A space telescope star-vanishing secondary mirror support structure and a space telescope

Abstract

The application belongs to a support structure, and aims at the technical problem that the existing curve type secondary mirror support mainly adopts an open circular arc with constant curvature, and the curve structure form and support connection form are relatively single, and provides a space telescope star ray eliminating secondary mirror support structure, a space telescope and a secondary mirror support structure. The main body of the support rib plate is a curve structure, and the projection thereof on the aperture plane perpendicular to the optical axis has a curve edge. At least one of the support rib plates is a closed ring-shaped support rib plate, an S-shaped support rib plate, a spiral-shaped support rib plate or an asymmetric arc-shaped support rib plate with the curvature changing along the extension direction thereof. The above support rib plate realizes the support connection of the secondary mirror, disperses the diffraction energy generated thereby to different angular positions, and reduces the linear star ray extending in a fixed direction.

Description

Technical Field

[0001] This application belongs to the field of space telescope technology, specifically relating to a space telescope anti-stellar mirror support structure and a space telescope. Background Technology

[0002] Space telescopes typically employ coaxial reflecting optical systems, with the secondary mirror fixed in front of the primary mirror via a support rib. The support rib is located within the effective aperture, and its obstructed edges cause diffraction, forming starbursts in point source images.

[0003] Traditional secondary mirror support structures mainly employ cross-shaped, triangular, or hexagonal straight support ribs. The regular straight lines tend to concentrate diffraction energy along specific directions by obscuring the edges. To reduce linear starburst effects, existing technologies have also proposed using open arc-shaped secondary mirror support ribs with constant curvature, arranging multiple arc-shaped support ribs at predetermined angles to disperse diffraction energy circumferentially. However, existing curved secondary mirror supports primarily use open arc configurations, resulting in relatively simple curved structural forms and support connections between the secondary mirror mount and the fixed structure. Summary of the Invention

[0004] This application addresses the technical problem that existing curved secondary mirror supports mainly adopt open circular arcs with constant curvature, and the curved structure and support connection methods are relatively simple. It provides a space telescope stellar-eliminating secondary mirror support structure and a space telescope.

[0005] To achieve the above objectives, this application adopts the following technical solution: In a first aspect, this application proposes a secondary mirror support structure for a space telescope, comprising a secondary mirror mount for mounting the secondary mirror and at least one support rib disposed between the secondary mirror mount and the fixed structure of the space telescope, wherein the support rib constitutes a support connection between the secondary mirror mount and the fixed structure; the main body of the support rib is a curved structure, and the projection of the support rib onto the aperture plane perpendicular to the optical axis has a curved edge. At least one of the supporting ribs is a closed annular supporting rib, an S-shaped supporting rib, a spiral supporting rib, or an asymmetric arc-shaped supporting rib, wherein the curvature of the asymmetric arc-shaped supporting rib varies along its own extension direction.

[0006] Furthermore, the fixing structure is a camera lens hood structure; the number of the closed annular support ribs is one or more, and the projection of each closed annular support rib on the aperture plane is a circular ring or an elliptical ring.

[0007] Furthermore, there are multiple closed annular support ribs, which have different sizes and are disposed at different positions around the secondary mirror mount.

[0008] Furthermore, there are multiple supporting ribs, each of which is an S-shaped supporting rib and is distributed radially. Each S-shaped supporting rib extends from the secondary mirror mount to the fixed structure, and the overall rotation direction of each S-shaped supporting rib is the same or alternately arranged.

[0009] Furthermore, the supporting rib is a spiral supporting rib, which extends outward from the secondary mirror mount in both the radial and circumferential directions to the fixed structure.

[0010] Furthermore, the number of the supporting ribs is multiple, and the multiple supporting ribs include a closed ring supporting rib and at least one arc-shaped supporting rib disposed inside the closed ring supporting rib. The arc-shaped supporting rib connects the secondary mirror base to the closed ring supporting rib, and the closed ring supporting rib is connected to the fixed structure.

[0011] Furthermore, there are multiple asymmetric arc-shaped support ribs, and different asymmetric arc-shaped support ribs have different curve profiles.

