12-inch equatorial refractor
Astronomy
Optical instrument
Telescope
Measuring instrument
The telescope is a refractor with an objective of 12.4 inches clear aperture and of 15 ft. focal length. The objective is by J.A. Brashear of Allegheny, the curves used being those of Professor Charles Hasting. The objective is a doublet, or achromatic lens. Brashear used postage stamps to separate the two elements. The cell did have a small plate saying “J.A. Brashear, Allegheny Pa.” Brashear-Hasting objectives had the flint in front design. Flint is not typically the front lens because it was thought to be more susceptible to atmospheric attack and scratches. Hastings showed otherwise.
The telescope has a German equatorial mount on a rectangular cast-iron column of two-tons weight. The polar and declination axis are cylinders of steel three-inches in diameter. The tube consists of seven cylinders riveted together, six of 2.5 ft length and the seventh somewhat shorter. The sheets of steel composing the cylinders are 1/16 to 3/32 inches thick.
Two large graduated circles help with positioning the instrument. The right ascension wheel is 18.1 inches in diameter, graduated to 5 minutes. The declination wheel is 30 inches diameter graduated to single degrees for the same purpose in declination. The graduation marks of these coarse circles are streaks of white paint on a black back ground and are easily legible from the eye end of the tube in any position of the instrument. There exists a vernier scale for the right ascension but it is not longer operational. The vernier scale in declination is still operational and read from the eyepiece end of the telescope through 2 brass tubes. On the eyepiece of the declination reading telescope is marked "Gundlach Optical Rockchester NY."
The instrument is further provided with a driving clock. The original was replaced in the 1954 with a motor driving drive. Slow motion in both right ascension and declination was achieved by hand turned knobs at the eyepiece end of the telescope. Currently they are operated by electric motors. Right ascension and declination clamps are brought to the eyepiece. On the north side of the pier is a sidereal dial (clock work missing) and a wheel for coarse motion in right ascension.
The helioscope or finding telescope is 3.2 inches aperture and 4.5 ft. focal length, also by John A. Brashear. It has a brass tube and accepts 1 ¼ inch eyepieces.
The telescope came with a filar micrometer (see below), 6 negative eyepieces, 1 zenith prism, 1 helioscope (finder) and the plate camera (see below). Added 8 weights and bracket in fall 1911, also worked on the worm. According to Warner & Swasey, it was designated M-42, two other telescopes of this type were sold to Dudley Observatory in New York and American University in Beirut, Syria. The Dudley Observatory telescope is currently in storage.
The telescope was assembled in November 1896. In a March 6, 1897 letter to President Draper, director G.W. Myers noted “The equatorial room, not having been finished on the interior, the unpainted interior surface of the wooden dome is continually exposed to the moisture of the air, which causes the dome to become deformed so seriously during damp weather as to make it well nigh impossible to mange it for several days thereafter. The open condition of the room also contributes seriously to the difficulty. Under present conditions, the $5000 equatorial must necessarily injure rapidly from exposure. Half a dozen times since the instrument was mounted last Nov. a sheet of ice chrystals [sic] has formed over the lens from the excessive moisture of the room, so thick as to render observations temporarily impossible. This condition of things must injure the lens in time if not obviated.” Money was appropriated to paint and caulk the room.
“When the writer (Joel Stebbins) took charge of this Observatory in 1903, he found that the 12-inch objective had not given satisfaction for some years. The out of focus image were elliptical, and with good seeing the definition was rather poor. However, the lens was far from useless, and it seemed best to go ahead with the program of double stars, most of which were easy objects for an instrument of this size. During the summer of 1905, the writer was to be absent from the Observatory, and the lens was shipped to Allegheny at the request of Mr. Brashear, who naturally became interested when he learned that an objective of his manufacture was not giving satisfaction. He found that the metal ring which holds the lenses in the cell had been pressed down on one side, and allowed to remain, causing a permanent bending, principally of the flint lens. Although he was in no way responsible for this occurrence, Mr. Brashear kindly refigured both lenses without cost to the Observatory, and the objective was returned in October 1905. The defects were corrected, and now we have a first class objective.”
