Running wbFitSingle
wbFitSingle accepts the output file from wbCalib, and translates the data into an angular diameter. The wbCalib file must, however, only have one target star in it. If you have more than one target star (i.e., a check star), you will need to separate out the star for which you want an angular diameter. You can do this using the "grep" command (see below). Once you have a *.wbOut file with one target, move to the directory in which that file is located. Then execute:

~/develop/wbFitSingle/wbFitSingle HDC12345.wbOut

The output will appear in the following format:
(# of points averaged)/(total # of points); Output diameter +/- error (mas); weighted wavelength; Average residual; X^2/DOF; file where predicted V2 was written.

  1. of points averaged- FitSingle will examine the Visibility points and throw out any outlying points that are more than 3 sigma away from the fit curve. For this reason, the number of points averaged to obtain an angular diameter may be less than the total number of points.

Output diameter error- this number takes into account the uncertainty in the visibilities.

Weighted wavelength- Sometimes certain spectral channels will get significantly more photons than others. The detection system at PTI therefore counts the number of photons in each channel, and then weights the wavelengths accordingly. This results in a different "white light" wavelength value for each data point. These weighted wavelengths are then averaged over all the visibility points to give an average weighted wavelength, which is the actual output of FitSingle.

Average Residual- this number is the average difference between the fit and the measured visibility values. It theoretically varies between 0 and 1, but should be no more than 0.1.

X^2 is the goodness of fit value. (see Bevington & Robinson "Data Reduction and Error Analysis for the Physical Sciences") 2nd Ed. p.71

Using the grep Command
The grep command allows you to pick out only the lines in a file that contain a certain string of letters/numbers. Say that I want to pick out only the HDC12345 target out of etaBoo_070619a.wbOut, which contains that target and another. I would execute the following:

grep HDC12345 etaBoo_070619a.wbOut > HD12345.wbOut

After the grep command, specify the string to search for, followed by the file to look in, and then the file that I want the output to go into. Now, all the lines containing that string will be spit out into HD12345.wbOut.