[0012] Furthermore, the thickness of the supporting rib along the optical axis is set according to the structural stiffness requirements of the space telescope's stellar-reducing secondary mirror support structure.

[0013] Furthermore, the fixing structure is one of the following: a telescope primary mirror, a telescope barrel, or a camera lens hood structure.

[0014] Secondly, this application proposes a space telescope, including a secondary mirror and a fixed structure, and also includes the aforementioned space telescope anti-stellar effect secondary mirror support structure, wherein the secondary mirror is mounted on the secondary mirror mount.

[0015] Compared with the prior art, this application has the following beneficial effects: This application proposes a secondary mirror support structure for space telescopes to reduce stellar rays. It employs closed ring-shaped, S-shaped, spiral, or asymmetric arc-shaped support ribs with curvature varying along the extension direction, forming a curved support connection between the secondary mirror mount and the fixed structure, distinct from a single open circular arc. These support ribs form closed, reversed, spiral, or variable-curvature curved edges within the aperture plane, causing the direction of each local edge to change with position. This disperses the diffraction energy generated by the support ribs to different angular positions, reducing the bright linear stellar rays extending along the fixed direction. Simultaneously, different curved support configurations can create corresponding load-bearing paths between the secondary mirror mount and the fixed structure, thus supporting the secondary mirror. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of a cross-shaped secondary mirror support structure in the prior art.

[0018] Figure 2 This is a schematic diagram of a trident-shaped secondary mirror support structure in the prior art.

[0019] Figure 3 This is a schematic diagram of a hexagonal secondary mirror support structure in the prior art.

[0020] Figure 4 This is a schematic diagram of an open arc-shaped secondary mirror support structure in the prior art.

[0021] Figure 5 This is a schematic diagram of the S-shaped support structure in an embodiment of this application.

[0022] Figure 6 This is a schematic diagram of the ring support structure in an embodiment of this application.

[0023] Figure 7 This is an illustration of Sirius as seen by the Hubble Space Telescope.

[0024] Figure 8 This is a schematic diagram of the starburst effect produced by an existing linear secondary mirror support structure.

[0025] Figure 9 This is a schematic diagram of the diffraction effect of an existing open circular arc-shaped secondary mirror support structure.

[0026] Figure 10 This is a schematic diagram illustrating the effect of the S-shaped support structure in eliminating starburst effects in the embodiments of this application.

[0027] Figure 11 This is a schematic diagram illustrating the effect of the annular support structure in eliminating starburst effects in the embodiments of this application. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0030] To clearly illustrate the technical problem addressed by this application, before providing a detailed description of the support structure for the space telescope's stellar-reducing secondary mirror, we will first combine... Figures 1 to 3 A necessary introduction to the existing secondary mirror support structure is provided.

[0031] Space telescopes are essential scientific instruments for astronomical observation and deep space exploration. To achieve high imaging resolution, space telescopes typically employ coaxial reflecting optical systems, such as the Cassegrain optical system. In this type of optical system, the secondary mirror is positioned in front of the primary mirror and held in a predetermined optical position by a secondary mirror support structure. Because the secondary mirror support structure is located within the effective aperture of the space telescope, incident light rays undergo diffraction as they pass through the edges of the secondary mirror support structure. For point sources such as stars, this diffraction phenomenon manifests on the imaging plane as bright fringes extending outward from the center of the point source, i.e., starbursts.

[0032] The secondary mirror support structure of existing coaxial reflecting space telescopes typically uses straight support ribs. For example... Figure 1 As shown, the existing cross-shaped secondary mirror support structure consists of two sets of mutually perpendicular straight support ribs. Figure 1 The image shows a symmetrical cross arrangement and a cross arrangement formed after overall rotation. Both arrangements have straight, continuous blocking edges extending in a fixed direction.

[0033] like Figure 2 As shown, the existing triangular secondary mirror support structure consists of three straight support ribs, with an included angle of approximately 120° between adjacent straight support ribs. Figure 2 The different arrangements all belong to the three-pronged linear support structure, and the main difference lies in the overall angular position.