The telescope was restored in 1953 by J.W. Fecker Inc. for $15,000. The telescope was disassembled about April 10, 1953 and sent to Pittsburgh. It was returned later that summer using a better quality crane than the one used to remove the telescope. At that time, the gravity driven drive, the manual slow motion controls, the right ascension vernier scales, and the right ascension friction wheels were removed and the telescope was updated with electric motors. The dome motor was also replaced. In the late 1980s, members of the astronomy club cleaned the recent paint off the telescopes’ brass tail piece and improved the telescopes’ electronics.
The telescope was restored for a second time during the summer of 2013 by Ray Museum Studios of Swarthmore, Pa.
Warner & Swasey Company, Cleveland, Ohio and
John Brashear, Allegheny, Pennsylvania.
Stebbins, J. Photometric Observations of Double Stars. The University Studies. Vol. 2, no. 5. July 1907. University of Illinois Press.
Myers, G.W. (1898) The Astronomical Observatory. Technograph. 11: 105-111.
Astronomy Department, University of Illinois, Urbana, Illinois
1896
Michael Svec
copyrighted by Michael Svec
image/jpg
English
physical object
University of Illinois Observatory collection A101, A105
University of Illinois Observatory, Urbana, Illinois
Visual polarizing photometer
Astronomy
Measuring instrument
Optical instrument
Photometer
Wood, brass, glass
Wooden box with hinged lid, barlow adapter, brass ring. Box measures 30” x 9” x 9”. The photometer is 24” long.
The visual photometer utilizes the polarizing properties of doubly-refracting crystals to measure stellar magnitudes. It is used on double stars where one of the stars has a known magnitude.
“The polarizing photometer used in these observations was constructed by Alvan Clark & Sons. It is of the form devised by Professor Pickering and described by him in Annals of Harvard College Observatory, Vol.11, page 4, where it is designated as ‘Photometer H’. A Wollaston prism forms two images of each star, and these images are varied in intensity by rotating a Nichol placed between the eye and the eyepiece. . . This instrument is capable of extremely accurate results, bit its use is limited to those stars which are closer than about 100”"
Used by Stebbins to observe double stars in 1904-06 and Delta Cephei in 1907 leading to pioneering work by on measuring brightness using electricity making visual photometry obsolete. After Stebbins left in 1922 with the photoelectric photometer, C.C. Wylie resumed using the visual photometer to study WW Aurigae and Delta Cephei. It was used in the 1950s and early 1960s for instruction after a cleaning by J.W. Fecker in 1954. In 1957 Robert Tull and in 1961 Robert Roeder prepared instructions on the photometer’s use.
Alvan Clark & Sons
Stebbins, J. (1907, July) Photometric observations of Double stars. The University Studies, vol, 2, no. 5. University of Illinois Press.
Stebbins, J. (1908). The light-curve of δ Cephei. Astrophysical Journal, 27, 188-193.
Wylie, C.C. (1925). Note on the eclipsing variable WW Aurigae. Popular Astronomy, 33:600-601.
Report of observatories. (1924). University of Illinois Observatory. Popular Astronomy. 32:98-99.
Astronomy Department, University of Illinois, Urbana, Illinois
1899
Michael Svec
copyrighted by Michael Svec.
image/jpg
English
physical object
University of Illinois Observatory Collection A131
University ID 016670, obs 66
University of Illinois Observatory, Urbana, Illinois
3-inch combined transit and zenith telescope
Astronomy
Optical instrument
Measuring instrument
Navigation
Surveying
Metal, glass
The principle transit circle was a 3-inch Combined Transit and Zenith telescope designed by Warner & Swasey especially for Illinois. The objective, by John Brashear, was held in place by a special cell that compensated for the different temperature conductivities of the brass and glass so that temperature had no effect on the location or separation of the lenses. Designated as model M-505, the transit includes a handing level, micrometer with a reticle contained a series of 5-3-5-3-5 parallel lines etched onto glass, and a built in reversing mechanism. This transit was located in the east-central transit room allowing direct access to the clock room through a small window. A basin of mercury (mercury now removed) in the base of the transit was used for vertical collimation and nadir observations. Marked with a Warner & Swasey plaque and a smaller J.W. Fecker plate added after the April-June 1953 restoration.
