Dual-band common-aperture astronomical telescope combining main focus and clamped focus

Abstract

The invention relates to an optical astronomical telescope, in particular to a dual-band common-aperture astronomical telescope combining a main focus and a clamped focus, and aims to solve the problem that an existing optical astronomical telescope does not have the daytime observation capability. The system comprises a main optical system lens group composed of a Schmidt correction mirror and a Mangin reflector, a visible light post-correction lens group composed of a third lens, a fourth lens and a fifth lens, a near-infrared post-correction lens group composed of a sixth lens, a seventh lens and an eighth lens, a first detector and a second detector. The system can work in a visible light wave band mode and a near-infrared wave band mode at the same time, and is good in imaging quality and high in stability. The light path of the visible light band mode is from the Schmidt correction mirror to the Mangin reflector to the third lens to the fourth lens to the fifth lens, and the light path of the near-infrared band mode is from the Schmidt correction mirror to the Mangin reflector to the third lens to the sixth lens to the seventh lens to the eighth lens.

Description

TECHNICAL FIELD

[0001] The present application relates to an optical astronomical telescope, in particular to a dual-band co-aperture astronomical telescope combining main focus and focal length. BACKGROUND

[0002] The optical astronomical telescope is an important tool for observing space targets, which can search, detect, locate and continuously track celestial bodies and artificial space targets, and has broad application prospects in the fields of astronomy and space target monitoring.

[0003] At present, the optical astronomical telescope mainly uses the visible light band for astronomical observation, but it can only observe at night and does not have the ability to observe during the day, mainly because there is a high sky background in the visible light band during the day, and the dark space target is submerged in the sky background. SUMMARY

[0004] The purpose of the present application is to solve the problem that the existing optical astronomical telescope does not have the ability to observe during the day, and to provide a dual-band co-aperture astronomical telescope combining main focus and focal length.

[0005] To achieve the above-mentioned purpose, the technical solution provided by the present application is:

[0006] A dual-band co-aperture astronomical telescope combining main focus and focal length, characterized in that:

[0007] It comprises a main optical system lens group composed of a Schmidt corrector and a Mangin reflector, a visible light rear correction lens group composed of a third lens, a fourth lens and a fifth lens, a near-infrared rear correction lens group composed of a sixth lens, a seventh lens and an eighth lens, and a first detector and a second detector.

[0008] The Schmidt corrector and the Mangin reflector are arranged in sequence along the direction of propagation of the incident light; the third lens, the fourth lens, the fifth lens and the first detector are arranged in sequence on the side of the Schmidt corrector away from the Mangin reflector; the Mangin reflector is a hollow mirror, the sixth lens, the seventh lens, the eighth lens and the second detector are arranged in sequence on the side of the Schmidt corrector close to the Mangin reflector, and the seventh lens is coaxially arranged in the hollow structure of the Mangin reflector;

[0009] The image plane of the first detector is defined as the first image side, and the image plane of the second detector is defined as the second image side; the surface of each optical lens close to the first detector is defined as the first surface, and the surface close to the second detector is defined as the second surface.

[0010] The Schmidt corrector is a positive focal power convex surface moon lens facing the first image side;

[0011] The Mangin mirror is a positive-power optical lens with a convex surface facing the second image side;

[0012] The third lens is a positive-power meniscus lens with a convex surface facing the second image side;

[0013] The fourth lens is a positive-power lenticular lens;

[0014] The fifth lens is a positive-power meniscus lens with a convex surface facing the first image side;

[0015] The sixth lens is a negative-power meniscus lens with a convex surface facing the second image side;

[0016] The seventh lens is a negative-power meniscus lens with a convex surface facing the second image side;

[0017] The eighth lens is a positive-power meniscus lens with a convex surface facing the second image side;

[0018] The first surface of the Schmidt corrector, the second surface of the Mangin mirror, the first surface of the third lens, the first and second surfaces of the fourth lens, the second surface of the fifth lens, the second surface of the sixth lens, the first and second surfaces of the seventh lens, and the first and second surfaces of the eighth lens are all spherical surfaces; the second surface of the Schmidt corrector, the first surface of the Mangin mirror, and the first surface of the sixth lens are all high-order aspherical surfaces; the second surface of the third lens and the first surface of the fifth lens are both quadratic surfaces; wherein a spectral light-splitting film is coated on the second surface of the third lens, for transmitting visible light reflected by the Mangin mirror and reflecting near-infrared light reflected by the Mangin mirror.

