IRAF Help page for: CAMOFFSET

CAMOFFSET (Aug96)            	pipeline            CAMOFFSET (Aug96)

camoffset -- Calculate camera offset angles using COPIPE or
DRIFTSCAN results.

camoffset input


List of input V, M, or I images for which the camera offset
angle is to be determined.

drift_scan = no
Use Drift-Scan formuli only.

tables = "grasplib$SITES/"
Path to offset tables.

verbose = no
Verbose output to STDOUT.


camoffset uses the hour angle from the input image headers
(keyword: HA; units: radians) and empirical formula to determine
the camera offset angle. The calculated offset angle in degrees is
written into the image header as the value of the keyword OFFSET.

The GONG pipeline process COPIPE determines an internally consistent
set of equations (maximum 6 term power law) describing how the
camera offset angle changes with time at each site. The
coefficients for these equations are stored in STSDAS binary tables
located in tables. The table columns are:

gps_date CH*10 %10s "GPS Date"
n_coeff I %1d "No. of Coefficients"
c1 R %f ""
c2 R %f ""
c3 R %f ""
c4 R %f ""
c5 R %f ""
c6 R %f ""
drift_scan CH*2 %2s "PM Driftscan"

The column "drift_scan" is blank except for those dates where a
drift scan was taken, in which case the column contains "pm".

camoffset uses the value of the header keyword SITE to determine
ensure that the proper table is use. Accepted values of SITE are

tc ==> Tucson
bb ==> Big Bear
ml ==> Mauna Loa
le ==> Leamonth
ud ==> Udaipur
td ==> Teide
ct ==> CTIO

If drift_scan=yes, the coefficients used are those from the most
recent drift scan (drift_scan == "pm") taken prior to the date in

If verbose=yes, the calculated offset angles are printed to STDOUT
as the task executes.


1. Determine the camera offset angles for a set of Teide calibrated
velocity images.

pi> camoffset tdvci*.imh

2. Deterine the camera offset angles for a set of Teide calibrated
velocity images using only the drift scan results.

pi> camoffset tdvci*.imh drift_scan+


Nothing significant.



imoffset, xoffset

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