scintillometer (sintilometer)

[L. scin till a, a spark, + Gr. μέτρον, measure.] An instrument devised by Montigny for measuring the intensity of scintillation of the stars. The apparatus consists e entially of a circular gla plate mounted obliquely axis and in front the eyepiece of a telescope. An opening in the center of the plate allows the insertion of a ring, through which pa es the axis, parallel to the optical axis of the telescope scioptic and at a distance from it of about twenty-five millimeters. The plate is rotated about the axis by a mechanism. By this device, the rays of light from a star are refracted through the inclined gla plate, and the image describes a perfect circle in the field. If the star undergoes no change, the circumference is a continuous line exhibiting the color of the star; but if the star scintillates, this circumference is divided into fugitive arcs of different colors. The number of changes of color per unit of time indicates the intensity of the scintillation.