[0019] Further, the first surface of the Mangin mirror is a refractive surface, and the second surface is a reflective surface.

[0020] Further, the radius of curvature of the first surface of the Schmidt corrector is 667.76 mm, and the radius of curvature of the second surface of the Schmidt corrector is -37639 mm;

[0021] The radius of curvature of the first surface of the Mangin mirror is -405.21 mm, and the radius of curvature of the second surface of the Mangin mirror is -809.26 mm;

[0022] The radius of curvature of the first surface of the third lens is -1592.20 mm, and the radius of curvature of the second surface of the third lens is -369.73 mm;

[0023] The radius of curvature of the first surface of the fourth lens is 115.65 mm, and the radius of curvature of the second surface of the fourth lens is -593.87 mm;

[0024] The radius of curvature of the first surface of the fifth lens is 291.16mm, and the radius of curvature of the second surface of the fifth lens is 117.77mm;

[0025] The radius of curvature of the first surface of the sixth lens is -79.89mm, and the radius of curvature of the second surface of the sixth lens is -406.81mm;

[0026] The radius of curvature of the first surface of the seventh lens is -61.21mm, and the radius of curvature of the second surface of the seventh lens is -71.90mm;

[0027] The radius of curvature of the first surface of the eighth lens is -2341.36mm, and the radius of curvature of the second surface of the eighth lens is -109.41mm.

[0028] Further, the thickness of the Schmidt corrector lens is 35mm;

[0029] The thickness of the Mangin mirror is 25mm;

[0030] The thickness of the third lens is 23.5mm;

[0031] The thickness of the fourth lens is 25.6mm;

[0032] The thickness of the fifth lens is 18mm;

[0033] The thickness of the sixth lens is 20mm;

[0034] The thickness of the seventh lens is 20mm;

[0035] The thickness of the eighth lens is 20mm.

[0036] Further, the distance between the Schmidt corrector lens and the Mangin mirror is 233.9mm;

[0037] The distance between the Schmidt corrector lens and the third lens is 20mm;

[0038] The distance between the Schmidt corrector lens and the sixth lens is 156mm;

[0039] The distance between the third lens and the fourth lens is 51.7mm;

[0040] The distance between the fourth lens and the fifth lens is 0.35mm;

[0041] The distance between the sixth lens and the seventh lens is 79mm;

[0042] The distance between the seventh lens and the eighth lens is 69mm.

[0043] Further, the aspherical coefficients K1, A1, B1, C1 of the second surface of the Schmidt corrector are respectively:

[0044] K1 = 2.7 x 10 3 , A1 = -9.64 x 10 -10 , B1 = -6.23 x 10 -15 , C1 = 6.77 x 10 -21 ;

[0045] The aspherical coefficients K2, A2, B2, C2 of the first surface of the Mangin mirror are respectively:

[0046] K2 = 0.66, A2 = 3.5 x 10 -10 , B2 = 4.5 x 10 -16 , C2 = 7.1 x 10 -20 ;

[0047] The aspherical coefficient K3 of the second surface of the third lens is -4.8;

[0048] The aspherical coefficient K5 of the first surface of the fifth lens is 38;

[0049] The aspherical coefficients A6, B6, C6 of the first surface of the sixth lens are respectively:

[0050] A6 = 5.68 x 10 -8 , B6 = 1.39 x 10 -10 , C6 = -7.59 x 10 -14 .

[0051] Further, the materials of the Schmidt corrector and the Mangin mirror are both JGS-1;

[0052] The material of the third lens is H-LaK67;

[0053] The materials of the fourth lens and the eighth lens are both H-QK3L;

[0054] The material of the fifth lens is H-ZF39;

[0055] The material of the sixth lens is H-K3;

[0056] The material of the seventh lens is H-LaK59.

