NASA IRTF (3m telescope) mosaic of S polar region with craters identified

[Dr. Diane Wooden]

Dear Members,
I am introducing myself as a professional astronomer and infrared
spectroscopist who is developing methods to point and guide on the
Moon to assist observers at larger telescopes in their successful
effort of obtaining images and spectra of the LCROSS impact event. I
am member of the LCROSS Science Team.

I have uploaded a mosaic of the S polar region taken with the SpeX
Guidedog slit-viewing imager (irtfweb.ifa.hawaii.edu/~spex/) on the
NASA IRTF 3 m telescope on Mauna Kea. The images were taken on 2008
Nov 07 08:00 UT. The centers of craters are identified with lunar
coordinates, and those coordinates are probably accurate to about
+/-0.2 deg. Each image was 0.24 sec, has a plate scale of 0.15 arc
seconds per pixel, and were taken through a 1.5% wide narrow band
filter centered on 2.294 micron. The full array is approximately 60
arc sec by 60 arc sec.

I hope that this image mosaic will help observers to practice pointing
the region of the S pole where Faustini crater lies. This is a
location within Faustini crater that is favorable for having excess
hydrogen, and represents one of a number of possible LCROSS impact
locations.

I will post another email describing how to obtain Right Ascension,
Declination of lunar geographic coordinates. Search for Subject:
Lunar Crater Ephemerides with Horizons.

Cheers, Dr. Diane Wooden (NASA Ames, LCROSS Science Team Member)

[Jim Mosher]

Great to meet you, Dr. Wooden. Thanks for sharing the IRTF image from
Nov 7th, and I look forward to your instructions on converting "lunar
geographic coordinates" to Right Ascension and Declination. Am I
correct in assuming they will appear on this forum? Or are we being
distributed via some other e-mail list?

Not being a professional astronomer I am also a bit uncertain about
the notation "g:" on your IRTF image mosaic. Does this mean
"geographic coordinates" and do they differ in some way from the usual
selenographic coordinates? I notice you have modified the values for
Schomberger C and G and Malapert K from the ones that appear in the
IAU Planetary Gazetteer. I assume this is intentional, but it seems
curious that Malapert K and Schomberger G have been given the same
values when they are indicated as being at different positions.

Also, what is the source of these numbers? Except possibly for
Faustini, they seem farther from the "correct" positions indicated in
the USGS Warped Clementine Basemap:

http://webgis.wr.usgs.gov/pigwad/down/moon_warp_clementine_750nm_basemap.htm

than do the values already appearing in the IAU Planetary Gazetteer:

http://planetarynames.wr.usgs.gov/

The approximate values I read from the USGS ULCN2005 Warped Basemap
are:

Faustini : lon = 85.26 lat= -87.18 diam = 42 km
Schomberger : lon = 24.73 lat= -76.66 diam = 85 km
Schomberger C : lon = 15.20 lat= -77.18 diam = 42 km
Schomberger G : lon = 7.23 lat= -77.02 diam = 17 km
Malapert K : lon = 5.88 lat= -78.67 diam = 36 km
unnamed crater between Schomberger C and Malapert K :
lon = 10.91 lat= -78.11 diam = 40 km

Do you have some reason to believe these are incorrect?

(the longitudes, of course, become increasingly ill-determined for
features close to the pole, and Faustini is only vaguely defined in
the Clementine mosaic)

Also, although the flier says you need 0.5 arc-sec pointing, it looks
like the IRTF telescope only detects craters to about 3-4 km diameter
(i.e., about 2 arc-sec). Is this typical? Or does the slit-viewing
imager give an incorrect impression of its performance?

Also, is it possible to rotate the IRTF slit with respect to the lunar
axis? I believe you will have a much greater chance of success if you
can orient the slit along a radial line. As the Moon's librations
change, the radial distances between landmarks varies depending on
their relative heights (which may be poorly known). Their positions
in azimuth (relative to the lunar polar axis) are little affected by
height differences. Hence you can guess where a feature will be in
azimuth much better than in radius.

Finally, I seem to recall that earlier this year NASA/JPL announced a
soon-to-be-released detailed three-dimensional Goldstone radar model
of the lunar south polar region, and perhaps Kaguya and Chang'e-1 are
working on similar things. By the time of the LCROSS impact,
shouldn't it be possible to predict the expected relationships between
lunar surface features as seen from any site using these?

