Toward First Light on the Magnum Mirror Telescope

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Session 41 -- The Status of Large Telescope Projects, Instrumentation and Plans for Large Science Programs in the Areas of Wide-Field Surveys
Oral presentation, 8:30am - 12:30pm, June 14, 1995, 9:20am - 6:30pm

[41.06] Toward First Light on the Magnum Mirror Telescope

Frederic H. Chaffee and Dan Fabricant (MMT Observatory and Smithsonian Astrophysical Observatory)

Initiated in 1986, the project to convert the MMT from a six-mirror, 4.5-m equivalent telescope to a single mirror 6.5-m one was undertaken in order to more than double its light-gathering power and to increase its field of view from the current 4 arcminutes to one full degree. This project is now entering its final stages.

The f/1.25 6.5-m honeycomb borosilicate mirror blank, created using the spin-casting technology developed by Roger Angel and his colleagues, was cast in 1992. The cell, optics support structure (OSS), and aluminizing head were designed by Simpson, Gumpertz \& Heger and fabricated by TIW Fabrication and Machining Inc. of Albuquerque. Modifications to the existing MMT building, whereby the doors will be bulged to provide increased swing space and rear doors added to improve air-flow, are due to be completed in August 1995.

Primary mirror polishing is scheduled to begin in early summer 1995 and to be completed in early 1996. There will follow a period of laboratory testing of the mirror and its support system in its telescope cell, after which the existing telescope will be decommissioned for installation of the cell, OSS and mirror into the existing yoke.

Three Cassegrain focal ratios will be provided: f/9 to feed existing MMT instrumentation, f/15 for IR/adaptive optics applications, and f/5.4 for wide field use. First light for f/9 is anticipated for early 1997, followed by f/5.4 and f/15.

The first new instrument designed specifically for the 6.5-m will be the Hectospec, a 300 fiber spectrograph for use at the f/5.4 wide field focus.

This presentation will describe the present state of the telescope and of the Hectospec.

8:30a program listing