[0057] Further, the resolution of the first detector is 4096 x 4096, and the pixel size is 9 μm x 9 μm;

[0058] The resolution of the second detector is 1280 x 1024, and the pixel size is 15 μm x 15 μm.

[0059] Compared with the prior art, the application has the beneficial effects that:

[0060] 1. The main focus and focus combined dual-band common-aperture astronomical telescope provided by the application can work in a visible light band mode and a near-infrared band mode through the spectrum splitting film plated on the second surface of the third lens, the light path of the visible light band mode is: Schmidt corrector mirror -> Mangin reflector -> third lens -> fourth lens -> fifth lens, and the light path of the near-infrared band mode is: Schmidt corrector mirror -> Mangin reflector -> third lens -> sixth lens -> seventh lens -> eighth lens; the near-infrared band mode with a larger F number is used for observation in the daytime, and the visible light band mode with a large relative aperture and a large field of view is used for observation at night, so that the requirements of astronomical observation in the daytime and at night are met, and the application range is wide.

[0061] 2. The main focus and focus combined dual-band common-aperture astronomical telescope provided by the application has a field of view of 5.2°*5.2°, a focal length of 400 mm, an entrance pupil diameter of 350 mm, and an F number of 1.14 in the visible light band mode, is suitable for a visible light camera with high resolution and a large target surface, and meets the requirements of a large field of view and a large aperture; the focal length is 2100 mm, the entrance pupil diameter is 350 mm, and the F number is 6 in the near-infrared band mode, the larger F number effectively suppresses the sky background, is suitable for a near-infrared camera with a resolution of 1280*1024 and a pixel size of 15*15, and meets the requirements of background suppression and a field of view for daytime observation.

[0062] 3. The main focus and focus combined dual-band common-aperture astronomical telescope provided by the application has a one-time imaging structure in two working modes, has a short axial size, small distortion, good imaging quality, high energy concentration, simple structure and high stability. BRIEF DESCRIPTION OF DRAWINGS

[0063] Figure 1 FIG. 1 is a structural schematic diagram of a main focus and focus combined dual-band common-aperture astronomical telescope embodiment of the application;

[0064] Figure 2 FIG. 2 is an optical path diagram of the main focus and focus combined dual-band common-aperture astronomical telescope embodiment of the application in a visible light band mode;

[0065] Figure 3 FIG. 3 is an MTF curve of the main focus and focus combined dual-band common-aperture astronomical telescope embodiment of the application in the visible light band mode at a spatial frequency of 56 lp / mm;

[0066] Figure 4 FIG. 4 is an encircled energy curve diagram of the main focus and focus combined dual-band common-aperture astronomical telescope embodiment of the application in the visible light band mode.

[0067] Figure 5 Distortion curve diagram of the main focus and the card focus combined dual-band common-aperture astronomical telescope embodiment in the visible light band mode;

[0068] Figure 6 Optical path diagram of the main focus and the card focus combined dual-band common-aperture astronomical telescope embodiment in the near-infrared band mode;

[0069] Figure 7 MTF curve of the main focus and the card focus combined dual-band common-aperture astronomical telescope embodiment in the near-infrared band mode at a spatial frequency of 33 lp / mm;

[0070] Figure 8 Enclosing circle energy curve diagram of the main focus and the card focus combined dual-band common-aperture astronomical telescope embodiment in the near-infrared band mode;

[0071] Figure 9 Distortion curve diagram of the main focus and the card focus combined dual-band common-aperture astronomical telescope embodiment in the near-infrared band mode;

[0072] BRIEF DESCRIPTION OF DRAWINGS

[0073] 1-Schmidt corrector, 2-Mangin reflector, 3-third lens, 4-fourth lens, 5-fifth lens, 6-sixth lens, 7-seventh lens, 8-eighth lens. DETAILED DESCRIPTION

[0074] The application will be further described below in conjunction with the drawings and specific embodiments.