The transit circle was capable of determining both right ascension and declination. Installed February 20th 1897 and dismounted in 1974 because of the condition of the roof and shutter. The instrument cost $1200, and was the first of five 3" combined transit and zenith telescopes. Additional M-505 were built for Park College (1897), Warner & Swasey Observatory at Case Western Reserve University (1898), Lafayette College in Easton PA (1906) and the Elgin Watch Company in Illinois (1909). The Park College telescope was stolen in the late 1980s and the observatory no longer exists. The Traill Observatory at Lafayette College was torn down in 1929 and Warner & Swasey Observatory in Cleveland is abandoned. The transit was featured in Warner and Swasey’s 1900 portfolio “A Few Astronomical Instruments.”
Myers’ description of the instrument: "The combined transit and zenith telescope has a Brashear objective of three inches diameter and a focal length of 37 inches. It has two graduated circles, one of 12.5 inches diameter, graduated to half degrees and read by verniers to minutes, and the other of 12 inches diameter, graduated to 10 minutes and read by verniers to 10 seconds. Delicate striding and zenith telescope levels, together with a micrometer that may be used either in right ascension or declination render the instrument capable of yielding very excellent data whether used as a transit instrument or as a zenith telescope.
“The larger part of the weight of the horizontal axis, which by reason of its system of circles, levels, etc., is subject to considerable flexure, is borne by a pair of friction rollers, held by springs against cylindrical bearings at either end and about 2 ½-inches within the pivots. Only enough weight is allowed to come upon the pivots to make them rest firmly in the wyes.
“By suitable combination consisting of a level, a graduated circle and a reversing apparatus the west pivot may be brought into the east wye and the instrument reset upon the same star with extreme quickness and perfect safety. In addition to the above mentioned facilities, the instrument is supplied with a mercurial horizon, a complete set of eye pieces, including a collimating and a zenith eye piece. All in all, this instrument leaves little to be desired in either point of convenience or of completeness."
One of Warner & Swasey’s most important achievements was the construction of a Dividing Engine in 1880 for automatically graduating circles of 40-inch or less in diameter. The greatest errors made by this machine were less than one second or arc. This instrument was used to make the vernier scales for all of their telescopes and transit telescopes including both the Illinois transit and equatorial. Warner & Swasey built a 6-inch transit circle for the U.S. Naval Observatory in 1898 and remained a premier astrometry instrument for almost a century.
C.M. Huffer remembered using the transit in the course Practical Astronomy about 1916 for the determination of time and position. Astronomy club president F. Samuel Bauer remembers that in 1962 "Equinoxes were a special time for students, in that they were celebrated by timing them. Using the transit instrument, an ad hoc group would fire up the shortwave radio in the timing room and get the ink flowing on the chronograph, with the WWV signal providing timing blips. Other members would use the transit telescope to time the passage of a chosen star to determine the exact time of the equinox sending 'wire crosses' to the chronograph pen by telegraph key."
Warner & Swasey Company
Warner & Swasey. (1900). A few astronomical instruments. From the works of Warner & Swasey, Cleveland, Ohio. Warner & Swasey: Cleveland.
Myers, G.W. (1898) The Astronomical Observatory. Technograph. 11: 105-111.
Astronomy Department, University of Illinois, Urbana, Illinois
1896
Michael Svec
Copyright Michael Svec
image/jpg
English
physical object
University of Illinois Observatory Collection, A110
University ID 016647
University of Illinois Observatory, Urbana, Illinois
Filar micrometer
Astronomy
Measuring instrument
Optical instrument
Wood, brass, glass
Wooden box (dimensions) with hinged lid, with 4 colored shades (2 green, 2 red), 3 eyepieces with adapter, one smaller eyepiece with adapter, accessories for light.