[0034] like Figure 3 As shown, the existing hexagonal secondary mirror support structure consists of six straight support ribs, and can also be regarded as a combination or variation of two three-pronged straight support structures. The six straight support ribs extend from the area where the secondary mirror is located to the periphery of the aperture, forming six sets of straight shielding edges with fixed directions within the aperture plane.

[0035] Existing linear support ribs form regular linear blocking edges in the aperture function. According to the principles of Fourier optics, the far-field diffraction pattern is determined by the Fourier transform of the aperture function. Continuously distributed linear blocking edges along the same direction concentrate diffraction energy primarily in the direction perpendicular to the blocking edge, forming bright and elongated starburst fringes on the imaging plane. For example, a cross-shaped secondary mirror support structure typically forms a four-pointed starburst, while a triangular secondary mirror support structure typically forms a six-pointed starburst.

[0036] The brightness of the aforementioned starburst fringes may be significantly higher than the surrounding background brightness. When nebulae, exoplanets, or other faint celestial objects are located along the extension path of the starburst fringes, the signals of these faint objects are easily obscured or interfered with by the starburst fringes. Simultaneously, strong starbursts can compress the effective dynamic range of an image, increasing the difficulty of subsequent astronomical image processing and faint target identification. To reduce the linear starbursts generated by straight support ribs, existing technologies have proposed using open circular arc support ribs with constant curvature, arranging multiple open circular arc support ribs at predetermined angles to disperse the diffraction energy generated at the edges of each arc circumferentially. However, this type of curved support mainly adopts an open circular arc configuration, and its curved structural form and the support connection form formed between the secondary mirror mount and the fixed structure are relatively simple. Based on this, this application provides closed ring, S-shaped, spiral, and asymmetric arc-shaped secondary mirror support structures with curvature varying along their own extension direction.

[0037] The space telescope anti-stellar effect secondary mirror support structure of this application includes a secondary mirror mount for mounting the secondary mirror and at least one support rib disposed between the secondary mirror mount and the space telescope fixing structure. The support rib forms a support connection between the secondary mirror mount and the fixing structure. The main body of the support rib is a curved structure, and the projection of the support rib onto the aperture plane perpendicular to the optical axis of the space telescope has a curved edge. The support rib is a closed ring support rib, an S-shaped support rib, a spiral support rib, or an asymmetric arc support rib, and the curvature of the asymmetric arc support rib varies along its own extension direction.

[0038] In a structure where the supporting rib directly connects the secondary mirror mount to the fixed structure, the connection area of ​​the supporting rib near the secondary mirror mount is connected to the secondary mirror mount, and the connection area of ​​the supporting rib near the fixed structure is connected to the fixed structure. In a combined support structure, an arc-shaped supporting rib located inside a closed-ring supporting rib connects the secondary mirror mount to the closed-ring supporting rib, and the closed-ring supporting rib is connected to the fixed structure, thus forming a support connection between the secondary mirror mount and the fixed structure. The inertial load, assembly load, and other loads generated during operation borne by the secondary mirror are first transferred to the secondary mirror mount, and then transferred to the fixed structure through the supporting rib, keeping the secondary mirror in a predetermined position relative to the optical axis of the space telescope. When the space telescope is operating, both the secondary mirror and the supporting rib will block the incident beam. The projection shape of the supporting rib on the aperture plane can change the distribution of diffraction energy on the imaging plane. Because the supporting rib has curved edges, the curved edges have different local tangent directions and local normal directions at different positions, and the diffraction energy generated by each local edge is distributed in different directions accordingly. By employing closed-loop, S-shaped, spiral, or variable-curvature asymmetric arc-shaped support ribs, the diffraction energy generated by the support ribs can be dispersed to different angular positions while maintaining the secondary mirror support function, thus reducing the linear starburst extending along a fixed direction.

[0039] In one embodiment of this application, the space telescope includes a secondary mirror, a secondary mirror mount for mounting the secondary mirror, a fixing structure, and a space telescope stellar-reducing secondary mirror support structure disposed between the secondary mirror mount and the fixing structure.