[0075] A main focus and card focus combined dual-band common-aperture astronomical telescope, referring to Figure 1 , comprising a main optical system lens group composed of a Schmidt corrector 1 and a Mangin reflector 2, a visible light rear correction lens group composed of a third lens 3, a fourth lens 4 and a fifth lens 5, a near-infrared rear correction lens group composed of a sixth lens 6, a seventh lens 7 and an eighth lens 8, and a first detector and a second detector; the Schmidt corrector 1 and the Mangin reflector 2 are arranged in the order of the incident light propagation direction; the third lens 3, the fourth lens 4, the fifth lens 5 and the first detector are arranged in the order on the side of the Schmidt corrector 1 away from the Mangin reflector 2; the sixth lens 6, the seventh lens 7, the eighth lens 8 and the second detector are arranged in the order on the side of the Schmidt corrector 1 close to the Mangin reflector 2; the Mangin reflector 2 is a hollow mirror and is arranged at the periphery of the seventh lens 7; the image plane of the first detector is defined as a first image side surface, and the image plane of the second detector is defined as a second image side surface; the surface of each optical lens close to the first detector is defined as a first surface, and the surface close to the second detector is defined as a second surface;

[0076] The parameters of each lens are as follows:

[0077] The Schmidt corrector 1 is a positive focal power, convex surface facing the first image side meniscus lens; the first surface thereof is a spherical surface with a radius of curvature of 667.76 mm; the second surface thereof is a high-order aspherical surface with aspherical coefficients K1, A1, B1, C1 being K1 = 2.7 x 10 3 , A1 = -9.64 x 10 -10 , B1 = -6.23 x 10 -15 , C1 = 6.77 x 10 -21 , and a radius of curvature of -37639 mm; the thickness thereof is 35 mm; and the material thereof is JGS-1.

[0078] The Mangin mirror 2 is a positive focal power, convex surface facing the second image side optical lens, the first surface thereof is a high-order aspherical surface with aspherical coefficients K2, A2, B2, C2 being K2 = 0.66, A2 = 3.5 x 10 -10 , B2 = 4.5 x 10 -16 , C2 = 7.1 x 10 -20 , and a radius of curvature of -405.21 mm; the second surface thereof is a spherical surface with a radius of curvature of -809.26 mm; the thickness thereof is 25 mm; and the material thereof is JGS-1. The Mangin mirror 2 was invented by French officer Alphonse Mangin in 1876, and is a kind of refractive-reflective hybrid mirror. Its structure is that the back surface of the concave (second surface) mirror is coated with a reflective film, the incident light is first refracted into the glass through the first surface, is reflected by the reflective film on the back surface of the second surface, and is then refracted out of the glass by the first surface. Its core advantage is that the chromatic aberration and spherical aberration can be corrected at the same time by using the dispersion characteristics of the refractive material.

[0079] The third lens 3 is a positive focal power, convex surface facing the second image side meniscus lens, the second surface thereof is a quadratic surface with an aspherical coefficient K3 = -4.8 and a radius of curvature of -369.73 mm; a spectral light splitting film is coated on the second surface of the third lens 3, which is used for transmitting the visible light band of the light reflected by the second surface of the Mangin mirror 2 to the third lens 3, and reflecting the near-infrared band of the light reflected by the second surface of the Mangin mirror 2 to the sixth lens 6; the first surface thereof is a spherical surface with a radius of curvature of -1592.20 mm; the thickness thereof is 23.5 mm; and the material thereof is H-LaK67.

[0080] The fourth lens 4 is a positive focal power double convex lens, the first surface and the second surface thereof are both spherical surfaces, the radius of curvature of the second surface is -593.87 mm, and the radius of curvature of the first surface is 115.65 mm; the thickness thereof is 25.6 mm; and the material thereof is H-QK3L.

[0081] The fifth lens 5 is a convex meniscus lens with positive refractive power, convex surface facing the first image side, the second surface is a spherical surface with a radius of curvature of 117.77 mm, the first surface is a quadratic surface with a non-spherical coefficient K5 = 38, and the radius of curvature is 291.16 mm; the thickness is 18 mm; and the material is H-ZF39.

[0082] The sixth lens 6 is a convex meniscus lens with negative refractive power, convex surface facing the second image side, the first surface is a high-order aspherical surface, and the non-spherical coefficients A6, B6, and C6 are A6 = 5.68 x 10 -8 , B6 = 1.39 x 10 -10 , C6 = -7.59 x 10 -14 -79.89 mm; the second surface is a spherical surface with a radius of curvature of -406.81 mm; the thickness is 20 mm; and the material is H-K3.

