Use Case:
Adjust the Pointing Axis Reference Points
Description:
Correction offsets, that are due to misalignments in the Coude optics
or in other interferometer optics, are applied to the pointing axis
reference points.
For each sensor (FAS and FSS) exists:
- ATS Optical Axis (i.e. where the image is the best -may be useless for the
SW!-)
- ATS Azimuth Axis (i.e. the point around which the field moves when the Az
axis moves at Zenith)
- VLTI Pointing Axis (i.e. where we want the light to be at Lambda_obs)
- ATS Guide Star Pointing reference point (i.e. where the visible light of the Guide
Star seen by the relevant Sensor shall be placed in order to have the light
at Lambd_obs on the VLTI Pointing Axis). This last point takes into account
the atmospheric refraction and the coordinate of the selected guide Star
with respect to the observed object.
Role(s)/Actor(s):
Primary: VLTICS-ISS
Secondary: Tracking axes
Priority:Desirable
Preconditions:
Basic Course:
- Send correction offsets dU, dV, dW
Exception Course: Command failed
- ATCS converts UVW to local coordiantes and applies them to tracking axes
Exception Course: Command failed
Exception Course:Command failed
- ATCS sends back error reply
Postconditions:
- Position of the "pointing axis reference point" updated
Notes:Ref. VLT-SPE-ESO-15100-0727 1.0, p 33
The AT Coude Focus has some distortion which shall be calibrated
(e.g. using M6 to move the image of the Nasmyth Beacon all across the
Coude field)
Last modified: Mon Feb 18 14:31:11 UTC 2002
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