[0040] Space telescopes can employ coaxial reflective optical systems. The secondary mirror is mounted in front of the primary mirror via a secondary mirror mount and maintains a predetermined positional relationship with the optical axis of the space telescope. The fixing structure can be a primary mirror, telescope tube, or camera hood structure, depending on the specific construction of the space telescope. The supporting ribs connect to the secondary mirror mount at the connection area near the secondary mirror mount, and connect to the fixing structure at the connection area away from the secondary mirror mount.

[0041] This application does not limit the specific connection process between the support stiffener and the secondary mirror mount and fixing structure. While ensuring connection strength, positional stability, and adaptability to the space environment, the support stiffener can form an integral structure with the secondary mirror mount or fixing structure, or it can adopt a connection structure suitable for space telescope assembly.

[0042] The supporting ribs are located within the effective aperture region of the space telescope, and their projection onto the aperture plane perpendicular to the optical axis contributes to the formation of the space telescope's actual aperture function. This application employs closed-loop, S-shaped, spiral, or variable-curvature asymmetrical arc-shaped supporting ribs to create closed, reversed, spiral, or variable-curvature curved edges within the aperture plane, thereby altering the obstruction pattern of the supporting structure on the effective aperture.

[0043] When the space telescope is subjected to launch loads, on-orbit attitude adjustment loads, or other external forces, the load borne by the secondary mirror is transferred through the secondary mirror mount to the support ribs, and then through the support ribs to the fixed structure. The curved shape of the support ribs does not change their basic load-bearing function of connecting the secondary mirror mount and the fixed structure. By rationally determining the curvature, number, spatial distribution, and optical axis dimensions of the support ribs, both the structural support requirements and the requirements for eliminating starburst effects of the secondary mirror can be met.

[0044] In contrast, existing secondary mirror support ribs can employ an open, arc-shaped structure. This arc-shaped structure can be semi-circular, C-shaped, or crescent-shaped, with its arc segments forming continuous, smooth curves. One end of the arc-shaped support rib connects to the secondary mirror mount, and the other end connects to the outer fixing structure, creating an open arc-shaped support path between the secondary mirror mount and the fixing structure. The projections of the two sides of the arc-shaped support rib onto the aperture plane form corresponding curved edges. For example... Figure 4 As shown, multiple meniscus-shaped support ribs can be distributed around the secondary mirror mount and extend from the area of ​​the secondary mirror mount outwards from the aperture. Each arc edge has different local tangent and local normal directions at different locations, thus dispersing diffraction energy to different angular positions. This open arc-shaped support structure is used as a prior art comparison to illustrate the influence of the curved edges on the diffraction energy distribution.

[0045] Example 1 There are multiple supporting stiffeners, all of which are S-shaped and radially distributed around the secondary mirror mount. Each S-shaped supporting stiffener extends from the secondary mirror mount toward the fixed structure.

[0046] like Figure 5 As shown, four or three S-shaped support ribs can be installed. The end of each S-shaped support rib near the center is connected to the secondary mirror mount, and the end near the outer edge of the aperture is connected to the fixing structure. The bending direction of the S-shaped support rib changes as it extends outward from the secondary mirror mount, so that its edge forms a continuously changing curved profile on the aperture plane.

[0047] The overall rotation direction of multiple S-shaped support ribs can be the same. When the overall rotation direction of each S-shaped support rib is the same, the multiple S-shaped support ribs form a consistent rotation direction around the secondary mirror mount, so that the overall aperture blocking contour is distributed in a rotational manner.

[0048] Optionally, the overall rotation direction of adjacent S-shaped support stiffeners can also be alternated. When using an alternate overall rotation direction, the directional distribution of the curve edges in different angular areas can be changed, and the cooperative bearing relationship between each S-shaped support stiffener can be adjusted according to the stress condition of the secondary mirror mount.

[0049] The S-shaped support rib replaces the long, straight edge of the traditional straight support rib with a curved edge that changes continuously in local direction. When incident light passes through the curved edge, the diffraction components formed at different positions are dispersed to different angular positions, thereby reducing the concentration of bright linear starbursts.

