From: Antonin Bouchez <abouchez@astro.caltech.edu>
Date: July 17, 2006 9:40:13 PM PDT
To: Antonin Bouchez <abouchez@astro.caltech.edu>
Cc: Viswa Velur <vnv@phobos.caltech.edu>, Hal Petrie <hlp@deimos.caltech.edu>, Anna Moore <amoore@astro.caltech.edu>, Mitchell Troy <mtroy@jpl.nasa.gov>, Chris Shelton <cshelton@s383.jpl.nasa.gov>, Jenny Roberts <jerobert@s383.jpl.nasa.gov>, Ed Kibblewhite <edk@oddjob.uchicago.edu>, Richard Dekany <rgd@phobos.caltech.edu>, Andrew Pickles <pick@phobos.caltech.edu>
Subject: Acquisition camera LGS platescale

All,

I measured the acquisition camera LGS platescale from the data which we took on 7/14 UT, in which we simultaneously dithered an NGS on PHARO and the LGS on the acquisition camera by commanding FSM moves.Ê The platescale I find from these data is:
			X = 0.156 +/- 0.03 arcsec/pixel
			Y = 0.169 +/- 0.01 arcsec/pixel
These average to 0.163 +/- 0.01 arcsec/pixel, which is consistent with the 0.162 arcsec/pixel which Chris derived from Zemax and the physical pixel scale of the Pulnix camera.Ê Thus, the smallest LGS which we observed this run was:
			FWHM = 15.6 pixels = 2.54 arcseconds at 04:32 7/14/06 UT.
At the time, the TMT DIMM was reporting seeing of 1.2 arcseconds.

Antonin


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Dr. Antonin Bouchez
Adaptive Optics Lead
Caltech Optical Observatories
(626) 395-8915