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WIYN Moves Toward Operation in 1994 (1Sep93)
(from KPNO, NOAO Newsletter No. 35, 1 September 1993)

The WIYN Project is on schedule for early scientific operations and
shared-risk observing in late 1994; much progress has been made since
the report in the June Newsletter. The alt-azimuth telescope mount was
shipped to Kitt Peak in mid-May. Teams from  the WIYN Project,
NOAO/KPNO, and the manufacturer, L&F Industries, were involved in the
on-site assembly. Installation of the major structure took place in the
week of 17-22 May. The telescope drives, limit switches, brakes, and
encoders were also installed during that period. Dummy weights for the
primary and secondary mirror assemblies were used to balance the Optics
Support Structure in elevation, and the azimuth, elevation, and
instrument rotator axes were tested.

The current effort at the Observatory centers around cabling and
preparing for installation of the controls.  The University of
Wisconsin delivered the telescope servo amplifiers and power supplies
in June and tested them under manual control. At that time ethernet
cabling was installed throughout the building. Installation of the
telescope control computers is scheduled for August, after which time
closed loop testing of the drives will begin.

The NOAO Primary Mirror Group continues fabrication and assembly of the
mirror cell and supports. The mirror supports are being assembled as
parts arrive from suppliers. Work on the electronics and controls for
the active supports is well underway and on schedule. Plans for
integrating the mirror assembly with the WIYN telescope are being
coordinated with the WIYN Project staff. Work on the thermal control
has centered primarily on the assembly of the chiller that supplies
conditioned water to the heat exchangers in the cell.

Contraves is polishing the 1.2-m secondary mirror for WIYN. By mid-June
a 5 wave peak-valley surface finish was achieved using profilometry to
guide the figuring. A metrology mount and test optics have been
fabricated, and interferometric testing is expected to start in July.
In the meantime, fabrication of the secondary mirror cell is well
underway at NOAO and is expected to be complete prior to delivery of
the mirror.

Work on the 1.1-m tertiary mirror at Kodak is nearing completion
pending results of the final tests.  The mirror was initially polished
to 1 wave peak-to-valley on Kodak's large planetary polisher and then
placed in their ion polisher for two finish runs. Delivery is expected
in July or August.

The tertiary mirror cell design is complete and ready for fabrication
following completion of the secondary mirror cell. Both the secondary
and tertiary mirrors will be supported using a common pressure/vacuum
system. For the secondary, the space behind the mirror will be
partially evacuated to support its weight. An air bag will be provided
for the tertiary.  The pressure/vacuum system has been prototyped and
is under test at NOAO.

The tertiary mirror assembly is supported by the primary mirror cell
through the central hole in the primary mirror.  A rotator and tilt
mechanism allows the telescope beam to be directed to any one of three
instrument ports. This mechanism and associated structure is being
fabricated by L&F Industries with delivery expected in August.

The design of the 1 degree wide-field corrector for use with the
Multi-Object Spectrometer (MOS) has been finalized, and fabrication is
scheduled to start in August. The MOS will be semi-permanently mounted
on one of the two Nasmyth instrument rotators.

The other Nasmyth focus will be available for various other instruments
including a CCD imager.  Science instruments at that focus will mount
on an adapter box (IAS) that will provide target acquisition, guiding,
atmospheric dispersion compensation, wavefront sensing for active
optics, and spectral calibration sources. A critical design review on
the IAS was held 28 June.

Under the current schedule, telescope commissioning will start early in
CY 1994. Planning for the commissioning and operations phases is
underway.

Matt Johns, Caty Pilachowski

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