DEIMOS user script ampang

Name

ampang -- compute distance + bearing between two locations on DEIMOS image

Purpose

Given two (x,y) pixel locations measured on a DEIMOS image,
compute the angular separation of the points and the angle
between them.

Usage

ampang x1 y1 x2 y2

Arguments

x1 = column of first position
y1 = row of first position
x2 = column of second position
y2 = row of second position

Output

The angular separation and angle (measured in various
coordinate systems) are written to stdout.

Restrictions

Exit values

0 = normal completion
1 = wrong number of arguments

Example

1) Compute the offset and direction between an object at pixel
(100,100) and another at (200,200):

> ampang 100 100 200 200
Normal coordinate system (0 deg to right, 90 deg up):
Amplitude = 30.2642 arcsec
Angle = 45 deg

Astronomical coordinate system (0 deg up, 90 deg to left):
Amplitude = 30.2642 arcsec
Angle = 315 deg