“Its filar position micrometer consists essentially of a position circle 6.3 inches in diameter, graduated on silver to half degrees and read by to verniers to tenths of a degree and a very accurately threaded screw, carrying a light frame holding the micrometer wires. Whole revolutions of the screw are read by a toothed wheel and fractional parts of the screw are given by a drum of 2.5 inches diameter whose circumference is graduated to hundredths. Tenths of divisions are readily estimated. The micrometer box is moveable in position angle, the entire system of threads fixed and movable is carried ‘in distance’ by a screw without graduations and the eye piece is adjusted to the center of the fields by a still different screw.”
A filar micrometer is used for precision positional astronomy by measuring the separation or angular distance between two objects. In addition it can measure the position angle between them. They were often used to measure the angles and distances between double stars. Data gathered over long periods of time could demonstrate the orbit of one star about the other star. Micrometers are seldom used on modern astronomy having been replaced by newer techniques.
This micrometer came with the Equatorial. Stebbins used it to measure size of crater Linné during February 8, 1906 lunar eclipse. Cleaned by J.W. Fecker in 1954.
Warner & Swasey Company
Myers, G.W. (1898) The Astronomical Observatory. Technograph. 11: 105-111.
Stebbins, J. (1906) Observations of the crater Linné during the lunar eclipse of February 8, 1906. Astronomical Journal. Vol. 25. No 587, p. 87-88.
Astronomy Department, University of Illinois, Urbana, Illinois
1896
Michael Svec
Copyright Michael Svec
image/jpg
English
physical object
University of Illinois Observatory Collection A102
University ID 016717, obs 735
University of Illinois Observatory, Urbana, Illinois
Visual spectroscope
Astronomy
Measuring instrument
Optical instrument
Spectroscope
Wood, brass, glass
Comes with large wooden box with hinged lid (24” x 14” x 8”), 12”tall stand (obs 726), and accessories. It includes a dense flint prism and a reflection diffraction grating. Crosshairs and a precise scale permit the measurement of position of the emission or absorption lines to an accuracy of 6.5 Angstroms with the prism and 3 Angstroms with the diffraction grating. Slow motion arm is damaged, soldering makes attaching to the stand difficult.
In Stebbins’ notebook, “One second size astronomical spectroscope with circle and slow motions, one 1-inch grating, one dense flint prism with minimum deviation, without micrometer. Final bill June 29 $200.”
“The curves are based upon the normal solar spectrum produced by a small grating spectroscope attached to the 12-inch refractor. The center of the sun’s image was kept on the slit of the spectroscope, . . . The spectroscope is a modest affair, being next to the smallest size regularly manufactured by Brashear. The ruled surface of the plane grating is 19 x 25 mm and the objectives of the collimator and view telescope are each of 19 mm aperture and 285 mm focal length.”
Cleaned by J.W. Fecker in 1954.
John Brashear, Pittsburgh
Stebbins, J. 1907. The color sensibility of selenium cells. Astrophysical Journal. 26, 326, 183-187.
John A. Brashear Company LTD. (1906). Catalogue: Optical, physical, astrophysical and astronomical instruments. John A. Brashear Co. LTD.: Allegheny PA.
Astronomy Department, University of Illinois, Urbana, Illinois
1907
Michael Svec
copyright by Michael Svec.
image/jpg
English
physical object
University of Illinois Observatory Collection A132
University ID 016671, obs67
University of Illinois Observatory, Urbana, Illinois
Plate camera
Astronomy
Photography
Camera
Optical instrument
Wood, brass
Wooden box (9 ½ x 9 ½ x 9) with hinge lid, two film holders, several 3-inch x 3-inch glass filters. The plate camera is an original piece of equipment made by Warner and Swasey. It takes 2 ¼-inch by 3 ¼-inch glass plates or sheets of film. There is an off axis guider that accepts 0.69” eyepieces and the plate carrier can be rotated by 180 degrees. There are two lateral screws (90 degrees apart) that can be used for tracking by moving the film instead of the telescope. The instrument is still located in the Observatory and is usable.