[0083] The seventh lens 7 is a convex meniscus lens with negative refractive power, convex surface facing the second image side, the first surface and the second surface are both spherical surfaces, the radius of curvature of the first surface is -61.21 mm, and the radius of curvature of the second surface is -71.90 mm; the thickness is 20 mm; and the material is H-LaK59.

[0084] The eighth lens 8 is a convex meniscus lens with positive refractive power, convex surface facing the second image side; the first surface and the second surface are both spherical surfaces, the radius of curvature of the first surface is -2341.36 mm, and the radius of curvature of the second surface is -109.41 mm; the thickness is 20 mm; and the material is H-QK3L.

[0085] The distance between the Schmidt corrector lens 1 and the Mangin mirror 2 is 233.9 mm; the distance between the Schmidt corrector lens 1 and the third lens 3 is 20 mm; the distance between the Schmidt corrector lens 1 and the sixth lens 6 is 156 mm; the distance between the third lens 3 and the fourth lens 4 is 51.7 mm; the distance between the fourth lens 4 and the fifth lens 5 is 0.35 mm; the distance between the sixth lens 6 and the seventh lens 7 is 79 mm; and the distance between the seventh lens 7 and the eighth lens 8 is 69 mm. The resolution of the first detector is 4096 x 4096, and the pixel size is 9 μm x 9 μm; the resolution of the second detector is 1280 x 1024, and the pixel size is 15 μm x 15 μm.

[0086] The embodiment can work in visible light band mode and near-infrared band mode at the same time, referring to Figure 2 , the light path of the visible light band mode: Schmidt corrector lens 1 → Mangin mirror 2 → third lens 3 (visible light band light passes through the third lens 3) → fourth lens 4 → fifth lens 5; referring to Figure 6The optical path for the near-infrared mode is as follows: Schmidt corrector 1 → Mankin reflector 2 → third lens 3 (near-infrared light is reflected by the spectral beam splitter coating on the second surface of third lens 3) → sixth lens 6 → seventh lens 7 → eighth lens 8. During daytime, the near-infrared mode with its higher F-number is used for observations, while at night, the visible light mode with its large relative aperture and wide field of view is used for observations, accommodating both daytime and nighttime astronomical observations. The optical lenses shared by the visible and near-infrared modes are Schmidt corrector 1, Mankin reflector 2, and third lens 3.

[0087] The third lens 3 and the fourth lens 4 in the visible light post-correction lens group are used to correct the spherical aberration and chromatic aberration of the main optical system lens group, and the fifth lens 5 is used to converge the light again onto the target surface of the first detector. At the same time, the visible light post-correction lens group is a magnification lens group with a magnification of less than 1, and the focal length reaches the preset value through optical focal length matching. The field of view of the visible light band mode is 5.2°×5.2°, the focal length is 400mm, the entrance pupil diameter is 350mm, and the F number is 1.14. It is suitable for high-resolution, large-target visible light cameras, and meets the requirements of large field of view and large aperture. Figures 3-5 As shown in the figure, the MTF of the visible light band mode is better than 0.5 at a spatial frequency of 56lp / mm, 92% of the energy of the enclosing circle is concentrated in 2×2 pixels, and the distortion is less than 0.4%. It has good imaging quality and meets the requirements for space target observation.

[0088] Since the daytime skylight background in the near-infrared band is more than an order of magnitude lower than that in the visible light band, the near-infrared band can be used for daytime astronomical observations. The sixth lens 6, the seventh lens 7, and the eighth lens 8 in the near-infrared post-correction lens group are used to extend the focal length of the entire optical system and correct the spherical aberration and chromatic aberration of the main optical system lens group. Figures 7-9 As shown in the figure, the MTF of the near-infrared band mode is better than 0.4 at a spatial frequency of 33lp / mm, 88% of the energy of the enclosing circle is concentrated in 3×3 pixels, and the distortion is less than 0.4%. It has good imaging quality and meets the requirements for space target observation.

