User's Guide to IRCAL

Table of Contents

Summary Table
Quick start
Instrument Characteristics
Software Overview
Data File Info
Filters, Grisms, Polarimeter
Nodding and Dithering Scripts
Observing Procedures and Tips
Technical Details
TechRef: (Dis)Assembly

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Lick Strehl Tool

The Lick Strehl Tool is an IDL program to measure the Strehl of a 3-m AO IRCAL image. The program is based on the Keck Strehl measuring tool written by Marcos van Dam and customized for Lick AO data by Elinor Gates.

The program is started by typing lickstrehl at the IDL prompt. It will bring up the GUI shown below.

To use the tool, simply input a data image file name or click on Browse to select a file (the default directory is the current IRCAL data directory). Then choose the filter that corresponds to the data file.

Estimating the background and using Autofind to locate the brightest object in the image are optional. If you don't use Autofind you will have to click on the object after pressing the Go! button to indicate which object you wish to measure.

By default the photometry radius is set to 2.0 arcseconds, but you may change this to accomodate the conditions under which the data was taken.

The calculated Strehl and FWHM are displayed in the bottom panel of the GUI.

The selected image, with photometry and sky (if estimate background is on) radii, is displayed in the upper image window. The perfect PSF is displayed to the lower left, and the measured PSF is displayed to the lower right.

To exit the GUI, click the Dismiss button.

Elinor Gates
Last modified: Thu Mar 1 10:06:12 PST 2007