JP5511443B2 - telescope - Google Patents

Description

  The present invention relates to a telescope suitable for observing an astronomical object or a distant object with the naked eye.

As a telescope for observing a distant object with the naked eye based on an optical principle, a reflection type, a refraction type, or a catadioptric type telescope based on a reflection type is known.
The reflecting telescope has a simple configuration and is used for astronomical observation as a device that can be supplied at a relatively low cost. However, it is said that the conventional reflecting telescope is relatively difficult to align the optical axis.

On the other hand, although a refracting telescope is expensive, it is frequently used because it is unnecessary or easy to adjust the optical axis.
By the way, with an astronomical telescope that observes stars floating in space in detail, it is more convenient to have a mirror with a higher magnification, but as the magnification increases, the amount of light that can reach the focal point decreases, so it becomes darker. It is the fate of the optical telescope that a bright and clear image cannot be obtained.

  Therefore, in the case of the reflection type, a large reflecting mirror is used so that a larger amount of light can be taken in as the enlargement ratio is increased, and in the case of the refraction type, a lens having a large aperture is used.

  When a lens is used to refract light, the refractive index differs depending on the wavelength, so the focal position of each wavelength differs, and a phenomenon called so-called chromatic aberration occurs, and a clear image cannot be obtained. On the other hand, when using a reflector, such chromatic aberration does not occur, but if a reflector with a large aperture is used, a phenomenon called so-called coma aberration occurs from the periphery, and a clear image cannot be obtained. It is known that this coma can be reduced by using a reflector having a large F value. However, if a reflector having a large aperture and a large F value is to be used, the telescope inevitably increases in size, resulting in a dilemma that increases the difficulty in terms of money and operability. In the refraction method, it is of course preferable to combine a plurality of lenses to reduce chromatic aberration, and as a result, it is preferable to use a lens whose aberration is as close to zero as possible. However, it is extremely difficult to manufacture such a lens with a large aperture. The fact is that the amount of money has increased and has become expensive. Therefore, a reflective telescope that can use a large-diameter reflecting mirror at a relatively low cost has been used.

  Various reflection mirrors have been developed that reflect the reflected light from the primary mirror in the direction of the optical axis to form a focal point outside the primary mirror. For example, a parabolic concave mirror is used as the primary mirror, a hyperbolic convex mirror is used as the secondary mirror, and a Cassegrain-type reflective mirror with the focal point positioned outside the lens barrel, and a parabolic concave mirror is used as the primary mirror. In addition to the Gregory method using an elliptic concave mirror, various methods such as the Ritchie-Cretian method and the Doll-Carcam method have been proposed.

  Since these reflecting telescopes require secondary mirrors that are difficult to manufacture, such as hyperbolic convex mirrors and elliptic concave mirrors, it is actually difficult to manufacture high-precision telescopes. Also, with these reflecting telescopes, it is difficult to adjust the optical axis to match the optical axes of the observation units called primary mirror, secondary mirror, and eyepiece, and it is difficult to observe under optimal conditions. It is a fact.

  Therefore, in order to avoid the difficulty in manufacturing the various secondary mirrors used in these methods, a plane reflecting mirror is used as the secondary mirror, and it is bent in a direction perpendicular to the optical axis of the primary mirror and the telescope barrel Newton telescopes have been developed that can be observed outside the dome. The Newton telescope has been widely used as a widespread apparatus because it is easy to manufacture and can be manufactured at low cost.

However, the Newtonian reflecting telescope is unusable when used as a general telescope other than the astronomical telescope because the object is identified as an inverted image.
In addition, the Newtonian reflecting telescope, which is said to be the most popular and popular type of reflecting telescope, reflects the reflected light from the primary mirror in the vertical direction from the optical axis of the primary mirror and is called an eyepiece. Although an image is observed with an instrument, it is a drawback that it is difficult to adjust all of the primary mirror, secondary mirror, and eyepiece to the optimum positions.

  Furthermore, in the Newtonian reflecting telescope, when a large primary mirror is used, the position of the secondary mirror inevitably becomes the tip of the lens barrel, and the position of the eyepiece arranged at right angles therefrom is also the same as that of the lens barrel. It will be placed at the tip, and when observing stars at high latitudes, it will inevitably require a platform or stepladder for observation at high places, which is not only inconvenient but also dangerous. is there.

  Furthermore, when a plurality of telescopes are used and used separately, the focal positions of the individual telescopes are different, so that eyepieces that match each other are required. If the eyepiece can be made common, not only can the user spend unnecessary expenses, but all observations can be made with a familiar eyepiece, which is very convenient.

  In view of the above circumstances, the present invention does not require a secondary mirror that is difficult to manufacture with high accuracy, can be easily adjusted at a low cost, and can be manufactured at a low cost. An object of the present invention is to provide a telescope that is easy to use even when used as a telescope or an astronomical telescope.

