Purpose
Take a series of exposures required for the LRIS monthly
throughput check using the current grating.
Usage
observe_flux_standard
Arguments
none
Procedure
- verifies that the telescope is pointed to a known LRIS
flux standard star by checking DCS keyword TARGNAME
- check the current grating and build appropriate exposure list
- save current LRIS configuration
- check that SKYPA is correct for this star
- set pointing origin to SLITB
- configure for slitless spectroscopy
- acquire exposures
- restore configuration
Restrictions
- before starting the script, you must set the SKYPA to the
correct value for the star you plan to observe. See the following
table
- a grating must be in place when the script is started
Valid targets
Starname PA
-------- --
G191B2B 0
HZ44 90
BD+28deg4211 90
Feige34 90
Feige110 90
Exit values
0 = normal completion
1 = wrong number of arguments
2 = current star is not a valid LRIS flux standard
3 = no exposures defined for current grating
4 = number of filters and wavelengths don't match
5 = SKYPA is wrong
Note
SKYPA must currently be set manually prior to running the script,
since it is not possible currently to ensure that it can be set
automatically to a value not near the limits.
Example
1) To acquire exposures on the star G191B2B with the 600/7500 grating
- point the telescope to G191B2B (any pointing origin)
- set the SKYPA to the 0 deg (see table above)
- move the 600/7500 grating into position
execute the command
observe_flux_standard
The script will acquire 3x30s exposures on the red side and 3x30s in blue