Long-focal-length wide-angle aurora imaging lens optical system

Abstract

The invention belongs to the technical field of optical systems, and particularly relates to a long-focal-length wide-angle aurora imaging lens optical system, which comprises a front lens group, a narrow-band filter and a rear lens group, and is characterized in that an afocal lens group with infinite focal length and a positive-focal-power lens group are combined by the system, and the focal power of the lens is reasonably distributed; the light incident angle and the imaging quality at the position of the optical filter are optimized in a targeted manner, so that the lens realizes long focal length on the premise of a large view field, and the spatial resolution and the image height of the imager are further improved.

Description

Technical Field

[0001] The present application belongs to the technical field of optical systems, and specifically relates to a long focal length wide angle aurora imaging lens optical system. Background Art

[0002] Aurora imagers are the main tools for observing auroras, and are mainly composed of imaging lenses and focal plane detectors. The spatial resolution of aurora imagers is proportional to the focal length of the lens. The longer the focal length of the lens, the greater the image height, and it can match larger detectors. The detection sensitivity of the imager is proportional to the square of the pixel size. Large-sized detectors generally have large pixel sizes and a large number of pixels. The pixel size can be further increased through pixel binning to improve sensitivity. The focal length of existing aurora imager lenses is generally less than 5mm, and the longest does not exceed 10mm. The short focal length of the lens will result in low spatial resolution and sensitivity of the aurora imager. The long-focal-length aurora imaging lens usually has a field of view of only 3° to 30°, which cannot achieve large-scale aurora observation.

[0003] The aurora has a large range and an extremely narrow spectrum, so the lens is required to have a large field of view and a narrowband filter is needed to accurately filter the aurora. If the incident angle of the light at the filter position in the lens is too large, the filter transmission spectrum will drift toward the short-wave direction, resulting in a decrease in the transmittance of the observed spectrum, which in turn leads to a decrease in the sensitivity of the imager. Existing wide-angle (or full-sky) aurora imaging lenses mainly use a standard industrial fisheye lens + collimating lens group + narrowband filter + imaging lens group design. This structure guarantees the collimation of the light at the filter position to a certain extent, but the lens aperture is limited by the standard industrial fisheye lens, which reduces the light flux entering the system, resulting in the inability to detect weak aurora signals. There are pupil matching errors when assembling various parts of the system, which affects the imaging quality. Summary of the invention

[0004] Based on the above problems, the present application designs a new optical system structure, combining an afocal lens group with infinite focal length and a positive focal power lens group, and placing the filter behind the afocal lens group to ensure the collimation of light at the filter position. The lens adopts an integrated design to avoid the limitations of standard industrial lenses on light throughput and the drawbacks of pupil matching errors. Its technical solution is:

[0005] A long focal length wide angle aurora imaging lens optical system comprises a front lens group, a narrow band filter and a rear lens group; the front lens group comprises a front positive lens group and a rear positive lens group, when light enters, the front positive lens group converges the light in the direction of the optical axis and is incident on the rear positive lens group, the rear positive lens group re-diverges the light and makes it become a parallel light beam again; the parallel light emitted by the rear positive lens group is incident on the narrow band filter at a small angle, and the light is finally focused on an imaging plane through the rear lens group to form a clear image.

[0006] Preferably, the front positive lens group includes a negative meniscus lens 1, a positive meniscus lens 1, a lens, a plano-convex positive lens 1 and a positive meniscus lens 2 placed in sequence; the side of the lens opposite to the positive meniscus lens 1 is an aperture.

[0007] Preferably, the rear positive lens group includes a third positive meniscus lens, a second plano-convex positive lens, a third plano-convex positive lens and a second negative meniscus lens, which are arranged in sequence.

[0008] Preferably, the narrow-band filter substrate is made of fused quartz material with high transmittance and low dispersion, and the curvature radii of the front and back surfaces are both ∞.

[0009] Preferably, the rear lens group includes a plano-convex positive lens four, a positive meniscus lens four and a negative meniscus lens three, which are arranged in sequence.

