UH Hilo Educational Telescope
The telescope to be installed within the upgraded dome, beginning Late 2008, is presently being built by Equinox Interscience. Below are some photos and descriptions of the work in progress.
Equinox Interscience President, Russ Mellon, with the UHH telescope polar axle (south end up in this picture). The right ascension
drive gear and the tube fork assembly bolt to the flanges on the bottom
(north end).
The North polar axis bearing with an assist by UH
Hilo Professor Bill Heacox. The weight of the bearing is 320 pounds.
The thick blank (a 6:1 aspect) enables the mirror
to hold its figure under varying gravitational loads and will be supported
in the telescope by a modified whiffletree, using large triangles
that each support smaller triangles as the telescope moves about the
sky. This type of mirror cell support structure holds the mirror so
gravity won't distort its surface.
The 0.9-meter mirror blank, prior to figuring and polishing. The substrate material is Zerodur, an ultra-low-expansion glass/ceramic compound that allows the mirror to operate over a large range in temperature without loosing its figure to thermal expansion. The finished mirror will weigh about 500 pounds.
The figuring/polishing lap is used to shape the
0.9-m mirror. The material of the lap is granite and is grooved for
circulation of the grinding compound. The lap will be placed on the
mirror blank and moved across it to produce the desired shape.
A technician adds water to the grinding meduim on the 36" mirror
surface in a recent (December 2006) photo. The grinding medium,
here, is 9 micron grit. The lens figuring was completed
about Christmas, 2007.
The mirror figure testing optical bench. A small
lens (at left) is used to distort the beam from a perfectly figured
mirror into that of a spherical mirror, which is tested for aberrations
by a knife-edge. This is the same procedure that was used to produce
the original, troubled, Hubble Space Telescope mirror. They got it
wrong by incorrectly placing the lens. The UH Hilo mirror will be
redundantly checked to ensure that the problem does not happen to
this one.
Telescope fork truss weldment. The load bearing structures are the truss tubes. These will soon be covered with steel skins welded to the surfaces and finished.
Polar axis assembly, with the telescope main drive gears, mounted on base, front view.
Final assembled dome at factory, ready to disassemble, crate, and ship to Hawaii. The dome was reassembled and installed at the summit of Mauna Kea.
Final assembled dome installed on the recently upgraded observatory building at the summit of Mauna Kea. We are currently awaiting Equinox to complete testing of the telescope and then to the ship it from Colorado. Installation of the telescope into the observatory has been delayed until mid-2009.