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Laser Traffic Control System (LTCS)

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How to start:

http://ltcs/screens/main.php

Documentation:

Laser Traffic Control System User Manual - Version 1.0

Purpose:

Predict collisions between the laser launched from the WHT and other telescopes up to 3 hours in advance and control Beam Dump avoiding collisions when the WHT does not have priority. To give priority on a first come first served basis.

Policy:

The telescope first on target has priority.

Possible situations:

The LTCS will allow the Beam Dump to move ‘OUT’ when:
 
· A collision is predicted and the WHT has priority.
· A collision has occurred but the WHT has priority.
· A collision is predicted and the WHT does NOT have priority, until the collision occurs.
 
 
The LTCS will maintain the Beam Dump ‘IN’ when:
 
· A collision has occurred and the WHT does not have priority. 

Problem solving:

LTCS server:
When stale information is presented for the WHT and/or the INT the LTCS servers need to be restarted.
You connect to the server from the LTCS main page. Passwords have been communicated to the TOs.
There are no circumstances under which you would need to change of override the FOV (1 degree) in either of the servers.
Other default parameters are for the WHT: Period=1sec and Pointing Noise=0.0001
 
LTCS Allow Obs Flag error:
On the GLAS Beam Dump GUI there is an item called "LTCS Allow Obs Flag". If this is in error it means that the LTCS has lost control (communication) with the beam dump and won't be able to deploy the BD if needed.
It is possible to manually control the Beam Dump, however before the TO will have to consult with the observer. If there is any doubt, new observations should not be started until the problem has been resolved.
In this case TOs are responsible for deploying the BD just before the collision is due to start.
 

Known Issues:

• When observing a target in the infrared, the standard observing procedure is to dither the telescope. Unfortunately a small dither is sufficient for the LTCS to regard the WHT as having moved to a new position, thus (i) recomputing all the LTCS collisions and (ii) resetting the timestamp at which the WHT arrived at the target. The result of this is that WHT observations with INGRID can be terminated at any moment due to a collision with another telescope, even if the WHT has been pointing at its field for several hours while the other telescope has just moved in collision with it.

• Tracking NEOs (near earth objects) or e.g. planets we expect problems as then we don't track purely siderial. We have seen that the LTCS struggles in this case in the past. Tracking such objects your experience with the LTCS is important input to us, therefore please report problems.

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This file: http://www.ing.iac.es/~ops/private/wht/LTCS.html
Jürg Rey, 16 June, 2008