[0010] Preferably, the system debugging steps are as follows:

[0011] Step 1: Obtain the parameters of the focal wide-angle aurora imaging lens optical system, field of view angle γ, working band λ, aperture D, focal length f, maximum incident angle α of light at the filter position, back intercept L BFL , the total length of the system is L, and the initial optical path structure is built;

[0012] Step 2: Calculate the field of view, working band, aperture, focal length, maximum incident angle of light at the filter position, back intercept, and the absolute value of the difference between the total length of the system and the design requirements |Δγ|, |Δλ|, |ΔD|, |Δf|, |Δα|, |ΔL of the optical system. BFL | and |ΔL|;

[0013] Step 3: Set the field of view angle, working band, aperture, focal length, maximum incident angle of light at the filter position, back intercept, and the constraints of the total length of the system: γ', λ', D', f', α', L BFL ' and L', the absolute value of the difference between this constraint and the design requirement |Δγ'|, |Δλ'|, |ΔD'|, |Δf'|, |Δα'|, |ΔL BFL '| and |ΔL'| are less than the results calculated in step 2;

[0014] Step 4: Optimize system parameters and structure;

[0015] Step 5: Check the system MTF and spot diagram. When the system MTF is ≥ 0.7 and the spot diagram RMS radius is ≤ 5 μm,

[0016] If yes, proceed to step 6, otherwise return to step 4;

[0017] Step 6: Calculate the field of view, working band, aperture, focal length, maximum incident angle of light at the filter position, back intercept, and the absolute value of the difference between the total length of the system and the design requirements |Δγ|, |Δλ|, |ΔD|, |Δf|, |Δα|, |ΔL of the optical system BFL | and |ΔL|, if the absolute value of the difference is equal to 0, terminate, otherwise return to step 3.

[0018] Preferably, in order to ensure the collimation of light at the filter position, a front positive lens group and a rear positive lens group are combined to form an afocal system with an infinite focal length as the front lens group of the lens; assuming that the overall focal power of the optical system is The focal length of the front lens group is The focal power of the front positive lens group is The focal power of the rear positive lens group is The field of view of the optical system is γ, the maximum incident angle of the light at the narrowband filter position is α, the overall focal length of the system is f, and the back intercept is L BFL , then the constraints are as follows:

[0019] |α|≤7°;

[0020]

[0021] Preferably, by utilizing the front lens group and the rear lens group to cooperate with each other in the divergence and convergence of light, through reasonable optical power distribution and optimization, the wide-angle lens can achieve a relatively long focal length while maintaining certain optical performance, and the constraints are as follows:

[0022] Assume that the focal power of the rear lens group with positive focal power is The focal length is f3, the aperture is D3, and the overall aperture of the system is D:

[0023]

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention designs a new optical system structure, combines an afocal lens group with infinite focal length and a positive focal power lens group, reasonably distributes the lens focal length, and specifically optimizes the light incident angle and imaging quality at the filter position, so that the lens can achieve a long focal length under the premise of a large field of view, thereby improving the spatial resolution and image height of the imager. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the structural principle diagram of this application;

[0027] Figure 2 is the MTF curve of the long focal length wide angle aurora imaging lens optical system of the present invention;

[0028] Figure 3 It is a point diagram of the optical system of the long focal length wide angle aurora imaging lens of the present invention.

[0029] In the figure: 1-front lens group, 11-front positive lens group, 12-rear positive lens group;

[0030] 111-negative meniscus lens 1, 112-positive meniscus lens 1, 113-lens, 114-plano-convex positive lens 1, 115-positive meniscus lens 2;

[0031] 121-positive meniscus lens 3, 122-plano-convex positive lens 2, 123-plano-convex positive lens 3, 124-negative meniscus lens 2; 2-narrow band filter;

