Telescope bend

The bending of a large astronomical telescope by gravity is called telescope bending . It is counted among the instrument errors, can reach the order of magnitude of arc seconds and influences the exact measurement of elevation angles .

The influence increases with the sine of the zenith distance and is therefore symmetrical to the zenith . As a result, telescope bending (along with other instrument errors) is eliminated when two opposite stars are observed at the same height.

Such pairs of stars are measured u. a .:

• with the Horrebow-Talcott method for determining latitude
• with the Sterneck method for determining latitude
• at the time. and length determination with the passage instrument
• with the method of equal heights
• and other types of astro-geodetic simultaneous measurements .

While in astrometry and geodesy this effect is minimized by the measuring arrangement, considering him observatories already software in the computer control of large telescopes .

With zenith telescopes and zenith cameras , the telescope bending is almost zero, which is one of the advantages of this group of instruments.