README web version of /home/usg/OPS/MTS/readme_xml/readme_83503400
Principal Investigator Email Address
Estimated Total Execution Time (hours, including overheads)
General Description
This is a rather atypical program aiming to detect the descent stage of
the Apollo 11 Lunar Module on the Moon. The observation must take place at a very
specific time, when the Sun sets over the region and the descent module remains
as the only illuminated object in the area, appearing as a faint point source detached
from the terminator.
The PI will be most likely present at the telescope at the time of the observations.
The information provided here is intended to describe the procedure in case this
cannot happen in the end, and especially to enable a simulation of the observation
in advance to prove its technical feasibility.
The detailed description of the observation is provided in the Special Execution
Requirements section of this README form. The time window is provided in the Time-Critical
Aspects section.
THE OBSERVATION MUST TAKE PLACE ON THE NIGHT OF 10 TO 11 AUGUST 2009
Waiver Requests
Critical Observing Condition Constraints
Time-Critical Aspects
Observations can be done only on the night of 10 to 11 August, between
7:55 and 8:12 UT. However, given the necessary preparation time and the need to
decide on the wavefront reference feature, tune the AO setup, and modify the OB,
is is very advisable to start about one hour in advance of the predicted time.
Special Execution Requirements
The outline is as follows: the telescope must be first preset to a star
ahead of the Moon, which will be in gibbous waning phase on that night, to close
the active optics loop. Next, preset to the Moon and offset until encountering the
lunar terminator, where the telescope will need to be offset along it until finding
the region of interest. The finding chart 'luna_281007_zoom1.jpg' gives a full-disk
view of the Moon with the region of interest marked with a yellow square that represents
the field of view of NACO with the S54 camera. The images _zoom2 and _zoom3 are
progressive enlargements of that picture providing more detailed views of the surrounding
area, also with the NACO field indicated in the same way. The Moon phase will be
more advanced (this is, less illuminated) on the date of the observation, and the
features closer to the terminator in the finding charts will not be visible.
Near the field, the most prominent feature is the crater Sabine, located just
to the left of the yellow square in chart _zoom3. This crater will be well illuminated
a the time of the observation and is easy to recognize thanks to the presence of
the similarly sized crater Ritter, just to its east. Once identified, move by about
30" to the west to center the field in the area of interest. Probably within the
field but close to the edge is crater Moltke, the bright small crater near the bottom
right corner of chart _zoom3.
Once the field is identified, the chart "ground_label.jpg" should be the most
useful one to locate features. This chart contains an image obtained with a ground-based
telescope under very good seeing conditions and shows a number of features with
their names. Crater Aldrin should be the easiest to recognize at the time of the
observations, but it is too far to be used for wavefront sensing. Crater Sabine
C is a much better wavefront reference, being only 10" from the Apollo 11 landing
site, and it should be illuminated by grazing sunlight at the time of the observation.
However, at that time it should be considered if the unnamed crater next to Sabine
C to it south, which is only 8" from the landing site, can be used instead. The
nearest crater is the so-called Cat's paw, but this is a very shallow feature without
raised rims and it should become very faint or even disappear shortly before or
during the time-critical window, so it should not be used.
Once the wavefront reference feature has been chosen, the execution of the OB
can start. This contains a long series of 10s integrations in H with no offsets
in between, so as to avoid time-consuming telescope offsets during the time that
it takes the terminator to move from the lunar module to the horizon. Given the
faintness of the target, we need to integrate for as long as possible to gain depth.
Background subtraction will be achieved by using frames obtained after an offset
of the telescope toward the dark side right after the end of the observation. At
the data reduction stage, we will also experiment with differential subtraction
of frames taken early and late during the observation, so that the fringe area run
by the terminator can be subtracted from itself when it is illuminated and when
it is not. The DIT=10s is likely to produce saturation, and it should be reduced
accordingly based on the actual illumination of the field to the longest non-saturating
value before the observation starts.
The OB has indicated in it that storage of data cubes is switched off. This was
done in order to be able to check the OBs in, as data cubes are supported is visitor
mode only. However, the OB should be modified to tick this option on, as the quality
of the final reduction can be optimized if all individual frames are kept. Please
do not forget to do this change before starting the observation, as receiving only
one frame with the stack of 100 NDITs would render the observation useless.
Christophe Dumas has sent additional technical details regarding the observing
strategy. They should take precedence in case of conflict with the procedure outlined
here.
Special Calibration Information
ToO Information
ToO Activators List
Is this a Pre-imaging run ?
Pre-imaging Requirements
Source(s) of Pre-imaging
Pre-imaging sources not listed above
Do all your OBs comply with the instrument-specific requirements listed
on the instrument-specific Phase 2 web page ?
If this is a pre-imaging run, did you select PRE-IMAGING for the Observing
Category for each Observing Template ?
Do all your finding charts comply with both the general and instrument-specific
Phase 2 Web Pages ?
If you submitted OBs for standard stars, did you specify the magnitude
and spectral type of all standard stars in the OBs ?
Have you included OBs for any calibrations that you need but which are
not part of the Calibration Plan ?
If you are observing Moving Targets, have you attached suitable ephemeris
files to your OBs?
If you have preferences which OBs should be executed first, did you make
use of the User Priority field in the OBs ?
If this is a run that requires coordinated observations with other facilities,
did you give proper instructions in the Time-Critical Aspects Section ?
If you have PSF reference star OBs, do the names of those OBs begin with
PSF_ ?
If there are Finding Charts attached to your OBs, is the field-of-view
of at least one of these charts 2' x 2' (with clearly labelled field orientation)
?
Have you clearly marked and labelled your wavefront reference objects
R1, R2, R3, ... (as specified in the NAOS Preparation Software) on your Finding
Charts ?
Have you specified the magnitude of the brightest object in the field-of-view
for each OB ?
Are there objects in any of your fields (including standard stars) which
are brighter than the limits specified in the User Manual and on NACO web Pages
?
If the previous answer is yes, have you given a list of OBs and a justification
for the brightness limit violation in the general description field ?
Last creation of page: Tue Oct 6 15:40:31 2009
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