James A. Westphal, 74, the professed tinkerer whose innovative designs for geological instruments and astronomical cameras led him to a full professorship at the California Institute of Technology despite his lack of a graduate degree, died Sept. 8 at his home in Altadena, Calif.

The cause of death was complications of a neurological disorder possibly related to Alzheimer's disease, a Caltech spokesman told the Associated Press.

The son of "a shade-tree mechanic of the first order," Mr. Westphal displayed an uncanny ability to assemble devices out of unexpected raw materials, parlaying his creativity into a career helping other scientists overcome seemingly insoluble technical hurdles.

His knack for innovation earned him a crucial role in designing the main camera for the Hubble Space Telescope, brought him a MacArthur grant and led to a career-capping stint as director of Caltech's Palomar Observatory.

And in between those feats, he developed a small camera that was inserted into Old Faithful to determine how the geyser worked, constructed high-pressure aquariums to house fish and other organisms collected at great depths in the ocean, designed instruments to measure the properties of glaciers and, at the height of the 1973 energy crisis, devised a way to substantially lower energy use of fluorescent lights in office buildings.

Mr. Westphal's tinkering began when he was a high school student in Tulsa, where he spent his spare time building telescope mirrors. An uncle helped him get a job with a Tulsa-based oil exploration contractor so he could earn money to enroll at the University of Tulsa.

Working nights, weekends and summers, he learned how to build and maintain seismographs, gamma-ray detectors and neutron instruments for oil wells. After graduating with a bachelor's degree in physics, he joined the company full time, exploring for crude oil on Mexico's Gulf Coast and isthmus, where he camped in the jungle for six months.

He was on the team that made a major oil find under the now-famous archaeological site of La Venta.

"I always felt a sadness at having been a partner to finding oil under one of the oldest archaeological sites in the Western Hemisphere," Mr. Westphal said later.

In 1960, he began collaborating with Caltech geophysicist C. Hewitt Dix on what "he and I thought of as a nifty way to process seismic data before the days of computers that could fit on a desk," Mr. Westphal said. Dix invited him to Caltech, and Mr. Westphal spent the rest of his career there.

Typical of his work was the invention of $300 tiltmeters that he devised in 1980 to measure ground motion at Mount St. Helens that might be the precursor of an eruption.

Commercial tiltmeters cost $6,000 apiece, and scientists had to rush in and rescue them before an eruption. Mr. Westphal's instruments, insulated with plastic foam pellets and encased in half of a plastic garbage can, were so cheap they could be left in place.

While working with Dix, Mr. Westphal chatted with other Caltech researchers about interesting projects.

One intriguing question at the beginning of the Space Age was whether astronauts who went to the moon would sink into what was believed to be a deep layer of dust coating the surface.

He and Caltech scientist Bruce Murray decided they could answer the question using a telescope fitted with an infrared detector to analyze emitted radiation. Loosely aggregated dust, they concluded, would emit much less radiation than solid rock. Ultimately, they demonstrated that the astronauts would be safe.

In 1973, Mr. Westphal built a highly sensitive silicon-intensified target camera for the 200-inch Hale Telescope at Palomar that was 20 times more sensitive to light than the photographic film then being used.

When he and astronomer Jerry Kristian hooked it up and pointed the Hale at the Milky Way, the pattern of stars was so unusual that Kristian thought the telescope was pointed in the wrong direction. In actuality, they were seeing thousands of stars that were too faint to have been observed before. The camera is in the National Air and Space Museum.

Mr. Westphal also was intrigued by a newly developed light detector, called the charge-coupled device, being developed by NASA for the Galileo spacecraft's mission to Jupiter.

He and Caltech astronomer Jim Gunn recommended that such devices be used on the Hubble's Wide-Field and Planetary Camera. Mr. Westphal became the principal investigator for the development of the camera. That proved to be a 17-year project that Mr. Westphal said earned him "1.6 million frequent-flier miles on American Airlines" for attending innumerable meetings.

Ultimately, the scientists also were able to get the devices installed on the Hale Telescope, giving it the sensitivity of a 2,000-inch mirror using photographic plates.

Survivors include his wife, Jean; a son; two stepdaughters; and two granddaughters.

James Westphal devised tools for astronomy and geology.