In order to achieve the above object, a telescope according to the present invention comprises:
A parabolic mirror is used as a primary mirror, a plane mirror is arranged as a secondary mirror in front of the primary mirror on the optical axis, and the primary mirror reflected by the secondary mirror between the primary mirror and the secondary mirror is further disposed. By disposing a concave lens on the side of the secondary mirror with respect to the reflection focal position A of the reflected light from the mirror, light taken into the primary mirror from the outside passes through the primary mirror and the secondary mirror and the secondary mirror Is incident on the concave lens, and the light incident on the concave lens is emitted as parallel light into the lens holding tube and guided to the eyepiece.

Further, the present invention, it is preferable that the primary mirror F value of the parabolic mirror is used as (a ratio of the effective diameter of the focal distance and the primary mirror) is the range of 2-10.
Further, according to the present invention, it is preferable that a parabolic mirror used as the primary mirror has a through-hole having a diameter equal to or smaller than that of the plane mirror used as the secondary mirror in the center.

Furthermore, in the present invention, the shape of a plane mirror is used as the secondary mirror is circular, it is preferable that the diameter of 10% to 50% of the range of the diameter of the primary mirror.

In the present invention, it is preferable that the concave lens disposed between the primary mirror and the secondary mirror is an achromatic lens that does not cause chromatic aberration .

Furthermore, in the present invention, the F value of the concave lens disposed between said primary mirror and said secondary mirror coincides with the F value of the main mirror, is that the diameter of the range of 10mm~100mm preferable.

In the present invention, a planar reflecting plate may be provided on a parallel optical path emitted from the concave lens disposed between the primary mirror and the secondary mirror, and the reflected light may be introduced to an arbitrary place.
For example, in the case of a large reflecting telescope, when observing high-latitude stars, if the telescope is adjusted to that angle, the outer position of the primary mirror will be extremely low. When observing, it is necessary to observe at a high position. Therefore, when the eyepiece is arranged in that direction by bending the reflected light in an arbitrary angle direction using a single plane reflecting mirror, observation becomes extremely easy.

  Furthermore, for example, by using a total of three plane reflecting mirrors, the position of the eyepiece can be arranged at the center of gravity of the lens barrel. In this case, even if the lens barrel is tilted in an arbitrary latitude direction, it is possible to always observe at the same position, and it is possible to provide a large reflective telescope that is extremely easy to use.

  According to the telescope having such a configuration, a secondary mirror that is difficult to manufacture with high accuracy is unnecessary, and even if the telescope is tilted at an arbitrary angle, observation can be performed at the same position, and the center of gravity position of the lens barrel can be determined. Since the holding position of the lens barrel can be matched, there is no need for a heavy balancer to reduce the weight imbalance in order to bring the holding position closer to the eyepiece position as in the conventional device. The rotating and moving mechanism can be simplified and reduced in weight, which is very convenient.

  According to the telescope according to the present invention, a secondary mirror made of a hyperboloid which is difficult to manufacture is unnecessary, and the optical axis can be easily adjusted and manufactured at low cost. In addition, since it can be identified as an erect image, it can be used as a general telescope, and it can be used conveniently in an astronomical telescope.

FIG. 1 is a schematic view of a telescope according to an embodiment of the present invention. FIG. 2 is a schematic view of a telescope according to another embodiment of the present invention. FIG. 3 is a schematic view of a telescope according to still another embodiment of the present invention.

Hereinafter, a telescope according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing a telescope 10 according to an embodiment of the present invention, and particularly shows an example applied to an astronomical telescope.

In this telescope 10, a primary mirror 4 is disposed in one end of a barrel 2 formed in a substantially cylindrical shape, and a secondary mirror 6 is disposed in front of the optical axis of the primary mirror 4.
The primary mirror 2 is a parabolic concave mirror, and a through hole 4a is formed at the center thereof. The diameter of the through hole 4a of the primary mirror 4 is set to be equal to or less than or equal to the diameter of the secondary mirror 6. In addition, the F value (ratio between the focal length and the effective diameter of the primary mirror) of the primary mirror 4 is in the range of 3-6.

On the other hand, the secondary mirror 6 employs a plane reflecting mirror, and its outer shape is circular.
The diameter of the secondary mirror 6 is preferably in the range of 5% to 50% of the diameter of the primary mirror 4 and particularly preferably 15% to 30%.

  If the diameter of the secondary mirror 6 is made too large, the shadow of the same diameter will cover the primary mirror 4 and the efficiency will deteriorate. If the diameter is made too small, the shadow on the primary mirror 4 by the secondary mirror 6 will become small. However, since the space into which the concave lens 8 can be inserted is limited, it becomes unrealistic.

  If the diameter of the secondary mirror 6 is set in such a range, it becomes possible to safely insert the concave lens 8 that can minimize the influence of the shadow on the primary mirror 4 and obtain a highly accurate reflected light beam. Therefore, it is preferable.

A concave lens 8 disposed between the primary mirror 4 and the secondary mirror 6 is fixed to the tip of the lens holding cylinder 12. The F value of the concave lens 8 is the same as the F value of the primary mirror 4.
The concave lens 8 is preferably a high quality achromatic lens (apochromatic lens).

