Guider Issues

A yellow warning box appears

On rare occasion, the apfguide_gui window is replaced by a yellow warning box. It says in clear language that restarting the GUI is not required, and it is right. The text of the message indicates the true nature of the problem; a restart of a KTL dispatcher is usually required. The error message indicates which service needs to be restarted; it is either apfguide or eosgcam. To address this problem:

ssh dresden
apf restart apfguide            # if apfguide needs restarting
apf restart eosgcam             # if eosgcam needs restarting


Prior to August 2013, there was a bug in the KTL Python module that provoked this ‘yellow box’ warning if a KTL service service locked up twice while the KTL Python client application persisted. This specific bug is now covered in the KTL Python unit tests, and should no longer trigger spurious ‘yellow box’ warnings.

The value of the semi-major axis is large

If the value of a is much larger than the value of b, check to see what the value of theta is. If that number is 90 or -90, then the value of a is likely the result of the star being, very bright. This can happen because the camera does not have a shutter, so when reading out, the array is still being illuminated. This causes a long streak which the guider software assumes is part of the star.

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