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Transit Telescope

A Transit Telescope is the basic instrument for determining time by stars. It is fixed such that the instrument rotates on its axis in a north-south plane.1 An observer using the transit telescope watches a chosen star pass across the cross-hairs. These time measurements probably provided time base for the Haish telescope in the Goodnow observatory and did provide time for the Rock Island railroad. This Fauth Transit Telescope was purchased by the college in 1888 for a concessional price of $550.   The transit telescope (in Noyce Hall foyer), chronograph (in display case F2), astronomical Seth Thomas clocks (in Kistle Science Library), and micrometer (in case F2) were purchases requested by Samuel J. Buck following the construction of the Goodnow observatory with its Haish telescope. “If a man makes you a present of a fine horse, immediately you begin looking about for a saddle and bridle, harness, carriage and sleigh in order to make use of the horse,” The transit telescope is the basic instrument for determining time by stars. The axis of a transit telescope is fixed in the east west direction so that when the instrument moves, it moves only up and down in a north-south plane. This one was mounted on a Y shaped metal base and located in the brick transit house just East of Goodnow. It was reported to have an objective with aperture of 3 inches and three eye pieces, a direct, diagonal, and a nadir, with approximate powers of 50, 100, and 30, respectively.  An observer would watch a chosen star pass across the cross-hairs. The time between one passage of a star and the next is one sidereal day. The interval between two successive passages of the sun past some fixed point in the sky, such as the meridian, is one solar day, and it is 3 minutes 56 seconds longer than the sidereal day. Because the observations of stars are made at night, the cross-hairs must be illuminated. The cross-hairs are in the center of the telescope tube, and a window at each end of the support admitted light from a kerosene lamp to make the cross-hairs visible. From a knowledge of the longitude of the observatory and the location in the sky of a particular star, one can calculate precisely the time at which that star passes the local meridian. If the passage is observed with the transit telescope, the derived time can be used to set a clock or, more likely, produce a correction to be applied to the clock’s reading. It is easier to use corrections than to set clocks frequently.

Goodnow Hall

Located on the Grinnell College campus and constructed in 1885, Goodnow Hall was the first building constructed after the devasting tornado of 1882. Goodnow was built with quartzite rock, at the time a rare material.  The architect was Stephen C. Earle;  E.A. Goodnow provided the $10,000 required for the construction.   Initially designed as a library and observatory, it became the home of the physics and mathematics departments following the construction of the Carnegie library in 1904.  A wooden cornice from the original library is on display in the Physics Museum The dome on the tower of Goodnow housed the Hsieh telescope, an Alvan Clark eight-inch refracting instrument.  Two precision Seth Thomas clocks, one set on sideral time and the second on solar time, in conjunction with a Fauth transit telescope, a Fauth chronograph,  provided accurate timekeeping.  The eight-inch objective lens on display in the museum is the only remaining remnant of the telescope. The small transit hut with the slotted roof beside Goodnow contained the transit telescope with telegraph connections to the Goodnow clock room with its two precision clocks and chronograph.  All are on display in the museum.  The Warner-Swasey filar micrometer used with the Hsieh telescope is also displayed in the museum. In 1926 leakage problems forced the removal of the tower observatory dome and astronomy disappeared from Grinnell's curriculum until the 1960's.  The current Grant O. Gale observatory with its 24-inch telescope was dedicated in 1984. After the physics department moved to the new Science Building, Goodhow housed the psychology department from 1954 until 1988.  Following a major restoration project in xxx which included replacing the limestone belts on the tower, the anthropology department moved to Goodnow.  In 2019 after the anthropology department moved to the new Humanities and Social Sciences Center, Goodnow awaits its next occupant.

Canon PowerShot A95 Camera

The A95 compact digital camera with 5 megapixels and made in China was first marketed in 2004 by Canon Inc. The camera has 3x zoom lens with specifications of 7.8 - 23.4mm and 1:2.8-4.9.