RU184636U1 - OPTICAL TELESCOPE HOOD - Google Patents

Abstract

The utility model relates to astronomy and can be used, in particular, for conducting high-precision photometric measurements of a space object in outer space located at a small angular distance from a bright radiation source (for example, the Sun, Moon). The inventive hood is designed to protect the optical telescope from interfering illumination of third-party radiation sources and is configured to install an optical telescope on the round input aperture, and is a three-dimensional part in the form of a plate curved in one direction with a constant radius of curvature corresponding to the radius of the telescope entrance aperture, and having the upper edge with beveled corners, while the length of the lower end of the plate is equal to half the circumference of the input aperture with a valid value rejected I have no more than 5%, and the maximum height of the plate (h) is given by: h = D / tg α, where D - entrance aperture diameter of the optical telescope, α - minimum angular distance between the directions of the observed object and the source-side illumination. The technical result of the claimed utility model is to reduce the area and mass of the hood while maintaining the efficiency (level) of protecting the entrance aperture of the optical telescope from exposure to a bright astronomical source located at a small angular distance from the observed weak astronomical object. 3 s.p. f-ly, 5 ill.

Description

Technical field

The utility model relates to astronomy and can be used, in particular, for conducting high-precision photometric measurements of a space object in outer space located at a small angular distance from a bright radiation source (for example, the Sun, Moon). In particular, the utility model relates to a lens hood designed for optical telescopes.

State of the art

A semi-cylindrical hood is known from the prior art, the description of which is disclosed in patent RU 2536330 C1 (IPC G02B 23/00, G02B 17/06, published on December 20, 2014). A telescope is known from this information source, including a housing with an optical system located in it, containing a main concave hyperbolic mirror with a central hole, a secondary convex hyperbolic mirror, and a photodetector installed in the focal plane of the telescope. The casing is equipped with a semi-cylindrical sun shade mounted on the entrance pupil of the telescope with the possibility of rotation by the drive around the optical axis of the telescope. Solar photocells are installed on the edges of the inner surface of the semi-cylindrical sunshade to supply a signal to its drive. The length of the semicylindrical sun shade is calculated from the mathematical ratio and depends on the diameter of the telescope entrance pupil and the angular distance between the directions to the center of the moon’s disk and to the edge of the sun’s disk closest to the moon.

However, the semi-cylindrical hood has a large area and mass, which increases the total mass and moment of inertia of the optical telescope itself, and accordingly also requires an increase in drive power to rotate the hood.

In the prior art, a movable sunshade is known, adopted as the closest analogue-hood - US 8186628 B2 (published on 05.29.2012, B64G 1/52). The moving sunshade comprises a base, a partially conical tube reflector having a first end portion, a second end portion and a curved elongated portion located between the first and second end portions, and a visor pivotally mounted at the second end of the hood, with the first end portion being mounted rotation on a specified basis. The sunshade is configured to be mounted on the input aperture of an optical telescope and mounted at an angle relative to the aperture of the telescope. This lens hood has a smaller area compared to the previous one (from patent RU 2536330 C1). However, the patent does not indicate specific optimal geometric characteristics in which such a lens hood would have a minimum weight while protecting the input aperture of the telescope from radiation from a bright source. Moreover, the patent does not contain any data for the purpose of reducing the mass of the sun shade while protecting the input aperture of the telescope from radiation from a bright source.

The technical problem is the increase in the mass of optical telescopes intended for observing weak astronomical objects located at a small angular distance (several degrees) from a bright astronomical source (for example, the Sun), causing the input aperture to illuminate, due to the large mass of the lens hood.

Utility Model Disclosure

The technical result of the claimed utility model is to reduce the area and mass of the hood while maintaining the efficiency (level) of protecting the entrance aperture of the optical telescope from exposure to a bright astronomical source located at a small angular distance from the observed weak astronomical object. Due to the reduction in the mass and area of the lens hood and, accordingly, the entire optical telescope, the following advantages follow: a decrease in the moment of inertia of the optical telescope itself, a decrease in the drive power requirement for rotating the lens hood, etc.