[0032] 3-rear lens group, 31-fourth plano-convex positive lens, 32-fourth positive meniscus lens, 33-threeth negative meniscus lens. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] To solve the problems that the existing wide-angle aurora imaging lens has a short focal length, resulting in low spatial resolution of the imager, inability to adapt to large-size detectors, and decreased sensitivity. The present invention designs a new optical system structure, combines an afocal lens group with an infinite focal length and a positive focal lens group, reasonably distributes the lens focal length, and specifically optimizes the incident angle of light and imaging quality at the filter position, so that the lens can achieve a long focal length under the premise of a large field of view, thereby improving the spatial resolution and image height of the imager. The lens includes a front lens group 1, a narrow-band filter 2, and a rear lens group 3 with positive focal length. When light enters the lens, the afocal front lens group 1 causes the light to focus first and then diverge. From the perspective of geometric optics, this effect of focusing first and then diverging is equivalent to increasing the propagation path length of the light, so that the light can converge at a relatively longer distance when it converges through the subsequent rear lens group 3. In order to ensure the collimation of light at the filter position, a front positive lens group 11 and a rear positive lens group 12 are combined into an afocal system with an infinite focal length as the front lens group 1 of the lens. When the infinitely far high-angle light enters the front lens group, the front positive lens group 11 converges the light toward the optical axis to form a real focus, and the beam diameter gradually decreases, which is conducive to reducing the size of the front lens group and reducing the processing cost. The light emitted from the rear focus of the front positive lens group 11 continues to propagate and is incident on the rear positive lens group 12. The rear positive lens will re-diverge these light rays, making them parallel beams again. Through targeted optimization and the distribution of the focal length of each lens, the parallel light emitted from the front lens group 1 is incident on the narrow-band filter 2 at a small angle, avoiding the phenomenon that the filter transmission spectrum drifts due to the large incident angle of the light, resulting in a decrease in the transmittance of the observation band. The edge light of the large field of view becomes a small field of view beam after passing through the front lens group 1. A simple three-piece structure is used as the rear lens group 3, so that the light can finally be focused on the imaging plane to form a clear image. The front lens group 1 and the rear lens group 3 cooperate with each other in the divergence and convergence of light. Through reasonable distribution and optimization of focal length, the wide-angle lens can achieve a relatively long focal length while maintaining certain optical performance. Long focal length lenses can not only improve the spatial resolution of imagers, but also have large image heights, which can be matched with large-size detectors to improve the sensitivity of imagers.

[0035] The present invention integrates the afocal front lens group 1, the narrow-band filter 2 and the rear lens group 3 into an integrated joint optimization design, avoiding the limitation of the light transmission amount and the pupil matching error between the parts in the standard industrial fisheye lens in the traditional wide-angle aurora lens structure. The debugging steps are as follows:

[0036] Step 1: Obtain the design parameters of the focal wide-angle aurora imaging lens optical system, including the field of view angle γ, working band λ, aperture D, focal length f, maximum incident angle α of the filter position, and back intercept L BFL , the total length of the system is L; build the initial optical path structure;

[0037] Step 2: Calculate the field of view, working band, aperture, focal length, maximum incident angle of light at the filter position, back intercept, and the absolute value of the difference between the total length of the system and the design requirements |Δγ|, |Δλ|, |ΔD|, |Δf|, |Δα|, |ΔL BFL | and |ΔL|;

[0038] Step 3: Set the field of view angle, working band, aperture, focal length, maximum incident angle of light at the filter position, back intercept, and the constraints of the total length of the system: γ', λ', D', f', α', L BFL ' and L', the absolute value of the difference between this constraint and the design requirement |Δγ'|, |Δλ'|, |ΔD'|, |Δf'|, |Δα'|, |ΔL BFL '| and |ΔL'| are less than the results calculated in step 3;

[0039] Step 4: Optimize system parameters and structure;

[0040] Step 5: Check the system MTF and spot diagram. When the system MTF is ≥ 0.7 (@ 60lp / mm) and the spot diagram RMS radius is ≤ 5μm, proceed to step 6, otherwise return to step 4;

[0041] Step 6: Calculate the field of view, working band, aperture, focal length, maximum incident angle of light at the filter position, back intercept, and the absolute value of the difference between the total length of the system and the design requirements |Δγ|, |Δλ|, |ΔD|, |Δf|, |Δα|, |ΔL of the optical system BFL | and |ΔL|, if the absolute value of the difference is equal to 0, terminate, otherwise return to step 3.