In the 1950s and 1960s it was used for instruction. There are approximately 270 plates from this time period in the Astronomy Department.
Images include the envelope, calibration plate, and image of the Moon taken on February 21, 1975 by Jim Wehmer. The glass plates were Kodak 103a-E film. The original plates are in the possession of Jim Wehmer and are shared here with his permission.
Warner & Swasey Company
Astronomy Department, University of Illinois, Urbana, Illinois
1896
Michael Svec
Copyright by Michael Svec
image/jpg
English
physical object
University of Illinois Observatory Collection A106
University of Illinois Observatory, Urbana, Illinois
2-inch altitude-azimuth universal telescope
Astronomy
Navigation
Surveying
Measuring instrument
Optical instrument
Wood, metal, glass
Stored in 2 large wooden boxes (22 ¼ x 12 ½ x 14 ¼ and 22 x 22 ½ x 17 inches). Transit consists of base with three leveling screws, telescope, striding level, 3 eyepieces, several lens caps for the eye pieces and an objective light shield. Silver vernier scales are tarnished, brass reading microscopes and micrometers are pitted in places, black paint on telescope tube also pitted. Three spirit levels on base (two perpendicular to telescope one parallel) all functional. Inscribed “Troughton and Simms London” on the support for the horizontal tangent screw and “obs 62” on base by the reading microscope A.
Myers’ description of the instrument: "This instrument was made by Troughton and Simms, has an aperture of 2-inches and a focal length of 20-inches. Its horizontal and vertical circles are each 12-inches in diameter, graduated on silver to 5 minutes and read by two reading microscopes to single seconds. Tenths of seconds are readily estimated. It is provided with both fine and coarse levels for adjustment to place, an accurate striding level, and a very complete set of eyepieces. The reticle consists of nine vertical and three horizontal cross hairs, illuminated by a lamp at the end of the axis. Both vertical and horizontal circles shift for position, this instrument being the first to have a shifting vertical and among the first to have a shifting horizontal circle."
Article describing the theodolite from 1882: “A theodolite, constructed by Troughton & Simms, of London, at a cost of about $700, has been added to the equipment of the Civil Engineering Department. It is an ‘Altitude and Azimuth’ or ‘Universal’ instrument; that is, both vertical and horizontal angles can be read with it. It is the finest and best form of the most accurate engineering instrument that has, as yet been made, having all the most modern improvements. The two circles - the most important part of the instrument - are twelve-inches in diameter and graduated to five-minute divisions. Upon each, the further reading is effected by the help of two micrometers and verniers, directly to seconds; each circle may be shifted between sets of observations, and by thus reading the angle on different parts of it, any error in the graduation is thus eliminated. The telescope is superior to either of the two now in the Observatory. It was intended to mount the theodolite permanently in the Observatory with the other instruments, but the manufacturers have send a tripod, and now the instrument may be used at any point desired.
“The money, with which to buy this instrument, was appropriated in 1871, but when taxes were abated in Chicago, after the fire, the appropriation for the new building was cut off, and this money was used in its place. In 1873, another appropriation was made, but for some reason the matter was dropped until last May, when a third appropriation was made. In July an order for the instrument was send to London, and it was completed and shipped about January 1, of this year. The theodolite is to be used in the classes in Geodesy and Practical Astronomy."
This instrument was used to observe the December 6, 1882 transit of Venus across the Sun.
A 1954 survey of the instruments by J.W. Fecker Inc. noted “This instrument is in poor condition as a result of extreme neglect and many small parts appear to be missing. The considerable expense involved in reconditioning this unit might be inadvisable unless an immediate need existed for the instrument. We suggest that no reconditioning be undertaken in the absence of such need. We do recommend that the instrument be carefully reconditioned as to finish only by interested and capable students and then used temporarily as an exhibit item in the observatory entrance foyer.”
Troughton & Simms, London
Myers, G.W. (1898) The Astronomical Observatory. Technograph. 11: 105-111.