[0089] The capability of optical astronomical telescope to search and find targets at night depends on the field of view of the optical system, and the detection capability of space targets depends on the aperture D of the optical system. In the case of a certain size of the detector target surface, the larger the field of view, the smaller the focal length f, and the small focal length optical system needs a large aperture D (relative aperture = D / f) to meet the detection capability. The requirement of large field of view and large relative aperture greatly increases the difficulty of design and implementation of the optical system. The detection capability of space targets in the daytime depends on the suppression capability of the sky background. The energy of the sky background reaching the target surface is inversely proportional to the square of the relative aperture, and the relative aperture is the inverse of the F number, so a small relative aperture is beneficial to the observation of space targets in the daytime. The parameters of the optical astronomical telescope are designed in the present application, so that a large relative aperture (small F number) is obtained in the visible light band mode, and a small relative aperture (large F number) is obtained in the near-infrared band mode, and the observation requirements in both cases are considered.

Claims

1. A dual-band common aperture astronomical telescope combining prime focus and locking focus, characterized by: The invention comprises a main optical system lens group consisting of a Schmidt correction mirror (1) and a Mankin reflector (2), a visible light post-correction lens group consisting of a third lens (3), a fourth lens (4) and a fifth lens (5), a near-infrared post-correction lens group consisting of a sixth lens (6), a seventh lens (7) and an eighth lens (8), and a first detector and a second detector; The Schmidt correction mirror (1) and the Mankin reflector (2) are sequentially arranged along the propagation direction of the incident light; the third lens (3), the fourth lens (4), the fifth lens (5) and the first detector are sequentially arranged on a side of the Schmidt correction mirror (1) away from the Mankin reflector (2); the Mankin reflector (2) is a hollow mirror, the sixth lens (6), the seventh lens (7), the eighth lens (8) and the second detector are sequentially arranged on a side of the Schmidt correction mirror (1) close to the Mankin reflector (2), and the seventh lens (7) is coaxially arranged in the hollow structure of the Mankin reflector (2); The image plane of the first detector is defined as the first image side surface, and the image plane of the second detector is defined as the second image side surface; the surface of each optical lens close to the first detector is defined as the first surface, and the surface close to the second detector is defined as the second surface; The Schmidt correction lens (1) is a meniscus lens with positive optical power and a convex surface facing the first image side. The Mankin reflector (2) is an optical lens with positive optical power and a convex surface facing the second image side; The third lens (3) is a meniscus lens with positive optical power and a convex surface facing the second image side; The fourth lens (4) is a biconvex lens with positive optical power; The fifth lens (5) is a meniscus lens with positive optical power and a convex surface facing the first image side surface; The sixth lens (6) is a meniscus lens with negative optical power and a convex surface facing the second image side surface; The seventh lens (7) is a meniscus lens with negative optical power and a convex surface facing the second image side; The eighth lens (8) is a meniscus lens with positive optical power and a convex surface facing the second image side surface; The first surface of the Schmidt correction mirror (1), the second surface of the Mankin reflector (2), the first surface of the third lens (3), the first surface and the second surface of the fourth lens (4), the second surface of the fifth lens (5), the second surface of the sixth lens (6), the first surface and the second surface of the seventh lens (7), and the first surface and the second surface of the eighth lens (8) are all spherical surfaces; the second surface of the Schmidt correction mirror (1), the first surface of the Mankin reflector (2), and the first surface of the sixth lens (6) are all high-order aspherical surfaces; the second surface of the third lens (3) and the first surface of the fifth lens (5) are all quadratic surfaces; wherein a spectral spectroscopic film is coated on the second surface of the third lens (3) for transmitting light in the visible light band reflected by the Mankin reflector (2) and reflecting light in the near-infrared band reflected by the Mankin reflector (2).

2. The dual-band common aperture astronomical telescope combining prime focus and locking focus according to claim 1, characterized in that: The first surface of the Mankin reflector (2) is a refractive surface, and the second surface is a reflective surface.

