README web version of /home/usg/OPS/MTS/readme_xml/readme_74029400
Principal Investigator Email Address
Estimated Total Execution Time (hours, including overheads)
General Description
This is a spectroscopic monitoring program of brown dwarfs over the range
0.95-1.65um. For each of the six targets, the spectrograph slit is aligned to include
both the target and a nearby reference star. We observe by dithering these two objects
along the slit between two positions continuously for about 4 hours.
A single science template takes three exposures at each of two positions and then
returns to the nominal position. The same integration times are used for all objects.
A single OB consists of an acqusition followed by six science templates and takes
55 mins to execute. (The only exception are OBs with suffix ".d" suffix, which have
eight science templates, so take 71 mins).
It is very important that all the OBs for a single target are executed in a single
contiguous sequence with as little gap between them as possible.
For each target there are four OBs, with suffices ".a", ".b", ".c" and ".d", which
should be executed in this order. All four of these include acquisition templates,
but those in b-d should not be used (see "Special Execution Requirements").
Waiver Requests
Critical Observing Condition Constraints
Time-Critical Aspects
Special Execution Requirements
This is a monitoring program so it is very important that all the OBs
for a single target are executed in a single contiguous sequence with as litle gap
between them as possible. For each target there are four OBs, with suffices ".a",
".b", ".c" and ".d", which should be executed in this order. These take about 4
hours to execute per target.
The rotation angle (position angle of slit, increasing counter-clockwise from North)
has been set to an approximate value to include both target and reference in the
slit.
An exact value cannot be given because most targets have unknown (but large) proper
motions.
During the initial acqusition (i.e. in the ".a" OB), the observer should therefore
manually adjust the position angle and the telescope pointing such that both stars
lie EXACTLY in the slit. It is important to get this right, so please take time
to do this carefully.
The telescope should then be pointed such that the center of the field-of-view is
roughly in the middle between the target and reference and not on the target. (The
reference star for 2M1555-09 is approx 143" East of the target, so an initial offset
may be necessary to even see this in the acqusition image.)
After completion of the ".a" OB, please take out the grism and re-check the telescope
pointing and slit alignment. In my experience with SOFI it is often necessary to
make small adjustments to re-center the stars in the slit. Then run the ".b" macro
but WITHOUT running the acqusition template, as the pointing has just been optimized.
Repeate this (taking out grism to check pointing and skipping the acquisition template)
for ".c" and "d.".
A guide star should be used for all the observations.
If conditions are such that a 4 hour window
is unlikely to be available (e.g. at the end of the night), or if there are small
gaps due to instrument problems, then it would be acceptable to get a run which
gets only 3.5 hours on target, e.g. stopping in the middle of OB ".d". The extra
time can then be used to extend the observing on another object (e.g. by adding
more templates in the ".d" OB).
Special Calibration Information
I assume that you will observe at least one telluric standard (e.g. rapidly
rotating F star or an OB star) each night with my observational set-up.
Flats, arcs and darks can be done during the day, of course, so I assume that they
do not count as part of my OPC allocation.
I DO need dark frames for the data reduction (for estimating the sky noise contribution).
One set of OBs have been provided. If possible, please run them on each day that
my OBs are executed.
Flat fielding is very critical for this project. For this reason I would like to
obtain
both normal, or "external" dome flats (illumination of a screen in the dome) and
Nasmyth dome flat, i.e. illumination by an internal lamp. (I did both in visitor
mode in Feb. 2004). There does not seem to be a way to specify which type of lamp
to use with the calibration template, so I have just provided a single domeflats
OB. However, please run it with both "internal" and "external" flats. Please also
do these flat fields every day that my OBs are run.
The wavelength calibration with the arc lamps should be done every day that my OBs
are run.
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 ?
Last creation of page: Tue Oct 6 15:40:06 2009
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