What's where at Lick Observatory on Mt. Hamilton

Notes on the determination of Mt. Hamilton Positions

Original Site Plan for Lick Observatory

Holden published this in PLO I, 34a (1887). Eccentricities between the major instruments are given in the text, but others are only available from this map.

USGS 7.5 minute Lick Observatory topographic quadrangle

Experience shows that the positions of objects on the black printing layer can be trusted to 5 meters or better in regions where they are not crowded by other objects or a road.

Wilsey, Ham, and Blair Engineering Survey, 1961

This firm performed a detailed ground and aerial survey of the mountaintop and the layout of the North Spring. The ground traverse points are marked on the resulting prints. The State Plane Coordinates (SPC) from this survey are the best source for accurate positions of most of the structures on Mt. Hamilton. Klemola made detailed measurements of these.

Wildman and Morris Engineering Survey, 1977

These maps are available as blueprints constructed from aerial survey photography. Their intent is to show the layout of the underground utilities on Mt. Hamilton. They are overlayed with contours from photogrammetry and with tickmarks denoting State Plane Coordinates (SPC) for the California Coordinate System, Zone 3, measured in survey feet and based on the 1927 NAD. There is significant parallax in these photographs. Nearby domes at different elevations in the overlap region of two maps show position shifts of 5 meters depending on their elevation. It is also not known whether the SPC are simply based on the dome positions from USGS topos.

University of California Building Code Map for Mt. Hamilton

The UC assigns a 4-digit code number to each building. All buildings associated with the Santa Cruz campus start with the digit 7. In 1970 A. Bumgarner drew a map of Mt. Hamilton which identifies each structure. This was revised in 1973 by Greeby. The map appears to have been based on the 1961 engineering survey.

Small Dome

The position comes directly from the NGS data sheet for PID = HS4865. Recall that the top of the small dome was the first reference point established on Mt. Hamilton by the USC&GS in 1883. The horizontal eccentricity between the small dome and the nearby benchmark was measured at the time the benchmark was set.

Small Dome Eccentricity

The position comes directly from the NGS data sheet for PID = HS4863. This site was directly occupied by a GPS receiver in the charge of Santa Clara County on 1992 May 22 as part of a California High Precision Geodetic Network (HPGN) densification survey.

Brick and Cement Water Tank on Kepler Peak

The position comes from measurement of the 1977 engineering survey map and from the USGS 7.5' Lick Observatory topographic quadrangle. Historically it is important to note that Kepler Peak has housed at least 3 other water tanks previous to the ones extant in 1996. Two of these were wooden, but another was brick.

There are still traces of a large rectangular brick and cement tank which once occupied the center of the peak. The foundation of the 150000 gallon tank is also brick, which may indicate a previous tank.

Heliostat

The position is derived using the offsets and charts from Holden applied to the position of the small dome.

Photographic Laboratory

The position is derived using the offsets and charts from Holden applied to the position of the small dome.

Large Dome for the Lick 36 inch refractor

The position comes directly from the NGS data sheet for PID = HS4868.

Transit House

The geodetic position is derived using the offsets and charts from Holden applied to the position of the small dome.

Meridian Circle House

The geodetic position is derived using the offsets and charts from Holden applied to the position of the small dome.

Meridian Circle South Mire

The geodetic position is derived using the offsets and charts from Holden and from Tucker applied to the position of the small dome.

Meridian Circle North Mire

The geodetic position is derived from land imagery as seen in online Google maps and Microsoft maps based on an interpretation of the position given in Lick Observatory Bulletin # 436 (1930)

6.5 inch Clark Refractor Dome

The position is quite rough and is based on the best guess of the position as seen in the early photographs.

USC&GS West (Longitude) Transit Site

The geodetic longitude is derived using the offset from the Transit House. The latitude is the same as for the East site. [USC&GS Special Pub. 110, 145 (1925)]

USC&GS East (Latitude) Transit Site

The geodetic position is derived using the offset from the Transit House published in 1899. The longitude is 2.019 m east of the West site. [USC&GS Bull. 13 (1899)]

The Crossley Dome

The position comes from measurement of the 1961 engineering survey map and from the USGS 7.5' Lick Observatory topographic quadrangle.

Old Crocker Dome

The position comes from measurement of the 1977 engineering survey map.

Bamberg Transit Pier

The position in longitude comes from the published distance between the Meridian Circle and the Bamberg transit. [BIH, 2aOIL 7, 673 (1941)] The position in latitude comes from a photograph taken in 1934 which shows a hutch that is located at the correct longitude. It is between the Meridian Circle and the bridge to the Old Dorm, near the north edge of the plateau. [PASP 47, 89 (1935)]

Astrograph Dome

The position comes from measurement of the 1977 engineering survey map and from the USGS 7.5' Lick Observatory topographic quadrangle.

Shane Dome

The position comes directly from the NGS data sheet for PID = HS4867.

Coude Auxiliary Telescope coelostat

Starting from the position of the Shane Dome, a rough estimate of the distance to the CAT was determined from the 1977 engineering survey. A better position could be obtained using Shane and CAT blueprints.

New Crocker Dome

The position comes from measurement of the 1977 engineering survey map.

wooden pad and pier on Tycho Brahe Peak

The position comes from measurement of the 1977 engineering survey map.

Tauchmann Dome

The position comes from measurement of the 1977 engineering survey maps and from the USGS 7.5' Lick Observatory topographic quadrangle.

24-inch/KAIT Dome

The position comes from measurement of the 1977 engineering survey map. It occupies part of the land once covered by the rectangular brick and cement tank.

150000 gallon water tank on Kepler Peak

The position comes from measurement of the 1977 engineering survey map and from the USGS 7.5' Lick Observatory topographic quadrangle. Its foundation is made from brick which may or may not date from a previous structure at the same site.

261000 gallon water tank on Kepler Peak

The position comes from measurement of the 1977 engineering survey map. It may partly overlie the site of the rectangular brick and cement tank.

CCD Comet Camera Outhouse

Starting from the position of the Shane Dome, a rough estimate of the distance to the outhouse was determined from the 1977 engineering survey.

The Rev. Laurentine Hamilton Monument Cuppola

The position is not yet determined. The location needs to be paced off.