FanCam
Near Infrared Linear Polarimetry

A Sample Observation
HD 109055 (unpolarized standard star)
23 Mar 2006

The illustrations below show IRAF aperture photometry from a pair of sample exposures in J with each polarizer. (These images were taken with the telescope tube on the E side of the pier.)

Note: Polarization states of the two components of the double images as shown below are fixed in pixel coordinates since the analyzers are part of the camera. When the 31-in telescope at Fan Mountain is moved from E to W of the pier on its German equatorial mount, the image itself is simply inverted, but the analysis of polarization data is unaffected in pixel coordinates.

P1 (0° & 90°)

IRAF txdump output from above image with P1 for Stokes q.
Line 1 is for 0° and Line 2 is for 90°: 

  xc        yc      sum      flux     mag    merr   image

250.811  710.338  404793.7  400919.6  9.245  0.001  bfc294
320.581  710.799  412910.   408916.  9.223  0.001  bfc294

P2 (45° & 135°)

IRAF txdump output from above image with P2 for Stokes u.
Line 1 is for 135° and Line 2 is for 45°: 

  xc        yc      sum      flux     mag    merr   image

226.288  714.258  351333.  346079.4  9.405  0.001  bfc269
273.694  668.050  353904.3  348663.9  9.397  0.001  bfc269

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Last modified: April 13, 2006

David McDavid