Date: Tue, 20 Jan 2004 13:33:50 -0700
From: Dan Long
Subject: Re: 2.5m obslog 20040119 (MJD 53024)
>                        APACHE POINT OBSERVATORY SDSS 2.5M
>
>                                  OBSERVING LOG
>                             Monday January 19, 2004
>
>                                   (MJD 53024)
>
>.
>.
>.
>
>
>03:21Z cart 5, plt 1641 ...
>
>
>        ....gflat hasn't been taken on go to field.....
>
>----------------------------------------------
>gGuide question: we've got the following error message when we started guiding
>on the second plate this night:
>
>SOPGUI: startGuider 10
>Using 10 second gcam exposures
>2004-01-20 03:25:08Z: Using da centroider because flat does not exist
>2004-01-20 03:25:08Z: Using da centroider because flattener does not exist
>2004-01-20 03:25:08Z: Using da centroider because maskdark does not exist
>2004-01-20 03:25:08Z: Using da centroider because dark does not exist
>2004-01-20 03:25:08Z: Using da centroider because mask does not exist
>2004-01-20 03:25:08Z: Using da centroider because fiberData does not exist
>Sky values: 138 138
>
    If you tried gGuiding without yet having a guider flat, you'd see
errors like this, since it is the guider flat which allows the
creation of the items above.
    The old guider shouldn't have worked very well either as the
position of the fiber block for this set of observations would not
have been measured.  I think the only reason the old guider doesn't
complain the same way is because it (unwisely?) uses some default
value (the starting set of circles you see on the guider flat).
    So if the above errors indeed happened while guiding with out a
flat, I would recommend continuing to use the new guider.
				Cheers,
				  Dan