JPH03271710A - Focal position moving device - Google Patents

Abstract

PURPOSE:To obtain a satisfactory image in which no aberration is generated by attaching a driving for moving a primary mirror or a secondary mirror, and an actuator for varying a mirror shape to one of the primary mirror or the secondary mirror, to the moving device. CONSTITUTION:The driving device 6b, etc., for moving the primary mirror 1 or the secondary mirror 6a, and the actuator 5, etc., for varying a mirror surface shape to one of the primary mirror 1 or the secondary mirror 6a, to the moving device. An electromagnetic wave coming from a top board is reflected by the primary mirror 1, thereafter, reflected again by the secondary mirror 6a, passes through a Cassegrain- type hole 3 and forms an image by a first Cassegrain-type focus 11, and subsequently, at the time of moving a focal position to a second Cassegrain-type focus 12, etc., the secondary mirror 6a is driven by a secondary mirror driving mechanism 6b, and a distance between the primary mirror and the secondary mirror 6a is varied. In the case the distance between the primary mirror 1 and the secondary mirror 6a is varied, etc., an aberration is generated, but force is applied to the primary mirror 1 by the actuator 5 and it is deformed, and formed in such a shape as offsetting the aberration. In such a manner, even if the focal position in moved, a satisfactory image can be obtained without generating a large aberration.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a reflection imaging system in a reflection telescope, etc.
In particular, it relates to something that moves the focal point position.

[Conventional technology]

FIG. 6 is a schematic sectional view showing a conventional focal position moving device. In the figure, l is a flexible primary mirror having, for example, a paraboloid or hyperboloid shape, 2 is a mirror cell attached to a pedestal, and 3 is a A Cassegrain hole is formed in the center of the primary mirror 1 and the mirror cell 2, 4 is a support device that supports the primary mirror 1 from the mirror cell 2, 16 is a removable first secondary mirror having a hyperboloid shape, and 7 is a support device for supporting the primary mirror 1 from the mirror cell 2; A cylindrical top tube that supports the first secondary mirror 16; 8 a spider that hangs the top tube 7 in a cross; 9 a ring-shaped top tube that supports the first secondary mirror 16 via the top tube 7 and the spider 8; 10 is a truss connecting mirror center 2 and top ring 9; 11 is a first Cassegrain focal point on which electromagnetic waves such as light or infrared rays coming from a celestial body are focused; 17 is a second secondary mirror 17 having a different shape from the first secondary mirror 16;
This is a replacement secondary mirror set that combines spacer 17b and spacer 17b, and spacer 17b is the first secondary mirror set. It plays the role of compensating for the difference between the setting position and 16. Further, reference numeral 12 denotes a second Cassegrain focus when the replacement secondary mirror set 17 is attached in place of the first secondary mirror 16.

Next, the effect will be explained. tvL waves such as light and infrared rays coming from celestial bodies are first reflected by the primary mirror 1, and then reflected by the first secondary mirror 1.
6, passes through the Cassegrain hole 3, and forms an image at the first Cassegrain focal point 11.

The shapes of the primary mirror 1 and the second secondary mirror 16 are determined so that the aberration at the first Cassegrain focus 11 is minimized in this configuration.

Next, the first Cassegrain focus is changed to the second Cassegrain focus 1.
To move to 2, move to 1st as indicated by the dotted line in the figure.
The secondary mirror 16 is replaced with a replacement secondary mirror 17. Here, the spacer 17b functions to extend the focal length. Generally, when the secondary mirror is brought closer to the primary mirror, the focal point moves away from the primary mirror, and the amount of movement is about the square of the m ratio multiplied by the amount of movement of the secondary mirror. In a normal reflecting telescope, the m ratio is 5 to 1.
0, the movement of the secondary mirror is transmitted to the focal point magnified by 20 to 100 times, and even when the focal point is moved several tens of centimeters, the movement of the secondary mirror only needs to be about several tens of millimeters.

Also, the second vice! 17a has a shape that cancels out aberrations caused by moving its position,
It also plays a role in forming an image with small aberrations at the focal point after movement.

[Problem to be solved by the invention]

The conventional focus position moving method is configured as described above, and although the amount of movement of the secondary mirror required to move the focal point is small, it is necessary to replace the secondary mirror, and There are problems in that it is necessary to prepare a plurality of secondary mirrors corresponding to different focal positions, and a mechanism for attaching and detaching the secondary mirrors is also required.

This invention was made to solve the above-mentioned problems, and it is possible to move the focal point without replacing the secondary mirror and obtain a good image without causing large aberrations at the focal point after the movement. The object of the present invention is to obtain a focal position moving device that can move the focus position.

[Means to solve the problem]

The focal position moving device according to the present invention includes a drive device that moves the primary mirror or the secondary mirror to change the distance between the primary mirror and the secondary mirror, and an actuator that changes the shape of the mirror surface on either the primary mirror or the secondary mirror. be.

(Function) In this invention, a driving device for moving the primary mirror or the secondary mirror and an actuator for changing the shape of the mirror surface are attached to either the primary mirror or the secondary mirror to adjust the distance between the primary mirror and the secondary mirror. By driving the mirror, the focal position is moved and the shape of the primary or secondary mirror is changed, so the focal position can be moved without replacing the secondary mirror, and large aberrations are avoided even at the focal point after movement. [Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing a focal position moving device according to an embodiment of the present invention, in which the same reference numerals as in FIG. 6 indicate the same or corresponding parts, and 5 is attached to the mirror cell 2 and the primary mirror 1; An actuator 6 deforms the supranuclear fil by applying force to the primary mirror 1, and a movable secondary mirror 6 is a combination of a secondary mirror 6a and a secondary mirror drive mechanism 6b.

