scan file, repeat=?, scale=?
Perform a scan relative to the current telescope position.
ScanFile file
Count repeat
ScanScale scale
myscan.scn
, repeating the body of this scan
ten times, with half the amplitude described in the file.
scan myscan.scn, repeat=10, scale=0.5
# Duration Azimuth Elevation Deck Angle # (s) p v a p v a p v a START: 0 0.0 -4.0 0 0 0 0 0 0 5 -20 0.0 4.0 0 0 0 0 0 0 5 0 0.0 -4.0 0 0 0 0 0 0
The first two lines are examples of arbitrary comments, and the third an arbitrary blank line. Comments can be written at the end of any line, provided that they are preceded by a # character.
The line that is started with the word START:
, must
always be the first line in the file that is neither a
comment-line nor a blank line. The six numbers that follow it
indicate the azimuth, elevation and deck-angle positions,
velocities and accelerations at which the repeating body of the
scan should start. These numbers have units of degrees, degrees/s
and degrees/s^2, respectively. The positions are relative to the
axis positions that the telescope had before the scan was
started, whereas the velocities and accelerations are absolute.
The two lines that follow the starting line, each start with a number which specifies the duration of a move in integer seconds. During this time, the azimuth, elevation and deck axes are are to be moved smoothly to the positions, velocities and accelerations indicated by the remaining 6 numbers on the line. Note that the positions, velocities and accelerations of the final line, must match those of the starting line, such that the scan can be seamlessly repeated.
The trajectory followed is the cubic interpolation between the
positions, velocities and accelerations of successive lines.
If the above file is given the name myscan.png
, and is
executed as follows, using the scan
command:
scan myscan.scn, repeat=3Then the result is the following trajectory in azimuth, in which the body of the scan is repeated 3 times. Since the positions, velocities and accelerations specified above for the elevation and deck axes are zero, these axes don't move.