Images(2)

astronomical transit

Date1874-1905

Inventory Number1997-1-1808

ClassificationTransit

Subject

Maker Fauth & Company 1874 - 1905

Cultural Region

Place of Origin

Dimensions130 x 100 x 60 cm (51 3/16 x 39 3/8 x 23 5/8 in.)

Material

Accessoriesbubble level

DescriptionThe heavy base of this instrument as four leveling screws. The lever with a wooden handle is used to lift the instrument out of its mount. A smaller lever, just on top of it, does the same but for smaller heights.

Two large pillars support the telescope. The latter pivots on a system of bearing wheels, found on each pillar, which have a counterweight to adjust the amount of pressure given by the telescope on the bearings. Each side of the telescope has a graduated circle with reading lens. One side has a bubble level and the reading is fixed to a vernier, which appears blank. The other side is similar, though the graduated circle is made of a silvered line. The vernier is clearly seen and it also has a tangent screw for precise positioning. A bubble level with a rectangular mirror (so one could see the lines when they are underneath) was also added on this side.

The telescope's optics is still very good. Protective caps are found at each end of the telescope. On the base, finally, a large bubble level can be put on top of the transit to level it. Was used in conjunction with the leveling screws.

Signedon eyepiece mounting: Fauth & Co Wash'n D.C.

FunctionAn astronomical transit is used with a clock to measure the altitude and time that a star or celestial body crosses the meridian at a specific location. This gives the declination and right ascension of the star, which are that star's coordinates in the sky. The information can also be used to find the longitude of a location if one has knowledge of when the meridian crossing would happen at the zeroth longitude.

If one has a table listing when a particular star is to cross the meridian at a given location, one can use the transit to find the time at that location at that moment. For this reason, small table top transits were often used by watchmakers to check the running of their watches and clocks.

Medium-sized and larger portable transits (like this one) were used in the field by astronomers when they went on expeditions to observe an eclipse or Transit of Venus.

ProvenanceFrom Harvard College Observatory.

Historical AttributesUsed at Harvard College Observatory