Wise Observatory: Its 1971 Opening and Early International Observations

The observatory's full name commemorates Florence and George Wise. Tel Aviv University built it as a field research facility for its physics and astronomy department, with assistance from the Smithsonian Institution. Myron Lecar coordinated cooperation with American astronomers, connecting the new observatory to overseas research networks during planning.

First director Uri Feldman later recalled that Yuval Ne'eman invited him to lead construction in late 1969. Lecar and John Bahcall also served on the planning committee. Feldman's responsibilities encompassed site selection, buildings and equipment installation: donor support for a telescope had to become a station capable of sustained observation.

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Feldman began site selection in early 1970. He needed distance from city lights, while keeping roads, electricity and water within the project's means. He chose a hill on the Negev plateau about five kilometres outside Mitzpe Ramon, near the northern edge of the Ramon crater. He and astronomer Nissim Vidal checked nighttime image quality with a small telescope and discussed shielding outdoor lights with the town authorities.

Zalman Enav designed the building. Construction included connecting roads and utility lines. A ten-metre dome topped the two-storey concrete structure. The plateau offered many clear nights, while coordination of the dome, telescope, controls and staff supported sustained observations.

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The principal instrument was a Boller and Chivens reflector with a 40-inch aperture, approximately 102 centimetres, using a wide-field Ritchey–Chrétien design. Early instruments included an image-tube spectrograph and a photoelectric photometer. An electronic system centred on a Hewlett-Packard 2114B computer controlled pointing, corrected tracking rates, recorded meteorological data and handled instrument output.

A photograph caption in the February 1972 report states that the telescope was working in June 1971. The inauguration took place on 26 October, attended by Fred Whipple, director of the Smithsonian Astrophysical Observatory, and others. Several months separated equipment operation from the public ceremony, and scientific observations had already begun.

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During Apollo 15, Wise joined coordinated ground and spacecraft observations. American Science and Engineering's mission report records visible-light measurements of Scorpius X-1 at four-minute resolution. The Crimean Astrophysical Observatory also provided optical data, while Westerbork in the Netherlands contributed radio observations.

The campaign compared brightness variations of the same object across wavelengths. During the relevant spacecraft observations, North America was in daylight while ground stations farther east could observe visible light at night. Wise's longitude supplied data unavailable then to American ground observers, allowing variations in different bands to be compared in a common time frame.

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Between 6 July and 19 August 1972, John and Neta Bahcall photographed HZ Herculis with the Wise 40-inch telescope and obtained 81 blue-magnitude measurements. Nearby standard stars calibrated brightness, and observations from different nights were arranged by phase to construct a light curve. Each plate had a fifteen-minute exposure, with measurement errors varying with brightness. Photoelectric standards in the nearby globular cluster M13 provided the main calibration, and the light curve was organized using the X-ray eclipse period.

The measured period of about 1.700 days agreed with Hercules X-1's known X-ray eclipse period, and the phases also matched, establishing HZ Herculis as its optical counterpart. The paper appeared that November. Linking ground-based photographic photometry to a satellite discovery, the result demonstrated the new observatory's early practice: accumulate repeated observations of a specific object, then compare them with measurements from other instruments and institutions.

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