Preparing LUCIFER Scripts
While reviewing some of the LUCIFER SDT-scripts, we (Ian & Jochen)
found a couple of common mistakes:
- Absolute offsets are based on a coordinate system derived from the initial
pointing of the telescope.\xA0 If changes have been made to the pointing (for
example, to move an object into the slit), they will be lost when an absolute
offset is sent.\xA0 This is why nodding an object along the slit or performing
offset guiding from a nearby reference object should always be done with
- Saturation should be avoided.\xA0 When setting exposure times for acquisition
scripts, make sure there are no bright stars in the target field.\xA0 If there
are, use a NB filter (as mentioned above) and set the exposure time for the
acquisition script accordingly to avoid saturation (use the ETC to determine
an appropriate time).
- Make shure that your guides star is sufficiently away from your target,
otherwise vignetting of the LUCIFER field by the guideprobe can be a serious
problem (cf Fig. 10 in the LUCIFER users manual).
- Note that LUCIFER and the AGw are bolted together, any rotation of
LUCIFER on the sky comes with a rotation of the useful field
for a guide star on the sky.
- Do not use a blind filter in the acquisition script.
- Observations in parallactic mode are normally not necessary in H+K
(differential refraction is very-low). Observations in parallactic mode can
only be carried out in Telescope_mode = track (i.e,
without a guide star).
- In your spectroscopic script, no telescope_setup and no acquisition is
required (both are already done in the acquisition script).
- Spectroscopic scripts need to be split into an acquisition script
and a science script. The general outline is (thanks Dave):
an acquisition script:
filter for spectroscopy (or NB filter for bright sources)
desired spectroscopic mask in fpu
coords for source and guide star
short exposure in READOUT_SETUP (3x10s integrated)
OBSERVING_SETUP ends with ACQUISITION=0.0 0.0
and then a spectroscopic script:
desired slit to mask_in_fpu
NO TELESCOPE_SETUP section (already done in acquisition)
NO ACQUISITION in the science script (already done in acq.)
Relative OFFSETS along slit, exposure taken at each offset
- DIT refers to the detector integration time, NDIT to the number of DITs
(which can be saved individually, as cube or integrated) and
NEXPO to how often NDIT time DIT will be executed at any given position.
- Note that you need to specify the duration the lamps should be turned on
for your arcs/flatfields. Take into account the readout-time (2sec).
E.g. for a 1 arc with 10sec, the lamp should be 1 * 10sec + 1 *2sec
+5 extra sec = 20sec on (e.g. Ar 20).
- Observation should always be taken in ACTIVE mode, even for standard and telluric stars
- 08 Dec 2009