Operator Instructions Source code

Purpose: Driftred analyzes the processed drift images generated by driftsum to determine the true east-west line as a function of hour-angle.

The input to driftred are the images generated by driftsum.

The code uses standard edge detection methods to find the path of the solar limb as it drifted across the CCD during acquistion of each "drift set". The direction should nominally be 45 degrees. Any departures from 45 degrees are a measure of the error introduced by the various miss-alignments discussed in the driftsum documentation.

Driftred applies the refraction correction and the correction for North-South motion of the solar image to each processed drift image. It produces an ASCII output file which contains a history of the processing parameters and a table of the various quantities computed by driftred as well as the final "drift" solution. Driftred names the table via: 2-character site abbreviation + dft + 2-digit year + 2-digit month + 2-digit day. eg: tddft040704.

A sample table can be seen here:

Sample history file generated by driftred

Notice that the final column is labeled "Ticks". A "Tick" is the smallest angle that the camera rotator can move. There are 6553.6 Ticks per degree of camera rotator rotation.

Driftred generates an output plot: Sample plot and updates the drift data table.

Last updated by Cliff Toner on Friday, August 14, 2005, 11:40