may be specific to the
Meade DSI Pro One used. The bottom frame of discussion panel includes
the final stacked image with a histogram from one frame of the stacked
sources fits images. When the Meade DSI Pro exposes past its well
capacity, it offsets the pixel value by minus 2^16 (65536) - making
the pixel value negative. Since zero is the value of a black pixel,
overexposed pixels and those stacked pixels that exceed 65536 are
rendered black by Registax. In the final image, negative pixel values
are removed by clipping.

> "Age" and "percent illumination" (of the Moon as a
> whole) may be helpful for orientation, but to the extent
> they dictate looking at some other date they are irrelevant.

Your conclusion does not follow from the observing context.

The remaining analogous date (9-10) suggested by Rick Bladridge is not
a precise replication of the conditions at the time of impact. The
libration in latitude is significantly different (-5.4 on 9-10 verses
-3.5 on 10-9) than what will occur at the time of impact. Similarly,
the libration in latitude condition on 8-11 significantly different
(-5.9 verses -3.5 on impact day).

Rough analogous dates are not irrelevant due to this lack of
precision. Imagers, particularly DSO amateurs with little high-
resolution lunar imaging, who will be successful are those that
practice imaging faint features surrounded by the much brighter
terrain on the limb. Location and tracking of the correct lunar
feature at f/30 and higher is not a trivial task. Practicing good
exposure of faint features should occur without regard to
pragmatically unattainable precision of libration in longitude and
latitude that will exactly replicate the conditions of impact. On the
date of the impact, the faintly illuminated background features will
not be visible but fortunately will be visible one last time around
Sept. 10 should imagers wish to practice their exposure technique.

Again, Jim's LTVT software engine can be useful in identifying craters
at either pole on almost any night of a lunation with analogous
illumination at extremely low sun angles.

As can be seen by comparing the top and bottom images of the
discussion panel, hyperexposure with stacking can bring out
considerable more relative faint detail and more detail than will be
seen _visually_. That the Gorell and Astronominsk images used larger
apertures and better equipment misses the central point. The
important speculative question is what relatively more faint detail
could they have brought out with their superior equipment had the
objective of their imaging sessions been to purposefully try to more
faint image detail at the south pole.

> Also, your raw image "20080809_1123UT_OPW111d52mN40d46mKAF0_SP.jpg"
> (shouldn't it say 20090809 ?) appears to be compressed vertically
> compared to the geometry one might have expected on 9 Aug 2009. Is it
> using non-square pixels?

Your criticism that the image has a processing error is correct. Meade
DSI Pro I wells have a rectangular shape. I believe the error is that
I rotated the image before I corrected for the rectangular pixels. It
should be done the other way around - correct for the pixel size first
and then rotate.

> The general public should have little trouble finding the south pole simply by telling them to look for where terminator crosses the "battered" end.

This reasoning about the abilities of the general public errs based on
experience. The most likely scenario will be that the inexperienced
general public will start observing two to four days before the impact
date to get oriented to the lunar disk and in response to pre-impact
publicity. At that time, the terminator's "battered" end does not
disappear at the south pole and illumination creates a false south
pole dark hole asterism that looks very similar to the Malapert dark
hole, but the east of the true south pole along the limb. One lunar
observer here was fooled by it and made a "south pole" image east of
Scott along the lunar limb. When I began imaging on August 7 - being
hurried after a long-day at work - I made exactly the same error and
made a wonderful image of the wrong spot on the limb - and I'm no
lunar neophyte. that was the motivation in devising the supplemental
site light technique. Closer to the full Moon, the Moretus, Simpelius
and Schomberger landmarks are almost invisible in the brighter flat
lighting.

A better star party mentoring technique would be to use site lines
that I suggest, because they can be traced to the correct spot on the
lunar limb even at high levels of illumination. The traditional route
that you suggest (as has been discussed in this newsgroup for
sometime) is appropriate for star party mentoring on the evening
before and the night of impact. But at higher levels of lunar
brightness, the Morteus siteing route does not work very well.