[0050] Example 2 The fixed structure adopts a camera lens hood structure, and the supporting ribs are one or more closed annular supporting ribs. The projection of the closed annular supporting ribs on the aperture plane can be a circular ring or an elliptical ring.

[0051] Figure 6 One type of structure features two circular closed-ring support ribs, located on either side of the secondary mirror mount. The local area of ​​each circular closed-ring support rib near the secondary mirror mount is connected to the secondary mirror mount, while the local area near the outer edge of the aperture is connected to the camera lens hood structure.

[0052] Figure 6 Another structural feature includes three elliptical closed-ring support ribs distributed around the secondary lens mount. A portion of each elliptical closed-ring support rib is connected to the secondary lens mount, while another portion is connected to the camera lens hood structure.

[0053] The closed annular support rib extends continuously along its circumference, forming an annular load-bearing structure between the secondary mirror mount and the fixed structure. The shielding boundary of the closed annular support rib on the aperture plane is mainly composed of circular or elliptical curves, and does not have a long straight shielding edge that extends directly radially from the secondary mirror mount to the outer perimeter of the aperture.

[0054] The local tangent and normal directions on a circular or elliptical ring change continuously along the ring path. Therefore, the diffraction components formed at each local edge can be distributed in multiple directions. The diffraction pattern produced by a closed ring support rib can appear as a diffuse halo, a ring-shaped energy distribution, or a petal-shaped energy distribution related to the symmetry of the ring structure, rather than forming the bright, slender straight starbursts corresponding to traditional straight support ribs.

[0055] In other embodiments of this application, the support ribs may optionally adopt a helical structure. The helical support ribs extend radially and circumferentially outwards from near the secondary mirror mount and are connected to the fixed structure. The projection of the helical support ribs onto the aperture plane is continuously curved along the helical direction, causing the local orientation of the support rib edges to change with the helical extension position. By adjusting the direction of rotation, number of turns, extension range, and quantity of the helical support ribs, the angular distribution of diffraction energy can be further adjusted.

[0056] In one embodiment of this application, the plurality of support ribs include a closed annular support rib and at least one arc-shaped support rib disposed inside the closed annular support rib. The arc-shaped support rib connects the secondary mirror mount to the closed annular support rib, and the closed annular support rib is connected to the fixed structure, thereby jointly forming a support connection between the secondary mirror mount and the fixed structure.

[0057] The arc-shaped support rib can be a relatively short curved structure to avoid forming a long straight obstruction edge that penetrates the effective aperture inside the closed annular support rib. The load borne by the secondary mirror mount can be transferred first through the arc-shaped support rib to the closed annular support rib, and then from the closed annular support rib to the fixed structure, thus forming a graded load-bearing path.

[0058] Optionally, the curved structure of the supporting ribs can be an asymmetrical arc structure. The asymmetrical arc-shaped supporting ribs have a non-uniform curvature change along their extension direction, or different supporting ribs use different curve profiles, so that the shielding edges in the aperture plane do not have a strict rotational symmetry relationship. Based on the stray light suppression requirements of the space telescope, the asymmetrical curve profile can be used to adjust the diffraction energy distribution in a specific angular region.

[0059] Optionally, there can be multiple closed-ring support ribs, which have different sizes and are positioned at different locations around the secondary mirror mount to form a multi-layered ring structure. Multiple closed-ring support ribs can also be combined with arc-shaped or spiral support ribs.

[0060] The thickness of the supporting stiffener is set according to the structural stiffness requirements of the space telescope's stellar-reducing secondary mirror support structure. The thickness of the supporting stiffener is its dimension along the optical axis, not the width or curvature of its curve within the aperture plane.

[0061] While keeping the projected shape of the support rib's aperture plane essentially unchanged, increasing the rib's dimension along the optical axis can improve its bending stiffness and overall structural stiffness. Since adjusting the dimension along the optical axis does not directly change the curved obscuring edge into a straight one, the impact of reasonably adjusting this thickness on the starburst shape is generally less than the impact of changing the main shape of the support rib within the aperture plane.

