Space solar spectropolarimeter based on built-in filter window assembly

Abstract

This invention belongs to the field of polarization measurement, and particularly relates to a space solar spectroscopic polarization telescope based on a built-in filter window assembly. It includes a telescope system, a relay system, and a spectrometer imaging system arranged sequentially along the optical path. The telescope system includes a primary mirror, a secondary mirror, and a built-in filter window assembly. The secondary mirror is located in the output optical path of the primary mirror, and the built-in filter window assembly is located in the output optical path of the secondary mirror. The built-in filter window assembly includes at least two filter glasses and a filter glass support. Each filter glass surface is coated with a filter film layer with different transmission bandwidths. This invention solves the weight, mechanical, and thermal control bottlenecks that restrict large-aperture space solar spectroscopic polarization telescopes by eliminating the front filter window and setting the built-in filter window assembly in the optical path, achieving a comprehensive improvement in optical performance, system reliability, and engineering feasibility.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polarization measurement, and particularly relates to a space solar spectrum polarization telescope based on a built-in filter window assembly. BACKGROUND

[0002] The sun, as the central celestial body of the solar system, is full of magnetized plasma from the convection zone to the whole atmosphere. The structure and evolution of the magnetic field directly dominate the morphology and core physical mechanism of solar activity. Most of the significant phenomena on the sun, such as sunspots, faculae, spicules, plages, coronal loops, filaments / prominences, coronal mass ejections (CMEs), flares, etc., are closely related to the magnetic field. The generation mechanism of the solar magnetic field, the heating principle of the million-degree coronal temperature, and the physical cause of solar eruption activity are also the core of the research of the magnetic field. Therefore, high-precision and high-resolution observation of the solar magnetic field is the key prerequisite for deepening solar scientific research and improving the accuracy of space weather forecasting.

[0003] At present, the international advanced solar magnetic field observation technology has entered the space stereoscopic detection stage, while the space solar magnetic field detection of China is still in its infancy. Although the Kuafu-1 satellite has been deployed for on-orbit operation, and subsequent plans such as Xinghe-2 and Kuafu-2 are planned, the stereoscopic observation of the solar magnetic field is gradually promoted, but the observation ability and accuracy of the existing equipment still cannot meet the needs of frontier scientific research and practical application, and it is urgent to develop higher-precision solar observation instruments to obtain more detailed solar magnetic field and spectral polarization data to provide solid support for related research and forecasting work.

[0004] One of the core approaches to improve the performance of solar observation instruments is to increase the effective aperture of the optical system. However, the traditional space solar spectrum polarization telescope generally adopts a front filter window design, which is composed of two optical glasses arranged in parallel at the front end of the optical system, and has the functions of band-pass filtering, blocking ultraviolet / infrared radiation, and preventing radiation. Since the front filter window is placed at the front end of the optical system and needs to cover the entire incident beam, its aperture must be larger than the clear aperture of the optical system. This leads to a significant technical contradiction: when trying to increase the aperture of the telescope to improve performance, the aperture and thickness of the filter window need to be increased simultaneously, and to ensure the surface accuracy of the two optical glasses, the weight of the support structure also needs to be increased accordingly. Engineering practice shows that when the aperture of the optical system increases by 50%, the weight of the front filter window and its support structure will increase by 300%, and the overall weight increases exponentially with the increase of the aperture. The high weight ratio of the front filter window leads to a serious imbalance in the weight distribution of the entire optical system, forming a layout of heavy head and light feet, which greatly worsens the mechanical response characteristics of the optical system and cannot meet the stringent environmental requirements of space detection.

[0005] The size and weight limitation caused by the front filter window directly leads to the difficulty in breaking through the optical aperture of the existing solar spectrum polarization telescope, thereby restricting the improvement of the detection accuracy, and failing to meet the urgent needs of China for high-precision observation of the solar magnetic field. Therefore, a new type of solar spectrum polarization telescope structure capable of breaking through this limitation is needed to promote China's space solar detection technology to the international advanced level. SUMMARY

[0006] Therefore, the present application aims to provide a space solar spectrum polarization telescope based on a built-in filter window assembly to solve the technical problem that the optical aperture of the existing solar spectrum polarization telescope is difficult to break through due to the use of a front filter window.

