Dennis Crabtree

Dominion Astrophysical Observatory

Title:  Canadian Large Optical Telescope Studies
 
Abstract: 
        As part of our Long Range Plan for Astronomy, Canada has started
studies of a Very Large Optical Telescope (VLOT).  The goal is to have the
telescope operational by early in the next decade to complement the
science discoveries of the NGST and ALMA. This design is suitable for
location on the Mauna Kea summit ridge, and could replace the current
3.6 m CFHT telescope. The telescope structure provides room for two
vertically oriented Nasmyth instruments, implements a very stiff
monocoque mirror cell, and offers a short and direct load path to the
telescope mount. A Calotte style dome structure offers many advantages
over current designs including lower and more even power requirements,
and a circular aperture that will better protect the telescope structure
from wind buffeting. The science requirements are presented, and the
telescope optical design, primary mirror pupil segmentation options,
including hexagonal segments and a radial segment design with a central
8 m mirror, are considered. Point spread function plots and encircled
energy calculations show that there is no significant diffraction
performance difference between the options except that hexagonal
segments in the 1 m point-to-point range appear to deliver poorer PSF's
as compared to 2 m and larger segments. Plans for implementation of a
Matlab based integrated telescope model are discussed.