  The concave lens 8 disposed between the primary mirror 4 and the secondary mirror 6 has a conical shape with the focal position G of the reflected light from the primary mirror 4 as a vertex and the through hole 4a provided in the primary mirror 4 as a bottom surface. It has a size that fits within the area.

If the concave lens 8 is formed in such a size, high-precision observation is possible without blocking the optical path of the reflected light.
For example, light from a star or the like enters the lens barrel 2 as indicated by an arrow from the left side, that is, the side of the secondary mirror 6 in the figure, and is first reflected by the primary mirror 4 and arranged in front of the optical axis of the primary mirror 4. The light is further reflected by the secondary mirror 6 and travels directly toward the opposite focal point A on the side of the primary mirror 4, and passes through the concave lens 8 on the way to the opposite focal point A, where it is converted into parallel light, and the lens holding cylinder 12. Go inside. Then, the light travels through the lens holding tube 12 with the parallel light, and proceeds to the eyepiece (eyepiece) 16 side as it is. The light is collected by the eyepiece 16 when it exits the lens barrel 2, and is finally used for observation with a human eyeglass.

In the present embodiment, since light is emitted from the lens barrel 2 as parallel light, various eyepieces 16 corresponding to the parallel light can be used as they are.
On the other hand, when the observation in the posture of FIG. 1 is inconvenient, that is, the observation of looking at the light incident direction is inconvenient, as shown in FIG. It is also possible to arrange the plane reflecting mirror 20 and bend the optical path in an appropriate direction, and place the eyepiece 16 in an easily observable place for observation. In this case, the same eyepiece 16 can be used even when observed in the posture of FIG. 1 or the posture of FIG.

FIG. 3 is a schematic view showing still another embodiment of the telescope according to the present invention.
In this embodiment, the planar reflecting mirror 20 </ b> A is disposed between the concave lens 8 accommodated in the lens barrel 2 and the main mirror 4 in a state of being fixed to the lens support cylinder 12. Further, the eyepiece 16 is arranged in the reflection direction, and the parallel light is collected on the eyepiece 16.

  With such a configuration, the position of the eyepiece 16 can be arranged at the center of gravity of the lens barrel 2. Thereby, for example, in the case of a large telescope or the like, since the support base is disposed at the center of gravity of the lens barrel 2, the eyepiece 16 can be disposed on the support base. Therefore, even if the lens barrel 2 is tilted in an arbitrary latitude direction, it is possible to observe far away from the eyepiece 16 that is always at the same position.

Although the embodiments of the present invention have been described above, according to the telescope according to the present invention, since the secondary mirror is a plane mirror, a secondary mirror that is difficult to manufacture with high accuracy is unnecessary.
Further, the optical axis can be easily adjusted and can be manufactured at low cost. Moreover, since it can be seen as an erect image, it is convenient to use as a general telescope or astronomical telescope.

  Further, the concave lens 8 of the above embodiment is concave on only one side, but may be a lens having concaves on both sides.

2 barrel 4 primary mirror 4a hole 6 secondary mirror 8 concave lens 10 telescope 12 lens holding barrel 16 eyepiece 20 plane reflecting mirror 20A plane reflecting mirror

Claims (7)

  A parabolic mirror is used as a primary mirror, a plane mirror is arranged as a secondary mirror in front of the primary mirror on the optical axis, and the primary mirror reflected by the secondary mirror between the primary mirror and the secondary mirror is further disposed. By disposing a concave lens on the side of the secondary mirror with respect to the reflection focal position A of the reflected light from the mirror, light taken into the primary mirror from the outside passes through the primary mirror and the secondary mirror and the secondary mirror The telescope which is incident on the concave lens from above, and further, the light incident on the concave lens is emitted as parallel light into the lens holding tube and guided to the eyepiece. Telescope according to claim 1, wherein the F value of the parabolic mirror is used as the main mirror (the ratio of the effective diameter of the focal distance and the primary mirror) is the range of 2-10. The parabolic mirror used as the primary mirror is formed with a through-hole having a diameter equal to or less than the diameter of the flat mirror used as the secondary mirror at the center. The described telescope. Wherein the shape of the plane mirror is used as the secondary mirror is circular, according to claim 1, characterized in that the diameter of 10% to 50% of the range of the diameter of the main mirror telescope. The telescope according to any one of claims 1 to 4, wherein the concave lens disposed between the primary mirror and the secondary mirror is an achromatic lens that does not cause chromatic aberration. F values of the concave lens which is disposed between the secondary mirror and the primary mirror are consistent with F values of the primary mirror, according to claim 2, characterized in that the diameter of the range of 10mm~100mm telescope according to any one of to 5. Any of claims 1-6, characterized in that for introducing the flat reflecting plate is provided, the reflected light anywhere in the parallel light path emitted from the concave lens which is disposed between the primary mirror auxiliary mirror The telescope described in Crab.

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