AIPS HELP file for INDXH in 31DEC21
As of Wed May 5 16:16:07 2021
INDXH: Task to index a uv data base.
INNAME Input UV file name (name)
INCLASS Input UV file name (class)
INSEQ 0.0 9999.0 Input UV file name (seq. #)
INDISK 0.0 9.0 Input UV file disk unit #
CPARM -1.0 9999.0 1=> max. time gap (min).
0 => 10 min
2=> max scan length (min).
0 => 60 min
3=> CL/CS entry interval in
minutes. 0 => 5 min,
< 0 => don't create a
4=> VLBA only: recalculate
CL entry group delays
using IM table data.
0 => No recalculation,
1 => Recalculate delays.
5=> single-dish only: maximum
in data set (if no AN)
Use: Creates an index (NX) table and indexes the uv data file. A
maximum time gap and a maximum scan length may be specified.
If no CL (CS for single-dish data) table is present, an empty one
is (optionally) created. Data must be in T* order and may be in
single-source or multi-source format. The NX table is used to
speed access to uv data sets by giving offsets into the file for
time ranges, source numbers, and the like. CL and CS tables,
version 1, are the basis for interferometer and single-dish
calibration. Usually they are created as the data are read in
(for the VLA with FILLM, for the VLBA with FITLD, and for some
single-dish data sets with SD2UV) and should not be replaced. If
they are lost or were never created (i.e. OTFUV in OTF 12m data),
then INDXH may be used to create them if they are needed.
INNAME.....Input UV file name (name). Standard defaults.
INCLASS....Input UV file name (class). Standard defaults.
INSEQ......Input UV file name (seq. #). 0 => highest.
INDISK.....Disk drive # of input UV file. 0 => any.
CPARM......CPARM(1) = max. gap in data in minutes. If a gap longer
than CPARM(1) is found, a new index record will be
started. 0 => 10 min.
CPARM(2) = max. length (in minutes) of a scan. If an
uninterrupted section of data on the same source longer
than CPARM(2) is found, a new index record will be
started. 0 => 60 min. [For single-dish data, a "SCAN"
random parameter, if present, will also be used to
determine scan boundaries. In this case, set CPARM(2)
to a high value unless you want to subdivide scans.]
CPARM(3) = interval of CL (CS for single-dish) table
entries in minutes. If there are no CL/CS tables
associated with the data a new one will be created with
null (1's and 0's) entries. 0 => 5 min.
If CPARM(3) < 0, then a new CL or CS table will not be
CPARM(4) = VLBA-only delay recalculation option. When
recreating a CL table, the geometric group delays used
by the VLBA correlator are recalculated using
information from the IM table.
0 => No recalculation, 1 => recalculate delays.
CPARM(5) = single-dish only: the maimum antenna or beam
number actually in the data set. This is used to cover
up for absent antenna (AN) tables only.