[0007] To achieve the above-mentioned purpose, the technical solution of the present application is as follows:

[0008] A space solar spectrum polarization telescope based on a built-in filter window assembly, comprising a telescope system, a relay system and a spectrometer imaging system arranged in sequence along the light path, characterized in that the telescope system comprises a primary mirror, a secondary mirror and a built-in filter window assembly, the secondary mirror is located in the exit light path of the primary mirror, and the built-in filter window assembly is located in the exit light path of the secondary mirror; the built-in filter window assembly comprises at least two filter glasses and a filter glass support, and a filter film layer with different transmission bandwidths is coated on the surface of each filter glass.

[0009] Further, the built-in filter window assembly comprises a first filter glass, a second filter glass, a first filter glass support and a second filter glass support, the first filter glass support is used for supporting the first filter glass, and the second filter glass support is used for supporting the second filter glass.

[0010] Further, the filter film layer coated on the surface of the first filter glass comprises a high reflection film and a narrow band pass film, the reflectivity of the high reflection film is greater than 99%, and the transmission bandwidth of the narrow band pass film is 5nm-10nm.

[0011] Further, the filter film layer coated on the surface of the second filter glass is an extremely narrow band pass film, and the transmission bandwidth of the extremely narrow band pass film is 3nm-5nm.

[0012] Further, the filter glass support adopts a flexible hinge structure and a flexible buffer pad, and the flexible buffer pad is arranged at the position where the flexible hinge structure contacts the filter glass.

[0013] Further, the telescope system further comprises a heat conduction assembly, the heat conduction assembly comprises a connecting piece and a connecting piece connected with each other, the connecting piece is connected with the filter glass support, the connecting piece is connected with the main frame body of the telescope, and the heat conduction coefficient of the connecting piece is less than that of the connecting piece.

[0014] Further, the relay system comprises, in sequence along the light path, a compensation lens group, a 1 / 4 wave plate, a polarization beam splitter, a reimaging lens group, and a scanning mechanism, the compensation lens group is used for aberration correction of the polarized light, the 1 / 4 wave plate is used for converting the linearly polarized light after aberration correction into circularly polarized light, the polarization beam splitter is used for splitting the circularly polarized light, the reimaging lens group is used for imaging the split circularly polarized light, and the scanning mechanism is used for spatial dimension scanning of the sunlight beam.

[0015] Further, the compensation lens group comprises a first lens to a fourth lens, and specific optical parameters are as follows:

[0016] The first lens has an optical aperture of 70mm, an Abbe number of 67.80, and a negative optical power;

[0017] The second lens has an optical aperture of 75mm, an Abbe number of 27.53, and a positive optical power;

[0018] The third lens has an optical aperture of 80mm, an Abbe number of 27.53, and a negative optical power;

[0019] The fourth lens has an optical aperture of 85mm, an Abbe number of 64.17, and a positive optical power;

[0020] The first lens and the second lens have a spacing of 6mm;

[0021] The second lens and the third lens have a spacing of 40mm;

[0022] The third lens and the fourth lens have a spacing of 1mm;

[0023] The polarization beam splitter has an extinction ratio of 5000:1;

[0024] The reimaging lens group comprises a fifth lens to an eighth lens, and specific optical parameters are as follows:

[0025] The fifth lens has an optical aperture of 80mm, an Abbe number of 64.17, and a negative optical power;

[0026] The sixth lens has an optical aperture of 82mm, an Abbe number of 27.60, and a positive optical power;

[0027] The seventh lens has an optical aperture of 80mm, an Abbe number of 27.60, and a negative optical power;

[0028] The eighth lens has an optical aperture of 100mm, an Abbe number of 64.17, and a positive optical power;

[0029] The fifth lens and the sixth lens have a spacing of 4mm;

[0030] The sixth lens and the seventh lens have a spacing of 22mm;

[0031] The interval between the seventh lens and the eighth lens is 40mm.

[0032] Further, the relay system further comprises a plane mirror arranged between the polarization beam splitter and the reimaging lens group, and the circularly polarized light after the beam splitting is reflected by the plane mirror and then incident on the reimaging lens group.

[0033] Further, the spectral imaging system comprises a slit, a spectrometer and a photodetector, and the light beam transmitted by the relay system is converged at the slit and then dispersed by the spectrometer and imaged on the photodetector.