[0062] In the actual design process, the thickness of the support stiffeners can be determined by taking into account the secondary mirror quality, mechanical loads during launch, on-orbit operational stability, structural natural frequency, and thermal stability requirements.

[0063] The material for the support ribs can be selected based on the mechanical properties and thermal stability requirements of the space telescope. Closed-loop support ribs, S-shaped support ribs, spiral support ribs, asymmetric arc support ribs, and arc support ribs in combined support structures can be manufactured using electroforming, CNC machining, or other precision machining methods capable of forming continuous curved edges. These machining methods are optional and do not constitute the sole limitation on the material and manufacturing process of the support ribs.

[0064] When a space telescope is in operation, the incident light beam enters the optical system through the effective aperture area defined by the primary mirror, telescope tube, or camera shield structure. The secondary mirror and support ribs partially block the incident light beam, so that the actual aperture function includes the central blocking area and the projection area of ​​the support ribs.

[0065] Diffraction originates from the wave nature of light. Diffraction occurs when light crosses the obstruction edge of a secondary mirror or supporting rib. As long as a coaxial reflecting space telescope contains a secondary mirror and its supporting structure, causing the actual aperture function to differ from a standard circular aperture without obstruction, the diffraction effect will exist. This application does not completely eliminate the diffraction effect in a physical sense, but rather adjusts the spatial distribution of diffraction energy by changing the geometry of the obstruction edge of the supporting rib.

[0066] like Figure 7 As shown, when the Hubble Space Telescope images Sirius A, bright fringes extending outward along several fixed directions are formed around Sirius A, while Sirius B is located in the lower left of the image. This imaging result indicates that in coaxial reflecting space telescopes, the secondary mirror and its support structure can obstruct the effective aperture, causing the actual aperture function to differ from a standard circular aperture without central or support obstruction. Incident light undergoes diffraction when crossing the edges of the secondary mirror and support ribs; therefore, as long as a secondary mirror support structure exists within the effective aperture, a diffraction energy distribution corresponding to the projected shape of that support structure will form on the imaging surface.

[0067] The diffraction phenomenon does not completely disappear physically simply by using curved support ribs. This application reduces the bright, elongated, and directional starbursts in the imaging results by changing the projection edge of the support ribs on the aperture plane, thus preventing the diffraction energy from being highly concentrated along a few fixed directions.

[0068] For a square aperture with regular straight edges, its diffraction intensity distribution can be expressed by the following formula:

[0069] For a circular aperture, its diffraction intensity distribution can be expressed by the following formula:

[0070] Where I(x,y) represents the diffraction intensity at coordinates x and y on the imaging surface, I(r) represents the diffraction intensity at a radial distance r from the central spot, I0 represents the central reference intensity, D represents the characteristic size of the aperture, λ represents the incident light wavelength, f represents the equivalent focal length of the optical system, J1 represents the first-order Bessel function of the first kind, and sinc represents the Singer function.

[0071] The regular straight edges corresponding to the first formula give the aperture function a strong directionality in different directions, thus easily forming diffraction fringes extending along a fixed direction on the imaging plane. The circular aperture corresponding to the second formula does not have straight edges with a fixed direction, and its diffraction intensity is mainly distributed radially. For space telescopes equipped with secondary mirror mounts and support ribs, the primary aperture, the secondary mirror blocking area, and the projection area of ​​the support ribs on the aperture plane can be collectively used to construct a two-dimensional aperture function.

[0072] The two-dimensional aperture function, after Fourier transform, forms a far-field complex amplitude distribution. The square of the modulus of the far-field complex amplitude forms the diffraction intensity distribution on the imaging plane. When the number of supporting ribs, the projection shape, the edge direction, and the circumferential arrangement change, the two-dimensional aperture function changes accordingly, ultimately forming diffraction patterns of different shapes.

