SU1762132A1 - Method of adjustment of photometer - Google Patents

Abstract

Usage: photometry, with the adjustment of photometers, mainly infrared radiation, intended for astronomical observations. SUMMARY OF THE INVENTION: An artificial light source is moved in the plane of the entrance pupil, an area where there is no photodetector signal is detected, and the photoreceiver unit is displaced perpendicular to the optical axis in a direction parallel to the direct center of the input meter of the photometer until the signal appears photodetector at any position of a point source in the plane of the entrance pupil.

Description

The invention relates to photometry and can be used in the alignment of photometers with predominantly infrared radiation, designed to measure the weak radiation fluxes of astronomical and other objects.

A technical solution is known in which the photodetector and the Fabry element placed in the cooled volume of the cryostat are pre-centered and then adjusted by rotating the cryostat along two coordinates around the focus point of the telescope with which the Fabry lens is aligned. For adjustment, the signal from the star is recorded at various positions of the cryostat, and, choosing the maximum signal from all the signal values, the cryostat is fixed to the position corresponding to it.

However, the maximum of the signal observed when the cryostat turns is rather flat. Therefore, the accuracy of the adjustment of the photometer is low.

To improve the accuracy of the alignment, after the maximum signal was found, an additional photometer diaphragm was scanned with the image of a star in two mutually perpendicular directions while simultaneously recording the photodetector signal. By shifting the cryostat, both recorded signals are symmetrical.

The disadvantage of the described method is its low accuracy, limited by the stability of the atmosphere, the possibility of its use only at night under good weather conditions.

The aim of the invention is to improve the accuracy of the adjustment.

This goal is achieved by the fact that in the method of adjusting the photometer, designed primarily for astronoV |

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In the infrared region, which consists in displacing the photoreceiver unit before receiving the image of the entrance pupil of the photometer on the photodetector, an artificial point source of light is moved in the plane of the entrance pupil, the area where the photoreceiver signal is missing and the photodetector perpendicular to the optical axis is displaced a direction parallel to the straight line connecting the center of the zone with the center of the entrance pupil of the photometer until the photoreceiver signal appears at any position of the point source in the plane entrance pupil.

The process of adjusting the photometer is as follows.

A small radiation source (probe) is required for adjustment. In the simplest case, an incandescent lamp can be used as a probe. It is possible to use a group of switchable probes, which will significantly speed up the process of adjustment. It is also necessary to have a device that allows the probe to be fixed at an arbitrary point of the entrance pupil of the telescope. In the simplest case, this may be a guide or several guides.

The probe brightness should be sufficient for it to be surely fixed by the photodetector.

Installing the probe in the center of the entrance pupil of the lens, Offset of the photodetector, Fabry element or other optical elements of the photometer is achieved by the presence of a signal from the probe.

By gradual movements of the probe, a zone is determined, the signal from which is detected by the photodetector. We make the adjustment of the photometer, the offset of the photodetector unit, or other elements of the photometer. The direction of displacement is determined by the position of the dead zone relative to the center of the entrance pupil. Its value can be determined by the formula

D D R, where D is the offset of the photoreception.

Nick, D R - the size of the dead zone in the direction of displacement, the RF - the focal length of the Fabry element, P 0b - the focal distance of the lens.

The correctness of the adjustment is determined by the absence of dead zones at the entrance pupil of the objective lens.

Since, in this case, radiation from any point of the entrance pupil hits the photodetector, the photometer is balancing.

The accuracy of the adjustment of the proposed method is limited by the size of the probe and the discreteness of its installation. It can be calculated by the formula T (%)

5 „R + REST. 100% 1 Where D3 is the diameter of the probe.

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Dyer - installation resolution, D06 - lens diameter.

Thus, this method of adjusting the photometer provides an increase in the accuracy of the adjustment, gives its numerical evaluation, is convenient in operation due to the possibility of performing the adjustment in the daytime under any weather conditions, ensures the optimal matching of the photodetector and the power optics.

Claims (1)

The invention is a method for adjusting a photometer, primarily intended for astronomical observations in the infrared region, which consists in displacing the photoreceiver unit until an image is received on the photoreceiver. 5 of the pupil of the photometer, characterized in that, in order to improve the accuracy of the alignment, the artificial point source of light is moved in the plane of the entrance pupil, determine the zone where the photodetector signal is absent, and shift the photoreceiver unit perpendicular to the optical axis in a direction parallel to connecting the center of the zone with the center of the entrance pupil of the photometer to the left of the photodetector signal at any position of the point source in the plane of the entrance pupil,