Star transit
A star transit is the passage of a star across the field of view of a telescope eyepiece.
The precise observation of star transits is the basis of many methods in astronomy and in geodesy. The measurements can be done in different ways:
- visually : accuracy 0,1" to 2" ; timing with digital clocks about 0,05–0,2 seconds;
- by CCD and other electro-optical sensors: as above, time often better;
- semi automatic instruments: photography or "impersonal micrometer", ca. 2 times better than No. 1;
- by scanning methods: astrometry satellites like Hipparcos about 0,01".
Literature
- Karl Ramsayer, 1969: Geodätische Astronomie, Vol.2a of Handbuch der Vermessungskunde, 900 p., J.B. Metzler-Verlag Stuttgart.
- Ivan I. Mueller, 1969: Spherical and Practical Astronomy as applied to Geodesy, 610 p., Fred.Ungar publ., USA
- IAU Coll.48: Modern Astrometry, Egermann, University Vienna.