Thanks again,

-- Jim

[Dr. Diane Wooden]

Dear Jim,
Thank you for the links to coordinates. I will check these links and
get back to you.
I obtained the coordinates by working the the orbital dynamicist and
picked the coordinates by eye off a 3-d rendition of the moon - and
hence they could be in error.

I appreciate the links! This may help in our pointing exercise. I
should be able to confirm before Thursday 2008-Dec-05,06,07, when we
have more telescope time.
Cheers, Dr. Diane Wooden

[cano...@yahoo.com]

Jim,

I have added file LCROSS20081206FaustiniLocator_kaf.jpg to the files
section. The file takes Dr. Wooden's image, calibrates it to your
LTVT lunar planetarium program, using LTVT displays the lettered
crater names over the top of the image, and then outputs it with the
geometry for 12/6/2008 3UT from my OP at 42N 111W.

This annotated image may help persons intending to image next week to
zero in on the target area using the traditional Rukl Atlas
resource.

With this orientation, I'm assuming the August 2009 impact is intended
to send an ejecta blanket up to be contrasted against the background
sky instead of against the brighter lunar terrain.

While I intend to set up a scope, the western U.S. weather pattern has
changed into its winter mode. I'm remaining cautiously optimistic
that this will not a cloud out for my o.p.

- Kurt

On Nov 27, 11:40 am, Jim Mosher <jimmos...@gmail.com> wrote:
> Great to meet you, Dr. Wooden.  Thanks for sharing the IRTF image from
> Nov 7th, and I look forward to your instructions on converting "lunar
> geographic coordinates" to Right Ascension and Declination.  Am I
> correct in assuming they will appear on this forum?  Or are we being
> distributed via some other e-mail list?

<snip>

[Jim Mosher]

Good work, Kurt!

I see you have only added labels for the craters that are labeled on
Rükl's hand-drawn zero libration view in Sheet 73 of his book:

http://the-moon.wikispaces.com/Rukl

(which, of course, didn't include Faustini, since it wasn't named at
that time). That should certainly be helpful to those who use Rükl's
maps for pointing.

Lest this cause confusion, there are many other small craters in this
area that have official IAU names, such as the smallest of Dr.
Wooden's five ellipses, which is 17-km diameter Schomberger G; and
some that have never had names, such as the dashed one she draws
between "K" and "C".

For a more complete list of named features in this area, click on the
link to the SE lettered craters quadrant map at:

http://the-moon.wikispaces.com/Rukl+73

The official position of Faustini is essentially on the limb in that
zero libration view, with its center marked by a blue dot just to the
left of the "F" in its name.

Having names does not, of course, guarantee that these are the best
landmarks for a particular lighting and resolution.

I have a fairly large collection of amateur south pole images
collected from the internet, many with higher resolution than the
current IRTF image. I'll try to look through them and see if any have
a suitable lighting and libration for constructing finder charts for
Dec. 6-8; and what seem like they will be the clearest landmarks at
that time. It would seem Faustini will not actually be recognizable
from Earth on those dates, but I guess one can put a dot at the limb
and say "here's where its center would be if we could see it."

It's still unclear to me if the north pole targets are of interest on
those dates, or even exactly what the intended targets ("Crater A" and
"Crater F") are. My collection of north polar images is much smaller.

-- Jim


On Nov 28, 11:01 pm, "canopu...@yahoo.com" <canopu...@yahoo.com>
wrote:

[Jim Mosher]

Kurt-

Please ignore my comment that "Faustini will not actually be
recognizable from Earth" on Dec. 6-8. I must have been thinking of
the October 9-11 campaign, where the objective seemed to be place the
center of Faustini exactly on the limb.

The librations on Dec. 6 will actually be very similar to those in the
recent LPOD Photo Gallery image by Carmelo Zannelli:

http://lpod.org/coppermine/displayimage.php?pos=-3723

Faustini is completely onto the visible disk under such conditions and
readily visible in the photo -- between pixels (87,97) and (183,106)
-- although probably considerably more challenging to visual
observers. The lighting will be even more similar by Dec. 8, when
Faustini will be even more onto the disk.

-- Jim