AIPS HELP file for MOMFT in 31DEC25
As of Thu Jan 23 21:02:30 2025
MOMFT: Task to calculate moments of a component
INPUTS
INNAME Image name (name)
INCLASS Image name (class)
INSEQ 0.0 9999.0 Image name (seq. #)
INDISK 0.0 9.0 Image disk unit #
IN2NAME Beam image name (name)
IN2CLASS Beam image name (class)
IN2SEQ 0.0 9999.0 Beam image name (seq. #)
IN2DISK 0.0 9.0 Beam image disk unit #
BLC 0.0 4096. Bottom left corner of image
0=>entire image
TRC 0.0 4096. Top right corner of images
0=>entire image
FLUX Flux Noise level to exclude
OUTTEXT
Name of output log file,
No output to file if blank
HELP SECTION
MOMFT
Type: Task
Use: MOMFT determines the parameters of a component by calculating
the zero, first and second moments associated with a part of an
image. The moments of the image are compared with that of the
beam to obtain the gaussian sizes of the component.
WARNING: This task is unreliable!!!!!!!
Adverbs:
INNAME......Image name (name). Standard defaults.
INCLASS.....Image name (class). Standard defaults.
INSEQ.......Image name (seq. #). 0 => highest.
INDISK......Disk drive # for the Image. 0 => any.
IN2NAME.....Beam image name (name). Standard except all
blank => use actual INNAME.
IN2CLASS....Beam image name (class). Standard except all
blank => use 'IBEM '.
IN2SEQ......Beam image name (seq. #). 0 => actual INSEQ.
IN2DISK.....Disk drive # for the Beam image. 0 => INDISK.
BLC.........The bottom left-hand pixel in the image
corresponding to the bottom left-hand corner of
the component. (0,0) means (1,1).
TRC.........The top right-hand pixel of the image
corresponding to the top right-hand corner of the
component. (0,0) means use top right hand corner
of the map.
FLUX........PIXELS with brightness less that FLUX are excluded
from moment calculations
OUTTEXT.....Output file to log measurements for later user
processing. File created if it does not exist
and appended to if it already exists. Nothing is
is written to a file if the name is blank. File
name should contain directory and file parts, i.e,
"LOCAL:IMEAN.OUT" or "RUNFIL:IMPORTANT.POINTS"
EXPLAIN SECTION
MOMFT: Task makes a rough measurement of the size and shape
of a source in the input image.
DOCUMENTOR: G. Langston, NRAO
RELATED PROGRAMS: IMEAN, IMFIT, JMFIT and AIPS verbs IMSTAT and
MAXFIT
PURPOSE
MOMFT is designed to produce a measure of the source size
that is relatively simple (and quick). If the input pixels
used in the moment fits are limited to only those pixels that
are brighter than a few sigma above the RMS noise level,
the results are much more reliable.
The input limiting FLUX should be set to roughly 3 times the
rms noise. Note that pixels with flux more negative than
-FLUX are include in the MOMent FiTs.