[0073] like Figure 8 As shown, the aperture functions formed by the cross-shaped, triangular, and hexagonal linear secondary mirror support structures are simulated respectively. Figure 8 The cross-shaped, trident-shaped, and hexagonal support structures are all existing linear secondary mirror support structures, used in conjunction with... Figures 9 to 11 The diffraction effects of the curved secondary mirror support structure shown are compared. Among them, Figure 9 The open arc-shaped support structure shown is a prior art comparison structure. Figure 10 and Figure 11 The S-shaped support structure and the closed ring support structure shown are secondary mirror support structures of this application.

[0074] The cross-shaped secondary mirror support structure has mutually perpendicular straight blocking edges, and its diffraction pattern forms bright starbursts extending along the intersecting directions. The three straight ribs of the trident-shaped secondary mirror support structure are approximately 120° apart, and the corresponding diffraction pattern forms six main starburst directions. The adjacent ribs of the hexagonal secondary mirror support structure can be distributed at approximately 60°, and the corresponding diffraction pattern forms more numerous and regularly distributed bright fringes in the angular direction.

[0075] Depend on Figure 8It can be seen that the number and angular position of the linear support ribs can change the number and extension direction of the starbursts, but cannot prevent the diffraction energy from concentrating along a fixed direction. The linear support ribs form long straight edges with an unchanged direction on the aperture plane, and the diffraction components generated at each position are easily superimposed along the corresponding direction, thus forming bright and continuous linear starbursts.

[0076] This application employs closed-loop, S-shaped, spiral, or variable-curvature asymmetric arc-shaped support ribs, causing the local tangent and normal directions at the edges of the support ribs to change with their extension position. The diffraction components generated by the curved edges at different locations are correspondingly distributed in different directions, reducing the continuous superposition of multiple diffraction components in the same fixed direction. Thus, the high-intensity linear energy originally concentrated in a few directions is dispersed over a wider angular range, manifesting as low-intensity diffuse light, ring light, or lobe light on the imaging plane.

[0077] like Figure 9 As shown, simulations are performed on existing open arc-shaped support structures with four and three semi-circular or crescent-shaped support ribs, respectively. Each support rib extends from the area where the secondary mirror mount is located towards the periphery of the aperture, and the projection edge of the support rib on the aperture plane is a smooth curve. Figure 8 Compared to the linear secondary mirror support structure shown, Figure 9 The energy in the diffraction pattern shown is mainly distributed around the central spot, and no bright, straight starbursts extending over long distances along a few fixed directions are formed.

[0078] Figure 9 This is used to illustrate the influence of existing open circular arc support structures and curved edges on the angular distribution of diffraction energy. Figure 9 The semi-circular or crescent-shaped support ribs shown do not belong to the closed-circular, S-shaped, spiral, or variable-curvature asymmetric arc support ribs currently claimed in this application.

[0079] like Figure 10 As shown, simulations were performed on the aperture functions formed by structures with four and three S-shaped support ribs, respectively. Each S-shaped support rib extends from the secondary mirror mount towards the periphery of the aperture, forming a continuously changing curved profile during the extension process. The edge direction of the S-shaped support rib changes multiple times along its length, causing the diffraction energy generated at each local edge to be dispersed to different angular positions.

[0080] Figure 10 In the diffraction pattern shown, there is relatively dispersed low-intensity light energy around the central spot, and the bright linear starburst extending continuously along a single fixed direction is weakened. The specific distribution of the diffraction pattern differs when four S-shaped support ribs are set versus three S-shaped support ribs, indicating that the number, bending direction, and circumferential arrangement of the support ribs can be used to adjust the distribution of diffraction energy.

[0081] like Figure 11 As shown, one structure has two circular closed-ring support ribs, which are respectively arranged on both sides of the secondary mirror base; another structure has three elliptical closed-ring support ribs, which are distributed around the secondary mirror base.

[0082] The aperture edges formed by the two circular closed-ring support ribs change continuously along the circumference, and their diffraction energy is mainly manifested as a ring-shaped or diffuse distribution around the central spot, without forming bright, slender starbursts produced by long, straight-line blocking edges. The diffraction pattern formed by the three elliptical closed-ring support ribs has a petal-like distribution related to the number of elliptical rings, the direction of the major and minor axes, and the circumferential arrangement, but its energy no longer forms a continuous high-intensity convergence along a few straight lines.