The technical problem is solved due to the fact that the hood designed to protect the optical telescope from interfering with illumination of third-party radiation sources is configured to install an optical telescope on the round input aperture, and is a three-dimensional part in the form of a plate bent in one direction with a constant radius of curvature, corresponding to the radius of the input aperture of the telescope, and having an upper edge with beveled corners, while the length of the lower end of the plate is equal to half the circumference of the input ape tours with permissible deviation value of not more than 5%, and the maximum height of the plate (h ₀₎ given by the relation:

h ₀ = D / tg α,

where D is the diameter of the input aperture of the optical telescope;

α is the minimum angular distance between the directions to the observed object and a third-party source of illumination.

The plate can be made in the form of a half cylinder with beveled upper corners.

A curved plate in a flat scan has a bevel line h (ϕ) lying in a region whose lower boundary is determined by the expression h ₁ (ϕ), and the upper boundary by the expression h ₂ (ϕ), where:

h ₁ (ϕ) = h ₀ ⋅cos ϕ, [cm],

h ₂ (ϕ) = h ₀ ⋅cos ^1/2 ϕ,

-90 ° <ϕ <90 °

h ₁ (ϕ) ≤h (ϕ) ≤h ₂ (ϕ) is the height at the corresponding point of the plate,

ϕ is the angle between the radius drawn to the center point of the lower end and the radius drawn to the point relative to which the value of h (ϕ) is determined, which characterizes the height of the plate at this point.

A curved plate in a flat scan has a bevel line described by the equation

h (ϕ) = h ₀ ⋅cos ϕ, [cm],

-90 ° <ϕ <90 °

where h (ϕ) is the height at the corresponding point on the plate:

ϕ is the angle between the radius drawn to the center point of the lower end and the radius drawn to the point relative to which the value of h (ϕ) is determined, which characterizes the height of the plate at this point.

Brief Description of the Drawings

In FIG. 1 shows a general view of an optical telescope with the inventive hood (longitudinal section);

In FIG. 2 shows a top view of an optical telescope with a hood;

In FIG. 3 and 4 depict shadow areas from the lens hood in the plane of the input aperture when using the prototype — the semi-cylindrical lens hood of the optical telescope (FIG. 3) and the inventive hood (FIG. 4).

In FIG. 5 shows a reamer of the semi-cylindrical hood of the prototype telescope and the inventive hood.

The positions in the drawings indicate:

1 - telescope body;

2 - a telescope hood;

3 - drive rotation of the hood;

4 - direction sensors to the light source;

5 - lateral end parts of the hood;

6 - the upper part of the hood.

Utility Model Implementation

The optical telescope consists of a housing 1, in which an optical system with a circular input aperture of diameter D, a radiation receiver, and a control unit for transmitting information are located. The radiation receiver is located in the focal plane of the optical system. Thus, the optical system builds an image on the radiation receiver.

As an optical system, it is possible to use both classical versions with a concave primary and convex secondary mirrors, as well as other designs of optical systems with a round entrance aperture of the telescope. For example, it is possible to use the following optical systems: the Maksutov, Schmidt mirror-optical optical system, purely lens systems, the three-mirror Korsh telescope, etc. So in FIG. 1 and 2, as an optical system, a classic version with a concave primary and convex secondary mirrors is shown.

At the round entrance aperture (entrance pupil) of the telescope, a hood 2 is installed at a right angle to the plane of the aperture, which can rotate with the help of a drive 3 along the guides (not shown in the drawings) at the end of the telescope body 1 around the entrance aperture (thus, the mobility of the hood is achieved) . The axis of rotation of the protective hood 2 coincides with the optical axis of the telescope. To ensure rotation of the hood 2, the input aperture of the telescope should be round.

