Subject: Hartmann testing of the 3.5m

From: Alan Diercks

Submitted: Fri, 27 Oct 95 11:21:40 -0700

Message number: 22 (previous: 21, next: 23 up: Index)

A report on recent Hartmann testing of the 3.5m is now available at:

anonymous ftp: ftp.astro.washington.edu 
          in     users/diercks/hartmann/hartmann_10_9_95.ps

and on "the web" :  http://www.astro.washington.edu/stubbs/aporeports.html

Abstract:

A classical Hartmann test was performed on the entire optical train of
the 3.5m during engineering time on October 9, 1995.  Results indicate
that the optics {\bf alone} produce images with a FWHM of .59
arcseconds and that 80\% of the encircled energy falls within .81
arcseconds.  The specification for telescope contribution to image
FWHM for the 3.5m is .24''(MILT proposal). The actual image size on a
detector is substantially larger than .59'' due the additional
degradation caused by telescope dynamics, atmospheric and enclosure
seeing, and residual collimation error which add in quadrature with
the optical contribution.  These results are in surprisingly close
agreement with predictions based on profilometry of the secondary
mirror, lending credence to the supposition that the secondary is the
dominant source of the observed optical degradation.  Alleviating this
problem should reduce the achieved FWHM in median seeing by about
0.2'', and would allow us to take full advantage of superb conditions
when they arise.

-- 
Alan Diercks				Mail address while in Washington:

Office: (206) 543-9373			University of Washington
Lab:	(206) 616-2960			Dept. of Astronomy
Fax:	(206) 685-0403			Box 351580
					Seattle, WA 98195-1580


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