Rutgers Instrumentation Effort for SALT

The University of Wisconsin, Rutgers University,  and the South African Astronomical Observatory  have designed and fabricated the Prime Focus  Imaging Spectrograph (PFIS), one of the First- Light Instruments and one of the principal  instruments for the SALT Telescope. The lead institution is the U. of Wisconsin (K. Nordsieck, PI) and more  details of the overall instrument can be found at  the Wisconsin PFIS home page. SAAO is providing the  image sensors for all SALT instruments. Rutgers is  providing the Fabry-Perot subsystem in PFIS and the  overall mounting structure. 
Cartoon of PFIS Instrument with man for scale

17-Mar-04. The PFIS Structure hanging up side down to weld those hard-to-reach places. The cylindrical element at the center, which will
hold the optical collomator, is more visible in this picture.
Two completed invar optical rails, stacked on top of each other, waiting to be attached to the PFIS structure.
The fabrication of the PFIS Structure as it stood Monday afternoon 8-Mar-04. All of the structural platforms and rails are positioned properly above the base. The pictures above and below are from opposite sides.

Invar welds.

5-Jan-03. The manufacturing jig spindles to establish various arcs of rotation for the optical rails are shown at the left. A special jig for cutting the unusual angles needed for the invar braces is pictured on the right. The jig rotates in the azimuthal and altitude planes. Aluminum test braces are cut and tested first.

25-Nov-03 The fabrication/shipping   jig as returned from thermal stress relieving and machining. The pads on the opposite side and the facing surface are parallel to better than 50 microns (2/1000 of an inch) over the 2 meter surface! This jig will hold the PFIS structure to tight tolerances as the entire structure undergoes thermal stress relief. It will also serve as a shipping jig. A blow up is to the right.

25-Nov-03 The "Crash Dummy" was fabricated two weeks ago. It is exactly the size and weight of the real SALT Etalons, one large and heavy optic. This dummy will be used as a test device for the insertion mechanism, including testing for adequate rigidity. It is best to use a "Crash Dummy" prior to committing an expensive optic as a fit check.
12-Nov-03 Welding area, which is dedicated to the SALT/PFIS effort. A drill press with a very deep through that will be used in conjunction with this welding area is pictured further down the page. The entire PFIS structure will be on a large jig table that can be rotated about its center. This will provide precise alignment of one portion of the structure to another as it is fabricated.
17-Oct-03 Continuation of the fabrication of the jig, which will be used as a fabrication and shipping fixture. The farground structure is ready to be shipped for thermal stress relief and final milling of the pads. These two portions of the jig will be attached forming an excellent surface for fabricating the PFIS structure.
Ernie Erskine is an expert in welding.     He plays a crucial and invaluable role in the welding of the invar frame. 
Picture taken on 25-Aug-03. Pictured is shop foreman, Val Myrnyj, beginning the fabrication of a steel and aluminum jig that will be used extensively to fabricate, stress relieve, and ship the PFIS structure made of invar. This jig will hold optical alignment to 1 mil as the PFIS structure is thermally stress relieved. It will also be used to ship the PFIS structure to Wisconsin and then on to South Africa.

Most of the crew are on the job. Can you find 5? Jig rail on crane

Eric Paduch Dedicated PFIS Welding Area in High Bay. A drill press with a very deep reach has been refurbished.

Area of machine shop set aside for PFIS drawings.
Val Myrnyj explains structural detail to Chuck Joseph

Some of the guys

Bill Schneider Arvid Knutsen Art provides some temporary extra help

Photos taken by Tim Koeth and Chuck Joseph

Email Contact 732-445-3704 Dr. Charles L. Joseph
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