[0034] Compared with the prior art, the application can achieve the following beneficial effects:

[0035] 1. By canceling the front filter window and arranging the built-in filter window assembly in the optical path, the size and weight of the front filter window are fundamentally solved, and the effective aperture of the optical system can be doubled under the same weight, thereby greatly improving the spatial resolution and spectral resolution of the space solar spectral polarization telescope, and laying a foundation for obtaining finer solar magnetic field and spectral data.

[0036] 2. By canceling the front filter window and arranging the built-in filter window assembly in the optical path, the unbalanced layout of the traditional design is eliminated, the weight distribution of the whole machine is more reasonable, and the mechanical response characteristics of the optical system are improved, so that the space exploration requirements of the harsh environment are met.

[0037] 3. The filter glass support adopts a thermal stress release flexible design, which can actively release stress when the temperature changes, ensure that the surface shape precision of the filter glass is stably within 1 lambda / 50 (rms), and ensure the extreme stability of the imaging quality of the space solar spectral polarization telescope in the on-orbit operation.

[0038] 4. Through the synergistic effect of the double film system of the two filter glasses, strict spectral selection and purification of sunlight are realized, more than 99% of the non-observation energy is rejected, the monochromaticity of the light entering the imaging system of the spectrometer is ensured, and pure light signals are provided for high-precision polarization measurement. BRIEF DESCRIPTION OF DRAWINGS

[0039] The accompanying drawings, which form a part of the present application, are used to provide further understanding of the present application, and the schematic embodiments of the present application and their descriptions are used to explain the present application, and do not constitute improper limitations on the present application. In the drawings:

[0040] Figure 1 The structure schematic view of the space solar spectral polarization telescope based on the built-in filter window assembly according to the embodiments of the present application is shown in the accompanying drawings.

[0041] Figure 2The structural schematic diagram of the built-in filter window assembly described in the embodiment of the present application.

[0042] Legend: telescope system 1, primary mirror 11, secondary mirror 12, built-in filter window assembly 13, first filter glass 131, second filter glass 132, first filter glass support 133, second filter glass support 134, heat conduction assembly 14, adapter 141, connecting piece 142, relay system 2, compensation mirror group 21, polarization beam splitter 22, reimaging mirror group 23, scanning mechanism 24, plane mirror 25, 1 / 4 wave plate 26, spectral imaging system 3, slit 31, spectrometer 32, photodetector 33. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and do not constitute a limitation on the present application.

[0044] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0045] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features limited by "first", "second" and the like can explicitly or implicitly include one or more features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0046] In the description of the present application, it should be noted that unless otherwise specified and limited, the terms "assembly", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0047] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0048] As Figure 1 shown, the embodiment of the present application provides a space solar spectrum polarization telescope based on a built-in filter window assembly, which comprises a telescope system 1, a relay system 2 and a spectrometer imaging system 3 arranged in sequence along the light path.

[0049] The telescope system 1 comprises a primary mirror 11, a secondary mirror 12 and a built-in filter window assembly 13, the secondary mirror 12 is located in the exit light path of the primary mirror 11, and the built-in filter window assembly 13 is located in the exit light path of the secondary mirror 12. The solar rays enter the telescope system 1 first reflected by the primary mirror 11 to the secondary mirror 12, and then reflected by the secondary mirror 12 into the built-in filter window assembly 13.

[0050] The built-in filter window assembly 13 comprises filter glass and filter glass supports, the number of filter glass and filter glass supports is the same and at least two, and the filter glass supports are used to support the filter glass. Different transmission bandwidth filter film layers are respectively coated on the surface of each filter glass to realize multiple screening of solar rays.

[0051] Taking two filter glasses as an example, the built-in filter window assembly 13 is described. As Figure 2 shown, the built-in filter window assembly 13 comprises a first filter glass 131, a second filter glass 132, a first filter glass support 133 and a second filter glass support 134.

[0052] The filter film layer coated on the surface of the first filter glass 131 comprises a high reflection film and a narrow band pass film, the reflectivity of the high reflection film is greater than 99%, about 99% of the light energy is reflected, and the transmission bandwidth of the narrow band pass film is 5nm-10nm, that is, the imaging light bandwidth transmitted by the first filter glass 131 is 5nm-10nm.

