At the Dudley, Hough chose a "zone"-- a strip of sky centered about a certain declination (the latitude of the celestial sphere) in which to systematically observe the stars-- and carried out thousands of zone observations with the Meridian Circle and the Transit telescope. Under his leadership, there appeared only two volumes ever published of the "Annals of the Dudley Observatory." The first provides, in unparalleled detail, descriptions and drawings of astronomical equipment of the 1860s, a description of the observatory, and a catalog of the library. The second describes the research program of an 1860s astronomer with little funding, scant assistance, and a inauspiciously located observatory.

That program centered ingenious ways to automate observation. Completing an effort launched by Mitchel, Hough developed a declinometer, an automated mechanism attached to a transit telescope for recording the declination of stars. This potential method of vastly speeding up the recording of star positions offered promise for a while, but was superseded by photography, which offered even more speed and superior accuracy. For use with the Olcott Meridian Circle, he brought into use the chronograph, the recent independent invention of several other astronomers.

The heart of the chronograph was a very accurate clock electromagnetically coupled to a pen that used the clock's signals to lay down a dashed line, with each dash representing a small fraction of a second of time. With the push button, the astronomer sent another electrical signal that interrupted this line at the precise instant he saw a star cross the meridian. So the interruption indicated the exact time the meridian was crossed much more precisely than the old method, which relied on one person listening for another to cry out at the moment the star passed the meridian, and then noting the time on the clock's face.

The chronograph would become the standard way of recording meridian circle observations of right ascension, the longitude of the celestial sphere. Hundreds of thousands of times over the next seven decades, by pushing of a button to mark a star's meridian crossing, an astronomer at the Dudley Observatory would add one more data point to an accumulating data base for mapping the heavens

Hough also brought into operation the Scheutz "computer", a pioneering machine for computation based on the ideas of Charles Babbage. Redesigning connections among the gear wheels, and giving the machine as a general overhaul, he demonstrated its usefulness to astronomy. A few print-outs made of tables for correcting astronomical observations for the atmosphere's refraction survive at the Dudley. Looking like 20th century supermarket receipts, these strips of purple print on yellowed paper are landmark artifacts of the prehistory of the information age. They are perhaps the first computer print-outs ever made of a scientific calculation. They did not, however, lead to the automation of calculation at the Dudley. The computer was used only intermittently for the rest of the century, and ultimately ended up at the Smithsonian Institution. Meanwhile, seventy five years later, the observatory's calculations were still being carried out by humans and by hand.

In another forward looking effort, Hough carried out experiments on the speed of transmission of electrical signals over wires. He was able to show that the wide disagreement among previous such speed measurement was due to a misinterpretation of the physics involved, and therefore did not reliably indicate variations in the speed of the signals themselves.

His major efforts, however, were in the field of meteorology. Growing understanding of the fact that weather was a large-scale atmospheric phenomenon was creating worldwide interest in recording barometric pressure at many sites, telegraphing the results to a central location, and plotting them as an aid to weather prediction. Joseph Henry, at the Smithsonian, would use such methods to create the nation's first weather maps.

Hough applied his mechanical talents to invent an automatic recording barometer that would perform the data collection without human assistance. His description of this device, and detailed weather records for Albany, provide the major portions of the second volume of the Dudley Observatory Annals.

In November, 1873, the trustees of the Dudley Observatory resolved that "for the purpose of increasing the funds of the Observatory by adding thereto its annual income-- All astronomical work therein and the salaries of its officers and employees except the janitor, be discontinued from and after the first day of January, next." Hough resigned within a month of that 1873 resolution. He entered the scientific machinery business in Riverside, Illinois, where he turned the self-recording barometer and chronograph that he had perfected at the Dudley into products, and also developed other instruments for recording such things as wind speed. In 1879 he returned to astronomy as director of Northwestern University's Dearborn Observatory at Evanston, Illinois. There he completed a distinguished career as a discoverer of double stars and accurate observer of the planet Jupiter until his death in 1909.

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