The New Theodolite. April 1, 1882, The Illini, p. 10.
Transit of Venus. December 9, 1882. The Illini, p. 8.
Astronomy Department, University of Illinois, Urbana, Illinois
1883
Michael Svec
Copyright Michael Svec
image/jpg
English
physical object
University of Illinois Observatory Collection A113
University ID 016648, obs 62
University of Illinois Observatory, Urbana, Illinois
Sextant and artificial horizon
Astronomy
Navigation
Surveying
Measuring instruments
Wood, metal, brass
Hinged box with lock, missing handle, inside lined with green felt, green paper Newton label. University tag crossed out in pen.
Sextant valued in 1908 estimated $50. Engraved on arc “Newton + Co 3 Fleet Street London.” Black metal frame, wood handle, silver scale. Includes 4 brass telescopes, 1 eyepiece cover, scale is 8” in radius, 4 index shades, 3 horizon shades, vernier read with eyepiece.
The artificial horizon:
Hinged box with two hooked latches. Exterior marked with university ID tape, old paper sticker with number 1 and more modern paper tag “7 (no Hg).”
Contained green metal shield with glass, engraved with direct, tray with some corrosion, and metal bottle.
Newton & Company, London
Astronomy Department, University of Illinois, Urbana, Illinois
circa 1872
Michael Svec
Copyright Michael Svec
image/jpg
English
physical object
University of Illinois Observatory Collection A118.1, 118.2
University ID 016653, 016653B, obs13
University of Illinois Observatory, Urbana, Illinois
Sextant and artificial horizon
Astronomy
Navigation
Surveying
Measuring instruments
Wood, metal, glass
Metal black frame with wood handle and silver scale. Horizon mirror is broken, includes 4 index filters, 3 horizon filters, 3 brass telescopes, 2 lens caps, wooden handle, 6” radius on scale, maker and model 4323 marked on index arm, vernier read by magnify lens.
Box is 9 5/8” x 9 5/8” x 5 ¼” with hinge top, two latches, lock, marked “obs 14,” with metal handle.
Acquired in exchange for small Fauth chronograph. Saegmuller joined Bausch and Lomb. In 1905, the company included all three names until 1907.
The artificial horizon:
Wood, metal, glass
In the Astronomy department is the box with the cover, marked Fauth & Co. Box is 8 3/8” x 6 ¼” x 5 ¾”, dove tails visible, 2 hook latches, exterior university id tag plus paper label #6 .. Both the tray and bottle are corroded. Wind shield is greenish metal and glass. A
The artificial horizon was used with sextant to determine the altitude of objects when the true horizon was not visible. They most commonly consist of a trough, bottle with mercury, and a wind shield consisting of two panes of glass at right angles to the observer’s line of sight. It was used by viewing the sun or star directly and then again in the reflection of the mercury surface. You would then have two measurements can could divide by two. In the Saegmuller catalog (page 63) it cost $30.
Bausch, Lomb, Saegmuller Company and Fauth Company
Astronomy Department, University of Illinois, Urbana, Illinois
1906
Michael Svec
Copyright Michael Svec
image/jpg
English
physical object
University of Illinois Observatory Collection A119.1
University ID 016654, obs14
University of Illinois Observatory, Urbana, Illinois
Double frame bridge sextant
Astronomy
Navigation
Surveying
Measuring instruments
Wood, metal, glass
Fitted keystone wood box with hinged lid and two hook latches. Black metal frame with brass screws, silver scale and wood handle. Includes 3 black painted telescopes, 1 eyepiece cover, 8-½ inch radius, eyepiece to read vernier, signed on brass radius “M. Berge London.” Matthew Berge worked in London 1800 until his death in 1820. Since it was not listed by Stebbins in 1906 and considering its age, this might be a later donation to the department.
Matthew Berge, London
Astronomy Department, University of Illinois, Urbana, Illinois
pre-1820
Michael Svec
Copyright Michael Svec
image/jpg
English
physical object
University of Illinois Observatory Collection A232
University of Illinois Observatory, Urbana, Illinois