3. The dual-band common aperture astronomical telescope combining prime focus and locking focus according to claim 2, characterized in that: The curvature radius of the first surface of the Schmidt correction mirror (1) is 667.76 mm, and the curvature radius of the second surface of the Schmidt correction mirror (1) is -37639 mm; The curvature radius of the first surface of the Mankin reflector (2) is -405.21 mm, and the curvature radius of the second surface of the Mankin reflector (2) is -809.26 mm; The curvature radius of the first surface of the third lens (3) is -1592.20 mm, and the curvature radius of the second surface of the third lens (3) is -369.73 mm; The curvature radius of the first surface of the fourth lens (4) is 115.65 mm, and the curvature radius of the second surface of the fourth lens (4) is -593.87 mm; The curvature radius of the first surface of the fifth lens (5) is 291.16 mm, and the curvature radius of the second surface of the fifth lens (5) is 117.77 mm; The curvature radius of the first surface of the sixth lens (6) is -79.89 mm, and the curvature radius of the second surface of the sixth lens (6) is -406.81 mm; The curvature radius of the first surface of the seventh lens (7) is -61.21 mm, and the curvature radius of the second surface of the seventh lens (7) is -71.90 mm; The curvature radius of the first surface of the eighth lens (8) is -2341.36 mm, and the curvature radius of the second surface of the eighth lens (8) is -109.41 mm.

4. The dual-band common aperture astronomical telescope combining prime focus and locking focus according to claim 3, characterized in that: The thickness of the Schmidt correction mirror (1) is 35 mm; The thickness of the Mankin reflector (2) is 25 mm; The thickness of the third lens (3) is 23.5 mm; The thickness of the fourth lens (4) is 25.6 mm; The thickness of the fifth lens (5) is 18 mm; The thickness of the sixth lens (6) is 20 mm; The thickness of the seventh lens (7) is 20 mm; The thickness of the eighth lens (8) is 20 mm.

5. The dual-band common aperture astronomical telescope combining prime focus and locking focus according to claim 4, characterized in that: The distance between the Schmidt correction mirror (1) and the Mankin reflector (2) is 233.9 mm; The distance between the Schmidt correction lens (1) and the third lens (3) is 20 mm; The distance between the Schmidt correction lens (1) and the sixth lens (6) is 156 mm; The distance between the third lens (3) and the fourth lens (4) is 51.7 mm; The distance between the fourth lens (4) and the fifth lens (5) is 0.35 mm; The distance between the sixth lens (6) and the seventh lens (7) is 79 mm; The distance between the seventh lens (7) and the eighth lens (8) is 69 mm.

6. The dual-band common aperture astronomical telescope combining prime focus and locking focus according to claim 5, characterized in that: The aspheric coefficients K1, A1, B1 and C1 of the second surface of the Schmidt correction mirror (1) are respectively: K1=2.7×10 3 ,A1=-9.64×10 -10 ,B1=-6.23×10 -15 ,C1=6.77×10 -21 ; The aspheric coefficients K2, A2, B2, and C2 of the first surface of the Mankin reflector (2) are respectively: K2=0.66,A2=3.5×10 -10 ,B2=4.5×10 -16 ,C2=7.1×10 -20 ; The aspheric coefficient of the second surface of the third lens (3) is K3=-4.8; The aspheric coefficient of the first surface of the fifth lens (5) is K5=38; The aspheric coefficients A6, B6, and C6 of the first surface of the sixth lens (6) are respectively: A6=5.68×10 -8 ,B6=1.39×10 -10 ,C6=-7.59×10 -14 。 7. The dual-band common aperture astronomical telescope combining prime focus and locking focus according to claim 6, characterized in that: The material of the Schmidt correction mirror (1) and the Mankin reflector (2) are both JGS-1; The material of the third lens (3) is H-LaK67; The fourth lens (4) and the eighth lens (8) are both made of H-QK3L; The material of the fifth lens (5) is H-ZF39; The sixth lens (6) is made of H-K3 material; The material of the seventh lens (7) is H-LaK59.

8. The dual-band common aperture astronomical telescope combining prime focus and locking focus according to claim 7, characterized in that: The resolution of the first detector is 4096×4096, and the pixel size is 9μm×9μm; The second detector has a resolution of 1280×1024 and a pixel size of 15 μm×15 μm.

Images