[0042] When light enters the lens, the afocal front lens group 1 causes the light to focus first and then diverge. From the perspective of geometric optics, this effect of focusing first and then diverging is equivalent to increasing the length of the light propagation path, so that when the light converges through the subsequent rear lens group 3, it can converge over a relatively longer distance. In order to ensure the collimation of light at the filter position, a front positive lens group 11 and a rear positive lens group 12 are combined to form an afocal system with an infinite focal length as the front lens group 1 of the lens. The overall optical power of the optical system is The focal length of the front lens group 1 is The optical power of the front positive lens group 11 is The focal length of the rear positive lens group 12 is The field of view of the optical system is γ, and the maximum incident angle of the light at the filter position is α. The overall focal length of the system is f, and the back intercept is L BFL .in:

[0043] |α|≤7°;

[0044]

[0045]

[0046] When the infinitely far high-angle light enters the front lens group, the front positive lens group 11 converges the light toward the optical axis to form a real focus, and the beam diameter gradually decreases, which is conducive to reducing the size of the front lens group and reducing the processing cost. The light emitted from the rear focus of the front positive lens group 11 continues to propagate and is incident on the rear positive lens group 12. The rear positive lens will re-diverge these light rays, making them parallel beams again. Through targeted optimization and the distribution of the focal length of each lens, the parallel light emitted from the front lens group 1 is incident on the narrow-band filter 2 at a small angle, avoiding the phenomenon that the filter transmission spectrum drifts due to the large incident angle of the light, resulting in a decrease in the transmittance of the observation band. The edge light of the large field of view becomes a small field of view beam after passing through the front lens group 1. A simple three-piece structure is used as the rear lens group 3, so that the light can finally be focused on the imaging plane to form a clear image. The front lens group 1 and the rear lens group 3 cooperate with each other in the divergence and convergence of light. Through reasonable distribution and optimization of focal length, the wide-angle lens can achieve a relatively long focal length while maintaining certain optical performance. The optical power of the positive optical power rear lens group 3 is The focal length is f3, the aperture is D3, and the overall aperture of the system is D:

[0047]

[0048] Long focal length lenses can not only improve the spatial resolution of imagers, but also have large image heights, which can be matched with large-size detectors to improve the sensitivity of imagers.

[0049] The optical path structure of the long focal length wide angle aurora imaging lens of the present invention is as follows Figure 1 , consisting of an afocal front lens group 1, a narrowband filter 2, and a positive focal power rear lens group 3. The front lens group is responsible for compressing the large-angle light at infinity, which is conducive to achieving large-field imaging. The combination of the front and rear lens groups is equivalent to performing two "operations" on the light. Compared with a single lens structure, it can make the convergence point of the light farther, thereby increasing the equivalent focal length and achieving a long focal length effect.

[0050] The optical system of the long focal length wide angle aurora imaging lens designed by the present invention has a field of view of 100°, a focal length of -22mm, a clear aperture of 8mm, an image plane diameter of 35.28mm, a working spectrum of 555-561nm, and an MTF ≥ 0.7 (@60lp / mm). It can be equipped with a narrowband filter with a central band of 557.7nm and a half-width at half maximum of 3nm. It can be adapted to large-size detectors with an imaging area greater than or equal to 35.28×35.28mm, and is used to observe the green (557.7nm) aurora produced by the excitation of oxygen atoms. When the detector pixel size is ≤10μm, a spatial resolution better than 50m (@100km orbit altitude) can be achieved. The rear intercept of the lens is greater than 120mm, which leaves enough space for the design of subsequent focusing mechanisms, beam splitters, reflectors and other structures. The lens structure is composed of the following: Figure 1 .

[0051] The detailed parameters and composition of each part of the optical system are as follows:

[0052] The focal length of the front lens group 1 is less than -5000mm, and it is composed of the front positive lens group 11 and the rear positive lens group 12. It is approximately an afocal system with a focal length of negative infinity. Its function is to collimate the large-angle light from the edge of the field of view into the narrow-band filter to avoid the light incident angle being too large, which causes the filter to drift through the spectrum and causes the transmittance of the observation band to decrease. The compression function of the front lens group 1 on the field of view angle is the key to the aurora imaging lens to achieve a large field of view + long focal length, so that the infinitely far off-axis light enters the rear optical system at a smaller angle, which is conducive to the correction of spherical aberration, astigmatism, etc.

