SU1748123A1 - Telescopic lens optical system - Google Patents

Description

concavity to the space of images, with the difference between the refractive indices of the meniscus not exceeding 0.02, the difference of the coefficients of the average dispersions does not exceed 13,

The overall layout of the entire lens ensures perfect image quality within 1/2 of the field of view, which is confirmed by the mean square wave aberration over the spectral interval, the field and the pupil without taking into account the curvature of the image and distortion 0, OZZA, and without taking into account the distortion - 0.033 A.

In the above calculation, the optical system of the telescope lens has the following aberrations.

The transverse spherical aberration for a point on the axis does not exceed 0.02 mm over the entire pupil over the entire spectral range. The wave aberration for a point on the axis for the main wavelength at the edge of the pupil is 0.13 A, and in the zone 0.024 A.

Wave aberration for a point on the axis in the entire spectral range does not exceed 0.1 FOR.

The coefficient of neisoplanasis is equal: the pupil edge is 0.069%, the zone is 0.052%.

Image curvature and astigmatism are:

edge floor with 30; Zt 1.29 mm; Zs (0.338 mm; Zs - Zt 0.95 mm; zone about 15; Zt 0.256 mm; Zs 0.102 MM; Zs-Zt -0.154 mm. It follows that the proposed lens has a diffraction image quality.

The drawing schematically shows the proposed device.

In the drawing, the following notation is accepted: 1 — primary concave spherical mirror; 2 - negative meniscus, facing concavity to the space of images; 3 - a positive meniscus, facing the concavity to the space of objects, on the concave surface 4 of this meniscus a specular reflective coating is applied, which acts as a secondary mirror of the objective; 5 - positive meniscus, facing inwardness to the space of objects; 6 - a negative meniscus with concavity facing the image space.

The object is at infinity, so a parallel beam of rays is incident on the primary mirror of the telescope lens. The aperture diaphragm coincides with the secondary mirror. After passing through all the components of the optical system of the telescope lens 2 - 6 in the back focal plane of it, located at an SF distance of 150 mm, we obtain an image of the object.

As a concrete example, the optical system of a telescope lens is calculated with the following optical characteristics: focal length

2200 mm; rear focal length 150 mm ;, relative aperture 1: 8; angular field 1a; central screening 0.31; distance between mirrors 500 mm.

An important advantage of the telescope is an improved image quality, practically diffraction on the half of the floor, a sufficiently large back focal length, small overall dimensions, a small coefficient of central screening,

which can provide not only the observation of the starry sky, but also his photographing.

Claims (1)

Claims The optical system of a telescope lens containing a concave primary mirror, a negative meniscus and a meniscus facing the concavity of an object on the outer concave surface of which a reflective coating is applied, is different because in order to improve the quality of the image while reducing the size, the negative meniscus faces concavity to the image, and the second reflective meniscus is made positive, the difference in the refractive indices of the materials of these menisci is not more than 0.005, the difference of the coefficients of the average dispersion is not more than 6, after the negative meniscus at a distance of no more than 0.16 of the focal length of the lens, positive and negative menisci are introduced, convex to each other and made of material, the refractive index difference of which does not exceed 0.02, and the difference between the coefficients of the average dispersion does not exceed 13.