Noun:

ஞாயிற்று விட்ட அளவி,

heliometer's Usage Examples:

Gill introduced a powerful auxiliary to the accuracy of heliometer measures in the shape of a reversing prism placed in front of the eye-piece, between the latter and the observer's eye.

Better determinations of the actual value came from the heliometer, and gave an angular diameter of 31' 59.

To Dollond in 1754 we owe the combination of Savary's idea of the divided object-glass with Bouguer's method of measurement, and the construction of the first really practical heliometers.

Struve's second suggestion has been adopted in nearly all succeeding heliometers.

The reading of the positioncircle of the finder is then the reading to which the position-circle of the heliometer should be set, and from the readings of the micrometerscrew he finds, by a convenient table, the proper settings of the heliometer scales in distance.

Modern heliometers made with cylindrical slides measure angles over 2°, the images remaining as sharp and perfect as when the smallest angles are measured.

2 The diameter of Venus was measured with one of these heliometers at the observatory of Breslau by Brandes in 1820 (Berlin Jahrbuch, 1824, p.

An arrangement, afterwards described, has been fitted in modern heliometers for placing the screen in front of either segment by a handle at the eye-end.

'° Wilhelm Struve, in describing the Pulkowa heliometer,' 1 made The distances of the optical centres of the segments from the eye-piece are in this method as I; secant of the angle under measurement.

"The slowest speed is given by means of a tangent screw which is carried by a ball-bearing on the flange of the telescope sleeve, whilst its nut is double-jointed to a ring that encircles the flange of the heliometer-tube.

To remedy drawback (2) Repsolds provided for the Yale heliometer an additional handle for motion in position angle, intermediate in velocity between the original quick and slow motions.