[0053] The front positive lens group 11 is composed of five lenses. Among them, the negative meniscus lens 111 is a negative meniscus lens with a large focal length, and the front and rear curvature radii are 79.941 and 21.376mm respectively, and the thickness is 15.29mm. It has more functions of compressing the field of view, and the refractive index is 1.7552, and the Abbe number is 27.547; the positive meniscus lens 112, the front and rear curvature radii are -43.472 and -39.317mm respectively, the thickness is 23.945mm, the refractive index is 1.7469, and the Abbe number is 51.009; the lens 113 is a plano-convex positive lens, the front and rear curvature radii are ∞ and -89.379mm respectively, the thickness is 12.5730mm, and the refractive index is 1. 7555, with an Abbe number of 45.661; the front surface of lens 113 is the system aperture; a plano-convex positive lens 114, with front and rear curvature radii of 85.466 and ∞mm respectively, a thickness of 23.942mm, a refractive index of 1.6968, and an Abbe number of 56.2; a positive meniscus lens 115, with front and rear curvature radii of 39.45 and 38.067mm respectively, a thickness of 22.837mm, a refractive index of 1.7408, and an Abbe number of 27.762; the intervals between the five lenses 111, 112, 113, 114, and 115 are 36.853, 0.334, 25.432, and 20.479mm respectively.

[0054] The rear lens group 12 is composed of four lenses, and its focus coincides with the focus of the front positive lens group 11. The light emitted by the front positive lens group 11 will be refracted into a parallel light beam after passing through the rear positive lens group 12 and then emitted into the narrow-band filter 2. The positive meniscus lens 3 121 has a front and rear curvature radius of -66.854 and -53.415 mm respectively, a thickness of 22.234 mm, a refractive index of 1.946, and an Abbe number of 17.944; the plano-convex positive lens 2 122 has a front and rear curvature radius of ∞ and -270.34 mm respectively, a thickness of 24.678 mm, a refractive index of 1.5796, and an Abbe number of 53.866; the plano-convex positive lens 3 123 has a front and rear curvature radius of 221. 82 and ∞mm, thickness is 18.602mm, refractive index is 1.6074, Abbe number is 56.667; negative meniscus lens 124, front and back curvature radius are 202.73 and 129.327mm respectively, thickness is 12.89mm, refractive index is 1.946, Abbe number is 17.944; the intervals between the four lenses of positive lens group 121, 122, 123, 124 are 294.507, 43.94, 0.21mm respectively. The distance between 11 and 12 is 34.743mm.

[0055] The narrowband filter substrate uses fused quartz material with high transmittance, low dispersion, high hardness and low thermal expansion coefficient, with a refractive index of 1.4585, an Abbe number of 67.821, a front and back curvature radius of ∞, and a thickness of 10mm. The interval between the front lens group 1 and the front surface of the filter is 20.002mm.

[0056] The rear lens group 3 is a positive lens group, composed of a simple three-piece structure, responsible for re-converging the small-angle incident light emitted from the front lens group 1 to form a clear image. By appropriately increasing the focal length of the rear lens group 3 and reasonably adjusting the divergence of the light in the front lens group, the light can converge at a farther distance after two refractions, thereby achieving a long focal length. Plano-convex positive lens 31, front and rear curvature radii are 172.859 and ∞mm respectively, thickness is 15mm, refractive index is 1.5639, Abbe number is 60.791; positive meniscus lens 32, front and rear curvature radii are 95.766 and 253.649mm respectively, thickness is 22.604mm, refractive index is 1.6516, Abbe number is 58.416; negative meniscus lens 33, front and rear curvature radii are 337.793 and 101.195mm respectively, thickness is 18.76mm, refractive index is 1.9229, Abbe number is 18.895. The intervals between the three lenses 31, 32, and 33 are 0.21 and 14.694mm respectively. The interval between the rear surface of the filter and the rear lens group 3 is 20.002mm. The distance between the rear lens group 3 and the image plane 4 is 140.02 mm, and the long back focus leaves enough space for the design of subsequent focusing mechanisms, dichroic prisms, reflectors and other structures.

[0057] The front and rear lens groups are jointly optimized to distribute the optical power reasonably and uniformly for the target, avoiding the problem that the light throughput of traditional aurora imaging lenses is limited by the front-end standard industrial fisheye lens and the pupil matching error occurs when assembling the various parts of the system.

[0058] The specific structure of the optical system of the long focal length wide angle aurora imaging lens of the present invention is shown in the table below.

