README web version of /home/usg/OPS/MTS/readme_xml/readme_80505300
Principal Investigator Email Address
Estimated Total Execution Time (hours, including overheads)
General Description
The goal of this DDT is to observe simultaneously on UT1 with CRIRES and
on UT2 with UVES+FORS1 the bright comet 8P/Tuttle. Those observations will be done
on two different nigths (the closest the 2 nights are in time, the best it is).
CRIRES is run(A), UVES is run(B) and FORS1 is run(C).
The observations on both telescopes need to be coordinated (both telescopes available).
The observation will last for 4 hours on each telescope (in parallel) starting from
beginning of astronomical twilight (the comet is setting).
As the comet is also getting fainter, the soonest the observation are done, the
better it is (before Feb 10 in any case).
CLR or PHO weather and low humidity is important for the success of the observations.
run (A) : On UT1 there are 6 OBs to execute consecutively each night : 2 science
OBs (2 different settings A and B) of 1.5h + 3 telluric (before, between with the
2 settings and after) and 1 flux std star (with both settings). The order of execution
and other info are given in special execution requierements.
run (B) : On UT2 there are 2 OBs to execute consecutively each night with UVES :
one science OB with DIC#1 (note that the blue setting is non std with 348nm central
wavelength) and one science OB with the DIC#2.
run (C) : After the 2 UVES OBs are done there in each night one FORS1 LSS OBs with
several offsets to executed + one "sky" OB to take a spectrum of the sky 30 min
away in RA.
NB : As the target is a fast moving object it is of course needed to update the
coordinates and diff velocities in the OB before execution (using 5min by 5min ephemeris
provided).
This general description is the same for the 3 runs but the other subpanels (for
instance special calibrations, special execution requierements) are specific for
each instrument.
Waiver Requests
A waiver request was approved for CRIRES on Jan 25 in order to :
- use the 3 free reference wavelengths : 2935.5 nm, 3042.6 nm and 3335.8 nm
- in order to have long OBs (1h30) and execute them consecutively (total sequence
= 4 hours)
- skip wave template and let only flat template at the end of the OB
Critical Observing Condition Constraints
Time-Critical Aspects
This run is simultaneous with run(B) and (C) on UT2!
Both telescopes need to be available in service mode simultaneously for 4 hours
in a row and since the beginning of the night. This needs to be coordinated between
each telescope operators. But no need to start the OBs exactly at the same time
(15 min delay is fine - CRIRES might start earlier in twilight).
As the comet is also getting fainter, the soonest the observation are done, the
better it is (before Feb 10 in any case).
The comet is setting so the OBs need to be started directly at the beginning of
the night to have the 4 hours window.
The OBs can be started as soon as a guide star is acquired.
Special Execution Requirements
There are 6 OBs with CRIRES each night and the order of execution is the
following :
Night 1
---------
Programme Id Id | OB Name Exposure Time Execution Time
-------------- -------------------------------- -------------
280.C-5053(A) Telluric_n1_A 00:00:40.000 00:12:45.000
280.C-5053(A) MOV_8P_n1_A 01:00:00.000 01:32:42.000
280.C-5053(A) Telluric_n1_AB 00:01:20.000 00:15:35.000
280.C-5053(A) MOV_8P_n1_B 01:00:00.000 01:32:42.000
280.C-5053(A) Telluric_n1_B 00:00:40.000 00:12:45.000
280.C-5053(A) Flux_n1_BA 00:01:20.000 00:15:35.000
Night2
------
280.C-5053(A) Telluric_n2_A 00:00:40.000 00:12:45.000
280.C-5053(A) MOV_8P_n2_A 01:00:00.000 01:32:42.000
280.C-5053(A) Telluric_n2_AB 00:01:20.000 00:15:35.000
280.C-5053(A) MOV_8P_n2_B 01:00:00.000 01:32:42.000
280.C-5053(A) Telluric_n2_B 00:00:40.000 00:12:45.000
280.C-5053(A) Flux_n2_BA 00:01:20.000 00:15:35.000
The names of the OBs are self explanatory with n1 or n2 for night1 or 2, with A
and B the settings, with Telluric or Flux for the telluric or flux std stars. AB
or BA means there are 2 wave setups in the OB.
Fast moving target !
-------------------
The coordinates *and* the differential tracking rates have to be to be updated in
the OBs before execution. 2 min step ephemeris have been provided. The position
angle is also given in the last column and needs to be updated in the acquisition
template (close to 75 deg) once per night.
Be carreful with the change of date in UT ! Few minutes after the night starts there
is a change of date in UT.
Dont use the secondary guiding with CRIRES on the comet. It was not working and
producing problems during previous attempts.
Please check that the comet stays in the narrow slit. If it is moving out rapidly
there is a problem (probably error in the diff tracking rates) It would be good
to update the diff tracking rates for the 2d OB (that can be done directly and in
any time on the telescope panel with the help of the TIO) because it is changing
with time.
Choice of guide star
-------------------
Warn the TiO about the choice of the guide star, to not take it too close to the
center of the field of view neither to close to the edge. The comet is moving mostly
towards the south so a good GS would be to the South of the field.
AO and slit width
-----------------
With the seeing request of 1.2" we hope AO will work as it was tested before on
the same comet. In this case the chosen slit width of 0.2" is fine. In case it is
not possible to close the loop we request to open the slit to 0.4" (idem for the
telluric of course).
Skip Wave template
-------------------
We have attached in each science OB a wave and a flat template. In fact we are only
interested by the flat so please skip the wave (it is not possible anymore to put
the flat template alone).
Special Calibration Information
We have provided for each night (n1 and n2) specific OBs to observe :
- Telluric stars :
first telluric asap in the evening twilight before the first science OB (setting
A),
then after the 1rst science OB a telluric with setting A and also the next setting
B,
and finally after the end of the 2d science OB with wave setting B.
We put dummy coordinates (close to the comet) for the telluric OBs so the operator
can chose the best telluric for a given night (the comet is moving fast from night
to night we would then need to provide many tellurics). Hot dwarfs of subdwarfs
stars are ok. DIT of 1O to 30 sec for K <=6.6 is ok.
- Flux std star :
At the end of each observing session (after the last telluric), flux std star 30
Monoceros needs to be observed in the 2 reference wavelengths with a 1.0" slit.
ToO Information
ToO Activators List
Do the README file and the instrument comments of the telluric stars
OBs include the required S/N/pixel of the spectrum of the telluric star, its spectral
type and allowed spectral range?
Do any OBs include wavelength or flatfield calibrations?
If you are observing Moving Targets, have you attached suitable ephemeris
files to your OBs?
If the slit viewer guide star is different from the target, are the RA
and DEC offsets accurate to within 0.05 arcsec and do they take into account the
relative proper motion between the two objects?
If you have preferences which OBs should be executed first for objects
at similar RA, did you make use of the User Priority field in the OBs?
Last creation of page: Tue Oct 6 15:40:22 2009
If you have comments, please contact usd-help@eso.org