Field of view Sentence Examples
Instruments have been invented by Alvan Clark and Sir Howard Grubb for measuring with the spider-line micrometer angles which are larger than the field of view of the eyepiece.
A faint light being thrown on the outside of the silvered plate, there appear bright lines in the field of view.
Thus, if the star's image is kept in bisection by the wire, both star and wire will appear at rest in the field of view.
Then if the prism P4 is cemented to P3, a sharp image of such lines of the solar spectrograph as are visible in the field of view will be seen in the eyepiece.
In order that a large part of the field of view may be in focus at once, it is desirable that the locus of the focused spectrum should be nearly perpendicular to the line of vision.Advertisement
Supplementary to the preceding was the Nova litteraria Germaniae collecta Hamburgi (1703-1709), which from 1707 widened its field of view to the whole of Europe.
Directing the finder to the comet, he has at once in the field of view all available comparison stars.
When the scales and position-circle of the heliometer have been set to these readings, the comet and the selected comparison-star appear together in the field of view.
But it was not till about the middle of the 17th century that Kepler's telescope came into general use, and then, not so much because of the advantages pointed out by Gascoigne, but because its field of view was much larger than in the Galilean telescope.
The eye-pieces or oculars through which, in case of visual observations, the primary images formed by the objective are viewed, are of quite secondary importance as regards definition in the central portion of the field of view.Advertisement
The mere size of the apparent field of view depends upon obtaining the oblique pencils of light emerging from it to cross the axis at the great possible angle, and to this end the presence of a field-lens is indispensable, which is separated from the eye-lens by a considerable interval.
Thus, any fixed telescope directed towards the mirror of a properly adjusted coelostat in motion will show all the stars in the field of view at rest; or, by rotating the polar axis independently of the clockwork, the observer can pass in review all the stars visible above the horizon whose declinations come within the limits of his original field of view.
When the star enters the field of view its image is approximately bisected by the spider web of the micrometer n, the exact bisection being completed in the immediate neighbourhood of the meridian.
Each of the four co-ordinates, n', x', y are functions of %, rj, x, y; and if it be assumed that the field of view and the aperture be infinitely small, then, n, x, y are of the same order of infinitesimals; consequently by expanding ', ii', x', y in ascending powers of E, rt, x, y, series are obtained in which it is only necessary to consider the lowest powers.
Spherical aberration and changes of the sine ratios are often represented graphically as functions of the aperture, in the same way as the deviations of two astigmatic image surfaces of the image plane of the axis point are represented as functions of the angles of the field of view.Advertisement
By revolving on this axis it follows a star in its diurnal motion, so that the star is kept in the field of view notwithstanding that motion.
In this case also the illumination must fall to zero by the vignetting of the pencils coming from objects at the margin of the field of view.
Through the large free working distance, which for certain work offers great advantages, the size of the field of view is diminished.
The result must be that the field of view exhibits a sharp border.
By choosing a somewhat broader diaphragm, so that the spectra of 1st order can pass the larger division, there arises in the one half of the field of view the image of the larger division, the other half being clear without any such structure.Advertisement
The placing of the analyser near the objective has the advantage that the field of view is not restricted, as is the case if the analyser .is used above the eyepiece.
The objective screw micrometer is, however, not sufficiently delicate, and is only used when comparatively large objects are to be measured, and especially for objects whose edges do not appear at the same time in the field of view.
Each detector had a co-aligned stainless steel collimator yielding an elliptical field of view 1 x 1.8 degrees.
The unit contains a reducing lens which restore the field of view to cover approximately the same area as standard x10 widefield eyepieces.
The field of view is 100 %, enabling accurate framing.Advertisement
Moving the eye closer to the lens of a hand-held or stand magnifier also increases the field of view.
The earlier arrangement of two lenses of the Huygenian eye-piece (see Microscope) having foci with ratio of 3 to I, gives a fairly large flat field of view approximately free from distortion of tangential lines and from coma, while the Mittenzw ?
If those personnel who normally wear eyeglasses can remove them during theodolite operations, they will obtain a greater field of view.
The field of view is 488 ft at 1000 yards and a close focus of 4 feet.
The field of view is 383 ft at 1000 yards and a close focus of 8 feet.
The field of view is 345 ft at 1000 yards and close focus at 11.5 feet.
Eye Relief- users want the best field of view possible.
They provide a field of view unobstructed by eyeglass frames.