Tools for Automated Observing
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  System requirements
Getting Started
  Modeling slew times
  Measuring camera
  download times
  Specifying filter
  names and numbers
  Modeling the local
  Creating user profiles
  Initializing target
  Customizing the
Daily Operation
  Starting observatory
  control software
  Updating target
  Generating a list of
  potential targets
  Preparing a list of
  observation requests
  Running the
  Starting scheduled
Image Acquisition with
the MU Script
  Customizing the
  Starting MU
  Sequence of events
  during an observing
  run using MU
Timing Refinement
  Collecting timing
  Analyzing timing
  Adjusting the
  empirical timing
Other Tools
  Slew time
  measurement script
  Minor Planet Checker
  query script
  Regression program
  Software updates
  License agreement
  Contact the author
Timing refinement

Analyzing timing data

The text file containing timing error data should be plotted with some graphics program. In the simplest situations, the timing errors will be well approximated by a linear function of exposure number. The slope of this linear function (which may be determined using program regress or any other linear regression program) is equal to the average accumulated timing error per exposure.

In some cases, the timing error plot will show more complex behavior, which cannot be well approximated by a linear function. This is often caused by inaccuracies in the slew time models, equipment parameter values, or the duration of focus breaks assumed in the scheduler configuration file. For example, if the assumed duration of focus breaks is significantly different from the actual average duration of a focus break, the timing error plot may exhibit sharp discontinuities (jumps) at the exposure numbers which are adjacent to focus breaks. In such situations, improving the models and parameter values in the scheduler configuration file may lead to timing error plots which may be modeled by a linear function.

Adjusting the empirical timing correction

Once the average accumulated timing error per exposure has been computed, it may be added to the current value of the
empirical timing correction in the scheduler configuration file, producing the new value of the timing correction. For example, if the last observing run was scheduled assuming a timing correction of +2.5 sec on the scheduler configuration file, and the average timing error per exposure for that observing run was -4.1 sec, the new timing correction in the scheduler configuration file should be +2.5 + (-4.1) = -1.6 sec.

Note that adjustments of the timing correction may be done after any observing run (not just the first), in an attempt to reduce the timing errors. In particular, it is useful to analyze the timing errors after any changes in equipment configuration, in the parameters in the scheduler configuration file, or in the focus parameters in the MU script configuration file.

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© 1999-2004 Paulo Holvorcem