Objectglass sentence example
- If 2R be the diameter of the objectglass and D the distance of the object, the angle subtended by AP is E/D, and the angular resolving power is given by X/2 D sin a = X/2 R (3) This method of derivation (substantially due to Helmholtz) makes it obvious that there is no essential difference of principle between the two cases, although the results are conveniently stated in different forms. In the case of the telescope we have to deal with a linear measure of aperture and an angular limit of resolution, whereas in the case of the microscope the limit of resolution is linear, and it is expressed in terms of angular aperture.
- This lens is divided and mounted like a heliometer objectglass; the separation of the lenses produces the required double image, and is measured by a screw.
- James Bradley, on 27th December 1722, actually measured the diameter of Venus with a telescope whose objectglass had a focal length of 2124 ft.
- In these very long telescopes This last power could not be exceeded with advantage in this form of telescope till after the invention of the achromatic objectglass.
- Huygens contrived some ingenious arrangements for directing such telescopes towards any object visible in the heavens - the focal adjustment and centring of the eyepiece being preserved by a braced rod connecting the objectglass and eye-piece.Advertisement
- In these telescopes the photographic objectglass has an aperture of 13 in.
- This instrument has a superb objectglass of 72 in.