[0053] The filter film layer coated on the surface of the second filter glass 132 is an extremely narrow band pass film, and the transmission bandwidth of the extremely narrow band pass film is 3nm-5nm, that is, the imaging light bandwidth transmitted by the second filter glass 132 is 3nm-5nm.

[0054] Since the first filter glass 131 and the second filter glass 132 are directly irradiated by solar rays, the first filter glass support 133 and the second filter glass support 134 adopt a thermal stress release flexible design, which ensures that the surface shape accuracy of the filter glass is maintained at 1λ / 50 (rms) when the temperature changes.

[0055] The first filter glass support 133 and the second filter glass support 134 have the same structure. The first filter glass support 133 will be used as an example; the structure of the second filter glass support 134 can be understood similarly. The first filter glass support 133 adopts a flexible hinge structure commonly used in the aerospace field. This flexible hinge structure creates stress concentration and release areas by forming grooves or narrow necks of specific shapes on the support body. The flexible structure of the support body absorbs most of the stress caused by differences in thermal expansion through its own deformation. A flexible buffer pad made of a low-stiffness material (such as a flexible ceramic pad or elastic polymer) is provided at the contact point between the flexible hinge structure and the first filter glass 131. When the flexible hinge structure and the first filter glass 131 experience relative displacement due to thermal expansion and contraction, the flexible buffer pad deforms first, preventing the stress caused by hard contact from being directly transmitted to the first filter glass 131.

[0056] The telescope system 1 also includes the same number of heat-conducting components 14 as the filter glass support components. Each heat-conducting component 14 includes an adapter 141 and a connector 142. One end of the adapter 141 is connected to the filter glass support component, and the other end of the adapter 141 is connected to one end of the connector 142. The other end of the connector 142 is connected to the main frame of the telescope. The two ends of the connector 142 have different sizes. The end connected to the adapter 141 has a smaller size, and the end connected to the main frame of the telescope has a larger size, so that the connector 142 forms a gradient structure, so that the heat flux density per unit area does not suddenly spike at a certain interface.

[0057] The thermal conductivity of the adapter 141 is lower than that of the connector 142. The adapter 141 and the connector 142 have different thermal conductivity, which enables rapid heat transfer. The heat generated by the filter glass is first transferred to the filter glass support, then to the heat-conducting component 14, and finally to the main frame of the telescope. The main frame of the telescope is essentially a large heat sink.

[0058] The use of dual-filter glass in this invention is based on the following three considerations:

[0059] Firstly: graded filtering to achieve the extremely narrow band and high-purity spectrum required for solar observation.

[0060] Solar spectral polarization observations (such as the Hα band) require extremely high precision in the filter bandwidth. A single filter glass cannot simultaneously meet the needs of wide-range preliminary filtering and narrow-band fine screening. Therefore, this invention uses a double filter glass.

[0061] The first filter glass 131 performs the task of coarse filtering. It reflects more than 99% of non-target spectrum light (such as ultraviolet and infrared stray light) through a high-reflectivity film, allowing only a wide range of target spectrum light (5nm-10nm bandwidth) to pass through, which greatly reduces stray light interference from subsequent optical systems.

[0062] The second filter glass 132 then completes the fine screening task. It further compresses the light transmitted through the first filter glass 131 to an extremely narrow bandwidth (3nm-5nm), precisely matching the observation requirements of key spectral bands such as solar Hα, and ensuring the purity and accuracy of spectral polarization measurements.

[0063] The hierarchical collaboration of the dual-filter glass improves the control accuracy of the filter bandwidth by more than 2 times compared to the single-window scheme, effectively avoiding stray light interference with the observation of the fine structure of the solar magnetic field.

[0064] Secondly, it disperses the heat load, reducing the risk of heat accumulation and thermal deformation in a single window.

[0065] The power density of sunlight in the space environment is extremely high. If only a single-filter glass is used, it must simultaneously perform the dual tasks of reflecting all stray light and narrow-band filtering, which will lead to:

[0066] (1) The heat absorbed by the single-filter glass is too concentrated, and the thermal stress increases dramatically, which can easily cause deformation of the surface of the single-filter glass;

[0067] (2) The coating needs to meet the complex requirements of high reflectivity and ultra-narrow band at the same time, which is difficult to process and has a short life.

