CRIRES User Manual
Doc. Number: ESO-254264
Doc. Version: P109.4
Issued on:
2021-12-01
Page:
61 of 99
Document Classification: ESO Internal Use [Confidential for Non-ESO Staff]
6.3.1 Target details
In the
p2/Target tab
, the user is expected to provide the following TARGET details
6
:
·
Right Ascension/Declination / Equinox / Epoch
(TSF:
TEL.TARG.ALPHA, TEL.TARG.DELTA,
TEL.TARG.EQUINOX, TEL.TARG.EPOCH
) are the of the science target and the equinox for which
these coordinates correspond to. In case of multiple objects in the slit or of extended objects,
these coordinates correspond to the telescope preset and acquisition. Target coordinates
should be as accurate as possible. VLT absolute pointing accuracy is better than 3” rms.
·
Proper Motion Right Ascension/Declination
(TSF:
TEL.TARG.PMA, TEL.TARG.PMD
) are the
target proper motion values in RA and DEC and specified in units of ‘’/year. If they are
different from 0, the
Epoch
, (TSF:
TEL.TARG.EPOCH
), at which the coordinates were valid
should be given.
·
Differential
Right
Ascension/Declination
(TSF:
TEL.TARG.ADDVELALPHA,
TEL.TARG.ADDVELDELTA
) are the target additional velocities in α,δ and in units of
arcsec/second. For solar system objects, the coordinates should be the J2000 ICRF,
astrometric coordinates. In particular, the user should not provide the apparent coordinates
Note: the differential velocities for moving targets are to be specified directly in the
ephemerids PAF file (§ 6.8).
6.3.2 Optional - Telescope Guide Star (VLT-GS) details
In the following, we describe all parameters present in the
acquisition templates
that the
user is requested to define according to the selected instrument mode. The Telescope
Guide Star details are optional, and users are encouraged to leave the VLT-GS selection
to the telescope operator.
·
Telescope guide star selection
(TSF:
TEL.AG.GUIDESTAR
): if set to CATALOGUE, then
the Telescope Control System will semi-automatically search for telescope guide stars
which can be selected by the telescope operator. However, if the user wishes to provide the
coordinates of the telescope guide star, then
TEL.AG.GUIDESTAR
should be set to
SETUPFILE. However,
users are encouraged to leave the VLT-GS selection to the
telescope operator
(
TEL.AG.GUIDESTAR
=CATALOGUE), as they are in the best position to
pick the most suitable stars for the real-time conditions.
·
RA/DEC of telescope guide star
(TSF:
TEL.GS1.ALPHA, TEL.GS1.DELTA
) are only relevant
if
TEL.AG.GUIDESTAR
= SETUPFILE. These parameters correspond to the J2000 coordinates,
epoch of the observations, of the telescope guide star. Otherwise, both parameters should
be kept to their default values (i.e., 00:00:00). Ideally, the VLT-GS should have R-band
magnitude in the range 11 to 13, located between 2’ and 11’ from the target and possibly
be isolated. Fainter GS may only work in good conditions.
6
For observations of moving object, the target position and motion are provided through tracking
table, see dedicated section (§ 6.8)
