• Webster's Revised Unabridged Dictionary
    • n Astrometer An instrument for comparing the relative amount of the light of stars.
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Century Dictionary and Cyclopedia
    • n astrometer An instrument designed to measure the relation, brightness, or apparent magnitude of the stars. It was invented by Sir John Herschel. By it an image of Jupiter, the moon, or some other object of recognized brightness is brought into direct comparison with a star, so that star and image are seen in the same direction. By adjusting the distance of the image so that it appears equal in brightness to the star, and by measuring this distance, the luster of the star is readily determined.
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Webster's Revised Unabridged Dictionary
Astro-, + meter,


In science:

DoPHOT (Schechter, Mateo, & Saha 1993) was used to get the field star positions to make an “internal” astrometic catalog from our own images.
CfA3: 185 Type Ia Supernova Light Curves from the CfA
We made further IR observations of this source with the Magellan 6.5 meter Baade telescope using the Classic Cam instrument on January 23, 2003, but we were not able to analyze the data because of difficulties with the astromet ry of the images.
IR and Optical Observations of GRB 030115