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TIC_ONE

TIC_ONE

Name


TIC_ONE

Purpose


Determine the position of the first tic mark for astronomical images.

Explanation


For use in labelling images with right ascension
and declination axes. This routine determines the
position in pixels of the first tic.

Calling Sequence


tic_one, zmin, pixx, incr, min2, tic1, [RA = ]

Inputs


zmin - astronomical coordinate value at axis zero point (degrees
or hours)
pixx - distance in pixels between tic marks (usually obtained from TICS)
incr - increment in minutes for labels (usually an even number obtained
from the procedure TICS)

Outputs


min2 - astronomical coordinate value at first tic mark
tic1 - position in pixels of first tic mark

Example


Suppose a declination axis has a value of 30.2345 degrees at its
zero point. A tic mark is desired every 10 arc minutes, which
corresponds to 12.74 pixels. Then
IDL> TIC_ONE, 30.2345, 1, 12.74, min2, tic1
yields values of min2 = 30.333 and tic1 = 5.74, i.e. the first tic
mark should be labeled 30 deg 20 minutes and be placed at pixel value
5.74

Revision History


by B. Pfarr, 4/15/87
Converted to IDL V5.0 W. Landsman September 1997



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