These facilities, coupled with the wide and fascinating field of research opened up by Sir William Herschel's discovery of the binary character of double stars, gave an impulse to micrometric research which has continued unabated to the present time.
0067" 40.0025" (Perrine); the micrometric observations gave the value 8.806"±0 004 (Hinks).1 II.
Considerable angles with micrometric accuracy, that he resolved, when he should have the choice of a new telescope for the observatory, to secure some form of heliometer.
P. 419) suggested the division of the small speculum of a Cassegrain telescope and the production of double image by micrometric rotation of the semispecula in the plane passing through their axis.
Fraunhofer, Dorpat, 1825), and was an enormous advance upon all previous telescopes for micrometric research.