Use Case:
SetupSingleField
Starting from user's scientific input, determine all parameters necessary
to perform single field interferometric observations.
Role(s)/Actor(s):
Primary: Observer
Secondary: Line Catalog, Source Catalog, Array Configuration Catalog
Priority:
Major
Performance:
seconds.
Frequency:
100/hour
Preconditions:
-
...
Basic
Course:
-
User specifies
-
field name.
-
coordinate system.
-
field center coordinates (either by absolute coordinates or offsets from
a direction specified by its absolute coordinates).
-
System checks the declination.
Exception Course: The source is not observable from the ALMA
site.
-
User specifies
-
desired synthesized beam size
-
field width
-
User specifies
-
number of IF bands
-
Line names; the frequencies are obtained from the line catalog
Alternate Course: User enters line name and line frequencies
Alternate Course: User enters continuum frequency
-
For line observations, the user specifies
-
center velocities
-
velocity reference systems
-
velocity bandwidths
-
velocity resolutions
Alternate Course: for continuum, the user specifies
-
frequency bandwidths
-
frequency resolutions
-
User specifies phase calibrator choice policy (closest with given minimum
flux, strongest with maximum distance, calibrator named explicitly from
the instrument catalog)
-
User specifies phase calibration observing frequency and phase rms goal
on calibrators at target observing frequency, and whether the radiometric
phase correction is to be used
-
User specifies that the integration times of the phase calibration cycle
are optimally determined at run time from measured phase rms
Alternate Course: the integration times are given explicitly
-
User specifies the parameters of bandpass calibration:
-
the calibrator is to be chosen at observing time
Alternate Course: the calibrator is explicitly specified
-
the goal in rms phase is specified
-
User specifies the performance goals: total integration time and/or final
rms
-
The system evaluates the proposed setup:
-
The field size is compared to the primary beamwidth at the observing frequency.
Alternate Course: if larger a mosaic observation is suggested
-
beam information is computed (ellipticity, actual size)
-
the system computes maximum and minimum baseline lengths needed, and makes
some comments about configuration availability (TBD).
-
map cell size and number of pixels are computed.
-
the correlator setup is explicitly computed from the spectral information.
Warnings are given if the spectral coverage is affected by Doppler effect
variations.
-
proposes splitting into SBs based on observatory policy (max. SB length)
-
The User may either refine its input parameters, modify the deduced setup
parameters, or accept the system provided values.
Issues to be Determined
or Resolved ...
Notes: Coordinates may be also graphically determined from a
user provided map or image.
Last modified: 2000/07/28 R. Lucas, 2000/11/10 D. Muders