To select the correct position of the hood 2, you need to know the direction to the light source (for example, the Sun), which is determined by the corresponding sensors 4.

The direction sensors 4 to the light source can be installed at the edges of the hood 2 or on the outer surface of the telescope body 1.

Blend 2 is a three-dimensional part in the form of a plate bent in one direction with a constant radius of curvature corresponding to the radius of the input aperture of the telescope. The plate has beveled upper corners, and can be made in the form of a half cylinder with beveled upper corners. As a special case, the sweep of the plate on a plane is a parabolic figure bounded by two conjugate edges - the upper and lower.

Blend 2 (Fig. 4) has two lateral end parts 5 (angles adjacent to the lower end of the plate) and upper part 6 (the central part of the upper edge of the plate). Thus, the lower edge of the hood 2 (the end face of the plate) (installed in the plane of the input aperture) is formed by two lateral end parts 5, and is perpendicular to the optical axis of the telescope. From the two lateral end parts 5 to the center, the height of the lens hood naturally increases, reaching its maximum (h ₀ ) at the highest point (O) of part 6. Thus, lens hood 2 has a maximum height h ₀ (in a direction parallel to the axis of the optical telescope) whose value satisfies the relation:

h ₀ = D / tan α, [cm]

where D is the diameter of the circumference of the input aperture of the telescope, [cm];

α is the minimum angular distance between the directions to the observed object and an external source of illumination, degrees (°).

The bottom end of the plate has a length (L) equal to half the circumference with an allowable deviation of not more than 5% (L = πD / 2 ± 5%).

The projection of the upper point (O) onto the diameter D is located in the middle of the lower end of the plate — point A in FIG. four.

A curved plate in a flat scan has a bevel line h (ϕ), (Fig. 5) which lies in a region whose lower boundary is determined by the expression h ₁ (ϕ), and the upper boundary by the expression h ₂ (ϕ), where:

h ₁ (ϕ) = h ₀ ⋅cos ϕ, [cm],

h ₂ (ϕ) = h ₀ ⋅cos ^1/2 ϕ, [cm],

-90 ° <ϕ <90 °

h ₁ (ϕ) ≤h (ϕ) ≤h ₂ (ϕ) is the height at the corresponding point of the plate,

ϕ is the angle between the radius (segment OA) drawn to the center point of the lower end and the radius (segment OV) drawn to the point relative to which the value h (ϕ) is determined, which characterizes the height of the plate at this point, degrees (see Fig. 4 )

Thus, a variant is possible when a curved plate in a flat scan has a bevel line described by the equation h (ϕ) = h ₀ ⋅cos ϕ (see implementation example).

Comparing the shadow areas from the hood in the plane of the input aperture when using the semi-cylindrical hood of the prototype telescope (Fig. 3) and the inventive hood (Fig. 4), it is seen that both hoods provide the same minimum distance from the edge of the aperture to the border of the shadow, while the shadow is from the semi-cylindrical The famous blend is excessively large. Shadows are shown in gray, the dotted circle is the input aperture, the oblique dotted lines are the rays from the light source, passing near the edge of the hood 2.

In FIG. 5 shows the sweep of the prototype-telescope lens hood (dashed line) and the inventive lens hood (the boundary lines corresponding to the expressions h ₁ (ϕ) and h ₂ (ϕ) are shown by solid and dash-dot lines). Comparing the sweep, we can conclude that with an equal maximum height, the area and, accordingly, the mass of the inventive hood is less (see Fig. 5).

An optical telescope with a hood works as follows. In the mode of measurements in outer space, the optical axis of the telescope will be directed to the center of the observed object, remote from the nearest edge of the illumination source (Sun) by an angle α. In accordance with the signal from the direction sensors 4 to the light source (Sun) installed on the edges of the hood 2 or on the outer surface of the telescope body 1, a command is automatically issued to drive 3 to rotate the hood 2 around the optical axis of the telescope in the corresponding direction until it reaches the position when blend 2 with its outer surface turns toward the sun (light source). Thus, the sun's rays will not fall on the entrance aperture of the telescope. The optical system builds an image of the observed object at the radiation receiver. Radiation from the source of illumination does not reach the input aperture, and, consequently, does not reach the optical system of the telescope and the receiver.

