User's Guide to the Crossley Telescope

Table of Contents

Ground Level
Dome and Platform
Head Rotation
Dec Tangent Arm
Position Indicators
Mirror Cover
Dome Slit
Access Ports
RA Drive Preload
Operating Limits
New Telescope Drive

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The Crossley 36" Reflector, originally constructed by Andrew A. Common in 1879, was moved to Lick Observatory in 1896. Improvements to the telescope (to the extent that no original telescope parts remain), occurred during the late 1800's through about 1910 to bring the telescope to its current configuration. The f/5.8 primary mirror yields a plate scale at the prime focus of 38.6 arcseconds per millimeter.

The Crossley is not a computer controlled telescope and has only tracking motors, thus the telescope must be slewed by hand. This poses unique hazards in the dome and when working around the telescope.

Lick Observatory does not provide any facility instruments for use at the Crossley Telescope. A prime focus spider is available for observers to mount their own instruments. Mounting an observer provided guide/acquisition camera is also possible. Contact a support astronomer for information on mounting instruments at the Crossley before applying for telescope time to make sure that the hardware is compatible or that proper mounting hardware can be constructed.

Information in this manual is taken nearly verbatim from The Crossley Telescope, Lick Observatory Technical Reference 5, by Rem Stone. Thus some information may be out of date, though the bulk of the material is current.

The Crossley Telescope is available to the University of California astronomical community by subscription.
Follow these links to:

Call for Small Telescope Proposals
Small telescope observing time application forms

The Crossley is a user-operated telescope. All new users must be checked out by a resident astronomer on their first night. Please request support on your time application.

Please direct questions to a Mount Hamilton support astronomer,

Crossley Telescope