[0068] The dual-filter glass design can disperse the heat load. The first filter glass bears most of the heat reflected by stray light, while the second filter glass only handles the low-power light that has been initially filtered. The heat load of a single filter glass is reduced by more than 60%. With the heat-conducting component 14, the window surface accuracy can be stably maintained within 1λ / 50rms.

[0069] Thirdly: Improve system reliability and reduce the impact of single component failure.

[0070] Space equipment has stringent requirements for redundancy and reliability:

[0071] If a single-filter glass is used, damage to its coating or deformation of its surface will directly lead to the failure of the entire optical system.

[0072] The graded design of the dual-filter glass ensures that even if one filter glass experiences slight performance degradation, the other filter glass can still partially perform its filtering function, preventing the optical system from completely failing and improving the reliability of on-orbit operation.

[0073] The relay system 2 includes a compensation mirror group 21, a quarter-wave plate 26, a polarization beam splitter 22, a re-imaging mirror group 23, and a scanning mechanism 24 arranged sequentially along the optical path. The compensation mirror group 21 is used to correct aberrations in polarized light. The quarter-wave plate 26 is used to convert the aberration-corrected linearly polarized light into circularly polarized light. The polarization beam splitter 22 is used to split the circularly polarized light into beams. The extinction ratio of the polarization beam splitter 22 is 5000:1. The re-imaging mirror group 23 is used to image the split circularly polarized light. The scanning mechanism 24 is used to scan the spatial dimensions of the solar beam.

[0074] Both the polarization beam splitter 22 and the scanning mechanism 24 are existing technologies, so their specific structures will not be described in detail in this invention.

[0075] The compensating lens group 21 includes a first lens to a fourth lens, and the specific optical parameters of the first lens to the fourth lens are as follows:

[0076] The first lens has a light-transmitting aperture of 70mm, an Abbe number of 67.80, and a negative optical power.

[0077] The second lens has a light-transmitting aperture of 75mm, an Abbe number of 27.53, and a positive optical power.

[0078] The third lens has an aperture of 80mm, an Abbe number of 27.53, and a negative optical power.

[0079] The fourth lens has an aperture of 85mm, an Abbe number of 64.17, and a positive optical power.

[0080] The distance between the first lens and the second lens is 6mm;

[0081] The distance between the second lens and the third lens is 40mm;

[0082] The distance between the third lens and the fourth lens is 1 mm.

[0083] The re-imaging lens group 23 includes the fifth to eighth lenses, with the following specific optical parameters:

[0084] The fifth lens has an aperture of 80mm, an Abbe number of 64.17, and a negative optical power.

[0085] The sixth lens has an aperture of 82mm, an Abbe number of 27.60, and a positive optical power.

[0086] The seventh lens has an aperture of 80mm, an Abbe number of 27.60, and a negative optical power.

[0087] The eighth lens has a light-transmitting aperture of 100mm, an Abbe number of 64.17, and a positive optical power.

[0088] The distance between the fifth and sixth lenses is 4mm;

[0089] The distance between the sixth and seventh lenses is 22mm;

[0090] The distance between the seventh and eighth lenses is 40mm.

[0091] The relay system also includes a plane mirror 25 positioned between the polarization beam splitter 22 and the re-imaging mirror group 23. The circularly polarized light after beam splitting is reflected by the plane mirror 25 and incident on the re-imaging mirror group 23. The plane mirror 25 serves to deflect the light path and does not participate in imaging. The placement of the plane mirror 25 can reduce the axial length of the space solar spectral polarization telescope.

[0092] The spectral imaging system 3 includes a slit 31, a spectrometer 32, and a photodetector 33. The slit 31 is located at the focal plane of the re-imaging mirror group 23. The polarized light transmitted by the relay system 2 converges at the slit 31, and after being dispersed by the spectrometer 32, it is imaged onto the photodetector 33. During this process, the scanning mechanism 24 completes the spatial dimension scanning of sunlight, thereby obtaining a full solar magnetic map.

[0093] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0094] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A space-based solar spectral polarimetry telescope based on an in-situ filter window assembly, comprising a telescope system, a relay system and a spectrograph imaging system arranged in sequence along an optical path, characterized in that, The telescope system comprises a primary mirror, a secondary mirror and an internal filter window assembly, the secondary mirror is located in the outgoing light path of the primary mirror, and the internal filter window assembly is located in the outgoing light path of the secondary mirror; the internal filter window assembly comprises at least two filter glasses and filter glass supports, and filter film layers with different transmission bandwidths are respectively coated on the surfaces of the filter glasses; the telescope system further comprises a heat conduction assembly, the heat conduction assembly comprises a connecting piece and a connecting piece connected with each other, the connecting piece is connected with the filter glass support, the connecting piece is connected with the main frame body of the telescope, and the heat conduction coefficient of the connecting piece is smaller than that of the connecting piece.

