AIPS HELP file for IMCENTER in 31DEC22
As of Tue May 17 23:35:18 2022
IMCENTER: Verb to find coordinates of sub-image centroid
INNAME Image name (name)
INCLASS Image name (class)
INSEQ 0.0 9999.0 Image name (seq. #)
INDISK 0.0 9.0 Disk drive #
BLC -1.0 Bottom left pixel
TRC 0.0 Top right pixel
FLUX Include pixels > FLUX
PRTLEV -2.0 10.0 <= -1 => no display results
@ Output adverbs
PIXXY @ Fitted (X,Y,...) pixel of
COORDINA @ Coordinates at pixel
ERROR @ > 0 => fit failed, else okay
Use: IMCENTER reads a piece of an image and finds the
INNAME......Image name(name). Standard defaults.
INCLASS.....Image name(class). Standard defaults.
INSEQ.......Image name(seq. #). 0 => highest.
INDISK......Disk drive # of image. 0 => any.
BLC.........Bottom left corner. If BLC = -1,r then do a circle of
radius r pixels centered on the TRC position
TRC.........Top right corner or center of circle in pixels
FLUX........If FLUX > 0, ignore all image values below FLUX. If
FLUX < 0, ignore all image values less than -FLUX in
absolute value. WARNING: if FLUX is set too low, the
centroid can be pulled away from the obvious position by
more than one might first expect.
PRTLEV......Print level: if <= -1, then do not put result info
in message file, otherwise do a coordinate display
PIXXY.......Fitted (X,Y,...) position of centroid
COORDINA....The X and Y coordinates are found as:
Xpos = abs(CO(1)) + abs(CO(2))/60 + abs(CO(3))/3600
if any of CO(1), CO(2), CO(3) < 0: Xpos = -Xpos
Ypos = abs(CO(4)) + abs(CO(5))/60 + abs(CO(6))/3600
if any of CO(4), CO(5), CO(6) < 0: Ypos = -Ypos
Note that, although these are most suited to RA, Dec in
sexagesimal notation, they can be used for any type of
coordinate. The units are standard FITS units (e.g
degrees, m/sec, Hz, sec, etc.) except that right
ascensions are in hours of time.
ERROR.......If the verb is not aborted for error, but the fit
fails (all pixels < FLUX), ERROR will be TRUE (1), else
it will be FALSE (-1). Used to detect failures without
stopping a procedure or RUN file.