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Latest GBT Azimuth Restrictions

On Feb 7, 2003 a new set of GBT azimuth motion restrictions was established. These changes are a result of the completion of inspection of all wear plates and experience gained with the existing cracks.
Restrictions
(A) Slewing and sidereal tracking is allowed throughout the full azimuth range of travel. However On/off positioning, nutating, "dithering" or sudden changes in motion is allowed ONLY in the following azimuth ranges:
21 - 61
111 - 151
201 - 241
291 - 331
(B) No azimuth motion will be allowed when the temperature drops to below one degree Fahrenheit.
 
Duration of Restrictions
These restrictions will remain in effect until the major crack problems are repaired.

Three of the four wear plates with major problems will be replaced as soon as the replacement plates have arrived (~ fourth week in Feb) and their preparation work is complete. It is anticipated that these plates will be installed anywhere during the Feb 24 through Mar 13 period (if everything goes well - otherwise this may get delayed). If you have observing during this period you may loose some time (or possibly all your time depending on the circumstances).
02/10/03