2. The built-in filter window assembly based spatial solar spectrum polarimetric telescope according to claim 1, wherein, The internal filter window assembly comprises a first filter glass, a second filter glass, a first filter glass support and a second filter glass support, the first filter glass support is used for supporting the first filter glass, and the second filter glass support is used for supporting the second filter glass.

3. The built-in filter window assembly based spatial solar spectrum polarimetric telescope according to claim 2, characterized in that, The filter film layer coated on the surface of the first filter glass comprises a high-reflection film and a narrow-band pass film, the reflectivity of the high-reflection film is greater than 99%, and the transmission bandwidth of the narrow-band pass film is 5nm-10nm.

4. The built-in filter window assembly based spatial solar spectrum polarimetry telescope according to claim 2, characterized in that, The filter film layer coated on the surface of the second filter glass is an extremely narrow-band pass film, and the transmission bandwidth of the extremely narrow-band pass film is 3nm-5nm.

5. The built-in filter window assembly based spatial solar spectrum polarimetric telescope according to claim 1, wherein, The filter glass support adopts a flexible hinge structure and a flexible buffer pad, and the flexible buffer pad is arranged at the position where the flexible hinge structure contacts the filter glass.

6. The built-in filter window assembly based spatial solar spectrum polarimetry telescope according to claim 1, wherein, The relay system comprises a compensation mirror group, a 1 / 4 wave plate, a polarization beam splitter, a reimaging mirror group and a scanning mechanism arranged in sequence along an optical path, the compensation mirror group is used for aberration correction of the polarized light, the 1 / 4 wave plate is used for converting the linearly polarized light after the aberration correction into circularly polarized light, the polarization beam splitter is used for splitting the circularly polarized light, the reimaging mirror group is used for imaging the split circularly polarized light, and the scanning mechanism is used for spatial dimension scanning of the sunlight beam.

7. The built-in filter window assembly based spatial solar spectrum polarimetric telescope according to claim 6, characterized in that, The compensation mirror group comprises first to fourth lenses, and specific optical parameters are as follows: The first lens has a light passing aperture of 70mm, an Abbe number of 67.80 and a negative optical power; The second lens has a light passing aperture of 75mm, an Abbe number of 27.53 and a positive optical power; The third lens has a light passing aperture of 80mm, an Abbe number of 27.53 and a negative optical power; The fourth lens has a light passing aperture of 85mm, an Abbe number of 64.17 and a positive optical power; The distance between the first lens and the second lens is 6mm; The distance between the second lens and the third lens is 40mm; The distance between the third lens and the fourth lens is 1mm; The extinction ratio of the polarization beam splitter is 5000:1; The reimaging mirror group comprises fifth to eighth lenses, and specific optical parameters are as follows: The fifth lens has a light passing aperture of 80mm, an Abbe number of 64.17 and a negative optical power; The sixth lens has a light passing aperture of 82mm, an Abbe number of 27.60 and a positive optical power; The seventh lens has a light passing aperture of 80mm, an Abbe number of 27.60 and a negative optical power; The eighth lens has a light passing aperture of 100mm, an Abbe number of 64.17 and a positive optical power; The distance between the fifth lens and the sixth lens is 4mm; The distance between the sixth lens and the seventh lens is 22mm; The distance between the seventh lens and the eighth lens is 40mm.

8. The built-in filter window assembly based spatial solar spectrum polarimetry telescope according to claim 7, characterized in that, The relay system further comprises a plane mirror arranged between the polarization beam splitter and the reimaging lens group, and the circularly polarized light after the beam splitting is reflected by the plane mirror and then incident on the reimaging lens group.

9. The built-in filter window assembly based spatial solar spectrum polarimetry telescope according to claim 1, characterized in that, The spectral imaging system comprises a slit, a spectrometer and a photodetector, and the light beam transmitted by the relay system converges at the slit and then is dispersed by the spectrometer and imaged on the photodetector.

Images