A specific example of a blend.

Initial data:

The optical telescope has an input aperture diameter of D-100 cm;

minimum angular distance between directions to the observed object and a third-party illumination source α-60 °.

In this way:

The lower end of the hood (plate) L = πD / 2 = 157 cm ± 5%;

height (h ₀ ) at the upper point of the upper part (6) of the hood (maximum height):

h ₀ = D / tg α = 157 / tg60 ° = 90.6 cm;

We get the pattern of increasing the height of the hood in accordance with the formula:

h ₁ (ϕ) = h ₀ ⋅cos ϕ = 90.6 cos ϕ

at - 90 ° <ϕ <90 °

Further, counting around the axis of the hood various values of the angle ϕ, we obtain:

, тогда высота края в этой точке h_1/1=90,6⋅cos 30°=78,4 см;

then the height of the edge at this point is h _1/1 = 90.6⋅cos 30 ° = 78.4 cm;

, тогда высота края в этой точке h_1/2=90,6⋅cos 60°=45,3 см;

then the height of the edge at this point is h _1/2 = 90.6⋅cos 60 ° = 45.3 cm;

, тогда высота края в этой точке h_1/3=90,6⋅cos 90°=0 см.

then the height of the edge at this point is h _1/3 = 90.6⋅cos 90 ° = 0 cm.

Based on this, a scan of the hood was built — see FIG. 5, a solid line (the dotted line for visualization shows a scan of the upper boundary of the bevel of the hood in accordance with the equation h ₂ (ϕ) = h ₀ ⋅cos ^1/2 ϕ) level) of protecting the entrance aperture of the optical telescope from exposure to a bright astronomical source located at a small angular distance from the observed weak astronomical object.

Claims (16)

1. A hood designed to protect the optical telescope from interfering with illumination of third-party radiation sources, configured to be mounted on a circular input aperture of an optical telescope, which is a three-dimensional part in the form of a plate bent in one direction with a constant radius of curvature corresponding to the radius of the entrance aperture of the telescope, and having an upper edge with beveled corners, while the length of the lower end of the plate is equal to half the circumference of the input aperture with an acceptable deviation not olee 5%, and the maximum height of the plate (h ₀₎ given by the relation: h ₀ = D / tg α, where D is the diameter of the input aperture of the optical telescope; α is the minimum angular distance between the directions to the observed object and a third-party source of illumination. 2. The hood according to claim 1, characterized in that the plate is made in the form of a half cylinder with beveled upper corners. 3. The hood according to claim 1, characterized in that the curved plate in a flat scan has a bevel line h (ϕ) lying in a region whose lower boundary is determined by the expression h ₁ (ϕ) and the upper boundary by the expression h ₂ (ϕ) where: h ₁ (ϕ) = h ₀ ⋅cos ϕ, h ₂ (ϕ) = h ₀ ⋅cos ^1/2 ϕ, -90 ° <ϕ <90 ° h ₁ (ϕ) ≤h (ϕ) ≤h ₂ (ϕ) is the height at the corresponding point of the plate, ϕ is the angle between the radius drawn to the center point of the lower end and the radius drawn to the point relative to which the value of h (ϕ) is determined, which characterizes the height of the plate at this point. 4. The hood according to claim 1, characterized in that the curved plate in a flat scan has a bevel line described by the equation h (ϕ) = h ₀ ⋅cos ϕ, -90 ° <ϕ <90 ° where h (ϕ) is the height at the corresponding point of the plate, ϕ is the angle between the radius drawn to the center point of the lower end and the radius drawn to the point relative to which the value of h (ϕ) is determined, which characterizes the height of the plate at this point.

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