[0059]

[0060]

[0061] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A long focal length wide angle aurora imaging lens optical system, characterized in that: It includes a front lens group, a narrow-band filter and a rear lens group; the front lens group includes a front positive lens group and a rear positive lens group. When light enters, the front positive lens group converges the light in the direction of the optical axis and is incident on the rear positive lens group, and the rear positive lens group re-diverges the light to make it a parallel beam again. The parallel light emitted by the rear positive lens group enters the narrow-band filter at a small angle, and passes through the rear lens group so that the light can finally be focused on the imaging plane to form a clear image.

2. The long focal length wide angle aurora imaging lens optical system according to claim 1, characterized in that: The front positive lens group includes a negative meniscus lens 1, a positive meniscus lens 1, a lens, a plano-convex positive lens 1 and a positive meniscus lens 2 which are placed in sequence; the side of the lens opposite to the positive meniscus lens 1 is an aperture.

3. The long focal length wide angle aurora imaging lens optical system according to claim 1, characterized in that: The rear positive lens group includes a positive meniscus lens 3, a plano-convex positive lens 2, a plano-convex positive lens 3 and a negative meniscus lens 2 which are arranged in sequence.

4. The long focal length wide angle aurora imaging lens optical system according to claim 1, characterized in that: The narrow-band filter substrate is made of fused quartz material with high transmittance and low dispersion, and the curvature radii of the front and back surfaces are both ∞.

5. The long focal length wide angle aurora imaging lens optical system according to claim 1, characterized in that: The rear lens group includes a plano-convex positive lens four, a positive meniscus lens four and a negative meniscus lens three which are arranged in sequence.

6. The long focal length wide angle aurora imaging lens optical system according to claim 1, characterized in that: The system debugging steps are as follows: Step 1: Obtain the parameters of the focal wide-angle aurora imaging lens optical system, including the field of view angle γ, working band λ, aperture D, focal length f, maximum incident angle α of the filter position, and back intercept L. BFL , the total length of the system is L, and the initial optical path structure is built; Step 2: Calculate the field of view, working band, aperture, focal length, maximum incident angle of light at the filter position, back intercept, and the absolute value of the difference between the total length of the system and the design requirements |Δγ|, |Δλ|, |ΔD|, |Δf|, |Δα|, |ΔL of the optical system. BFL | and |ΔL|; Step 3: Set the field of view angle, working band, aperture, focal length, maximum incident angle of light at the filter position, back intercept, and the constraints of the total length of the system: γ', λ', D', f', α', L BFL ' and L', the absolute value of the difference between this constraint and the design requirement |Δγ'|, |Δλ'|, |ΔD'|, |Δf'|, |Δα'|, |ΔL BFL '| and |ΔL'| are less than the results calculated in step 2; Step 4: Optimize system parameters and structure; Step 5: Check the system MTF and spot diagram. When the system MTF is ≥ 0.7 and the spot diagram RMS radius is ≤ 5 μm, proceed to step 6, otherwise return to step 4; Step 6: Calculate the field of view, working band, aperture, focal length, maximum incident angle of light at the filter position, back intercept, and the absolute value of the difference between the total length of the system and the design requirements |Δγ|, |Δλ|, |ΔD|, |Δf|, |Δα|, |ΔL of the optical system BFL If the absolute value of the difference is equal to 0, the process terminates; otherwise, the process returns to step 3.

7. The long focal length wide angle aurora imaging lens optical system according to claim 6, characterized in that: The front positive lens group and the rear positive lens group are combined into an afocal system with an infinite focal length as the front lens group of the lens; Assume that the overall optical power of the optical system is The focal length of the front lens group is The focal power of the front positive lens group is The focal power of the rear positive lens group is The field of view of the optical system is γ, the maximum incident angle of the light at the narrowband filter position is α, the overall focal length of the system is f, and the back intercept is L BFL , then the constraints are as follows: |α|≤7°； 8. The long focal length wide angle aurora imaging lens optical system according to claim 6, characterized in that: By utilizing the cooperation of the front lens group and the rear lens group in the divergence and convergence of light, and through reasonable distribution and optimization of optical power, the wide-angle lens can achieve a relatively long focal length while maintaining certain optical performance. The constraints are as follows: Assume that the focal power of the rear lens group with positive focal power is The focal length is f3, the aperture is D3, and the overall aperture of the system is D:

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