Next, the operation will be explained. Electromagnetic waves coming from a celestial body are reflected by the primary mirror 1, then reflected again by the secondary mirror 6a, pass through the Cassegrain hole 3, and form an image at the first Cassegrain focal point 11.

Next, in order to move the focal point position to the second Cassegrain focal point 12, the secondary mirror 6a is driven by the secondary mirror drive mechanism 6b to change the distance between the primary mirror 1 and the secondary mirror 6a (in the figure, the distance between the primary mirror 1 and the secondary mirror 6a is changed).
(bring it closer to the primary mirror 1 side).

Normally, the shapes of the primary mirror 1 and the secondary mirror 6a are determined so that aberrations are minimized at the first Cassegrain focus 11, so aberrations occur when the distance between the primary mirror 1 and the secondary mirror 6a changes, etc. However, in the present invention, a sharp image cannot be formed at the second Cassegrain focal point 12, but in the present invention, the actuator 5 applies force to the primary mirror l to deform it to cancel out this aberration. A good image can also be obtained at the second Cassegrain focal point 12.

As described above, in this embodiment, the distance between the primary mirror 1 and the secondary mirror 6a is adjusted by the secondary mirror drive mechanism 6b that moves the secondary mirror 6a, and the primary mirror 1.
An actuator 5 that changes the shape of the mirror surface is attached to the holder, and the secondary mirror 6a is moved toward the primary mirror 1 to move the Cassegrain focal point and change the shape of the primary mirror 1. The focal point position can be moved without replacement, and a good image can be obtained without causing large aberrations even after the focal point has been moved.

In the above embodiment, the actuator 5 was provided separately from the primary mirror support device 4, but since the actuator 5 can perform the primary mirror support function, the actuator and the main mirror support device 4 can be connected as shown in FIG. It may also be used as a mirror support device. In this way, by reducing the number of parts, the device can be made lighter and less expensive.

Further, in the above embodiment, a mechanism was shown in which the secondary mirror drive mechanism was driven manually and mechanically, but as shown in FIG. 3, a remote control device may be attached and it may be driven electrically. . In this case, there is no need for humans to approach the secondary mirror (and the amount of work associated with moving the focal position is reduced).
and risks can be reduced.

Further, in the above embodiment, the primary mirror 1 is deformed to cancel the aberrations, but as a method for canceling the aberrations, as shown in FIG.
This may be done by modifying a.

In addition, in the above embodiment, a method was shown in which the primary mirror 1 is deformed so as to cancel out all the aberrations, but since most of the aberrations are third-order spherical aberrations, only the amount of deformation that cancels out the third-order spherical aberrations is necessary. It may be added to the primary mirror, the secondary mirror, or both, and the deterioration in imaging performance due to the aberration left to cancel is small. In this case, since only third-order spherical aberration with a low spatial frequency is canceled out, the number of actuators 5 can be reduced, and the device can be made lighter and cheaper. Furthermore, since the amount of deformation is small, it can also be applied to mirrors made of rigid materials.

Further, in the above embodiment, the case where a Cassegrain focus is moved to another Cassegrain focus has been described, but it may be used when a Cassegrain focus and a Nassmith focus are used together. To explain in detail using FIG. 5, 13 is a third mirror which is a plane mirror placed in the optical path, and 14 is a plane symmetrical to the first Cassegrain focus 11 with respect to the third mirror 13 when the third mirror 13 is inserted. The first Nasmyth focus 15 is the second Nasmyth focus after the first Nasmyth focus has been moved.

By the way, when the first Cassegrain focal point 11 is placed at a convenient position for lowering the frame, simply inserting the third mirror 13 does not necessarily bring the Nasmyth focal point to a convenient position for use.

For example, as shown in FIG.
is located inside the structure and may not be available. However, if the device is configured in the same manner as described in the above embodiment, the first mirror can be used without replacing the secondary mirror.
The second Nassmith focal point 14 can be moved to the second Nassmith focal point 15, which is convenient for use, and the same effects as in the embodiment described above can be achieved.

Further, in the above embodiment, the case where the focal position of the reflecting telescope is moved has been described, but the application of the present invention is not limited to this, and may be used, for example, in an antenna device or other reflecting imaging device. .

〔Effect of the invention〕

As described above, the focal position moving device according to the present invention includes a drive device that moves the primary mirror or the secondary mirror to change the distance between the primary mirror and the secondary mirror, and a mirror surface shape on either the primary mirror or the secondary mirror. By attaching a changing actuator and driving the secondary mirror or primary mirror, the focal position can be moved and the shape of the primary mirror or secondary mirror can be changed, so the focal point can be moved without replacing the secondary mirror itself. This reduces the amount of work required to shift the focal point, the risks associated with the work, and the work time, eliminates the need for equipment such as lanes required for replacement work, and eliminates the need to prepare multiple secondary mirrors. This has the effect of making the device cheaper.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing a focal position moving device in a reflecting telescope according to an embodiment of the present invention, and FIGS.
This figure is a schematic diagram showing a focal position moving device according to another embodiment of the present invention, and FIG. 6 is a schematic diagram showing a focal position shifting device in a conventional reflecting telescope. In the figure, 1 is a primary mirror, 4 is a mirror support device, 5 is an actuator, 6a is a secondary mirror, 6b is a secondary mirror drive device, 11 is a focal point before movement, and 12 is a focal point after movement. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) In a reflecting telescope that has a primary mirror and a secondary mirror, an actuator that is attached to at least one of the primary mirror or the secondary mirror and that deforms the mirror, and a drive device that moves the primary mirror or the secondary mirror in the optical axis direction. What is claimed is: 1. A focal position moving device comprising: changing the distance between the primary mirror and the secondary mirror, and deforming the primary mirror or the secondary mirror.