On August 14, the Moon traveled through the apparent center of the
Pleiades cluster. Due to a cloud-out and technical problems, I was
unsuccessful in capturing a south pole image and a magnitude
calibration image of Alcyone. Nonethless, the exercise suggests a
simpmle technique to establish rough absolute magnitudes for the
bright and faintest features recoverable at the south pole with a CCD.
I will discuss the August 14 test run in a follow-up post.

Clear Skies - Kurt

[Jim Mosher]

Kurt,

My apologies for missing your "take away point" about the low-light
sensitivity of photographic observations. In an age where amateurs can
successfully photograph faint nebulae from suburban backyards, I
certainly agree that cameras can, with long enough exposures, see
things invisible to the eye. A common lunar example would be the many
photos on the internet showing clear detail on the Earthshine lit side
of the Moon at phases and under conditions where the Earthshine cannot
be seen at all by most of us.

Part of the reason for my confusion may have been that in your earlier
postings the only comment I found comparing visual and photographic
observations was the twice-emphasized statement: "with respect to the

August 11 image, the Faustini crater rim snipet was quite easily seen
visually with 125mm of aperture. In the hyperexposure Aug. 11 image,

the Faustini rim snipet is barely visible." I had apparently
incorrectly interpreted this to mean that with your set-up "hyper"
exposure, or more, was necessary to bring out the faintest details
visible to the eye. If I understand correctly now, your difficulty in
photographing the "Faustini rim snippet" on August 11th was the
exception to the rule, and at other positions and at other times the
over-exposed images brought out features completely undetectable to
the eye?

--

Regarding my own writing, I am sorry to see that it, too, is so
subject to confusing interpretations. I never meant to say that
observations made with similar lighting and libration are irrelevant
to planning for the LCROSS impact. I meant only to reiterate my
perhaps too often made comment that the "age of the Moon" (understood
by most to mean the number of days since the most recent New Moon) and
the percent illumination of the Moon as a whole are poor predictors of
when lighting conditions at a particular point on the Moon will be
similar.

Likewise, I hope my frequent mention of "sun angles" has not led
people to expect a one-to-one relation between those and the
brightness of the features seen at the points where the sun angle is
computed. Over most of the Moon, the sun angle calculated by LTVT is
useful predictor of repeat lighting conditions. As a reference
direction, it uses somewhat arbitrarily the horizontal surface of an
imaginary spherical Moon. It changes continuously and gradually over
the surface of the sphere, without consideration of the real terrain.
When (and if) the sun angle and azimuth repeat at a particular
longitude and latitude, the lighting there will be exactly the same;
but the number by itself does not tell whether that lighting will be
bright, dark, or in between. That depends on the local and
surrounding topography. Obviously if, at that sun angle and azimuth,
surrounding features cast a shadow over the point of interest, the
surface there will be dark. If, on the other hand, it is being struck
by the Sun's rays, the brightness we perceive will be determined by
the intrinsic reflectivity of the surface element and by how the local
surface is tilted with respect to the incoming rays and to our line of
sight. None of those parameters are displayed by LTVT because it has
no idea how the surface may be tilted, or what its properties may
be.

-- Jim


P.S.: I am still curious if your Meade DSI Pro One images need an
adjustment in aspect ratio to match other images? Your August 9
image:

http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090809_1123UT/20080809_1123UT_OPW111d52mN40d46mKAF0_SP.jpg

for example, seemed to show horizontal video-like scan lines. I
cannot see those lines in the August 11 image:

http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090811_0937UT/20090811_0937UT_OPW111d52mN40d46mKAF0_SP.jpg

yet the short side of the rectangular frame still seemed to need to be
stretched by a factor of about 4/3 to match Chris' image taken the
same night with his Nikon D300 DSLR. I am wondering if 4/3 is the
right number, for it appeared to be slightly too strong a stretch.


On Aug 16, 11:01 pm, "canopu...@yahoo.com" <canopu...@yahoo.com>
wrote:

> http://members.csolutions.net/fisherka/astronote/observed/LCROSS/2009...

> ...
>
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