[0083] Figures 9 to 11 The results show that the support ribs with curved edges can alter the angular distribution of diffraction energy. Specifically, Figure 9 The open arc-shaped support structure shown is a comparative structure of existing technology; Figure 10 and Figure 11 The S-shaped support ribs, circular closed-ring support ribs, and elliptical closed-ring support ribs shown are secondary mirror support structures of this application. The curved support ribs of this application do not cause the diffraction energy to disappear, but rather transform the diffraction energy from a high-intensity linear distribution in a few directions to a diffuse, ring-shaped, or petal-shaped distribution with lower intensity around the central spot.

[0084] In one application example of this application, a space telescope is used to observe faint nebulae, exoplanets, or other faint celestial objects near bright stars. Depending on the overall structure of the space telescope, closed annular support ribs, S-shaped support ribs, spiral support ribs, or asymmetric arc-shaped support ribs with curvature varying along their own extension direction can be provided between the secondary mirror mount and the telescope primary mirror, telescope tube, or camera shield structure.

[0085] Figures 8 to 11 The simulations shown can use the same main aperture size, central occlusion ratio, incident light wavelength, equivalent focal length, supporting rib projection width, sampling resolution, and intensity normalization conditions to compare the effects of different secondary mirror support structures on diffraction energy distribution. This application does not impose uniform numerical limitations on the above parameters; in practical applications, they can be set in conjunction with the optical parameters of the space telescope, the aperture size, and the actual dimensions of the secondary mirror support structure.

[0086] In one application example of this application, a space telescope is used to observe faint nebulae, exoplanets, or other faint celestial objects near bright stars. Depending on the overall structure of the space telescope, closed annular support ribs, S-shaped support ribs, spiral support ribs, or asymmetric arc-shaped support ribs with curvature varying along their own extension direction can be provided between the secondary mirror mount and the telescope primary mirror, telescope tube, or camera shield structure.

[0087] To meet the requirements for secondary mirror support stiffness and thermal stability, the number, curvature, circumferential position, and thickness along the optical axis of the support ribs can be determined based on the effective aperture range, secondary mirror mount dimensions, and the location of the external fixing structure. After assembly, the support ribs provide structural support to the secondary mirror mount and form a curved shielding edge within the aperture plane.

[0088] When a space telescope images a high-brightness light source, the curved support ribs disperse the diffraction energy generated by the support and shielding around the central light spot, reducing the bright linear starbursts extending along a few fixed directions. Therefore, faint target signals located near the high-brightness light source or along the original path of the starburst are less likely to be completely obscured by continuous bright fringes.

[0089] This application example does not limit the specific model of the space telescope, the observation band, the exposure time, the main aperture size, the central obstruction ratio, or the image processing method. The above parameters can be set according to the actual observation target and the optical system of the space telescope.

[0090] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A secondary mirror support structure for a space telescope, comprising a secondary mirror mount for mounting the secondary mirror and at least one support rib disposed between the secondary mirror mount and a fixed structure of the space telescope, the support rib forming a support connection between the secondary mirror mount and the fixed structure; characterized in that, The main body of the supporting rib is a curved structure, and the projection of the supporting rib on the aperture plane perpendicular to the optical axis has a curved edge. At least one of the supporting ribs is a closed annular supporting rib, an S-shaped supporting rib, a spiral supporting rib, or an asymmetric arc-shaped supporting rib, wherein the curvature of the asymmetric arc-shaped supporting rib varies along its own extension direction.

2. The space telescope anti-stellar mirror support structure according to claim 1, characterized in that, The fixing structure is a camera lens hood structure; the number of the closed annular support ribs is one or more, and the projection of each closed annular support rib on the aperture plane is a circular ring or an elliptical ring.

3. The space telescope anti-stellar mirror support structure according to claim 2, characterized in that, The number of closed annular support ribs is multiple, and the multiple closed annular support ribs have different sizes and are arranged at different positions around the secondary mirror mount.

4. The space telescope anti-stellar mirror support structure according to claim 1, characterized in that, The number of supporting ribs is multiple, and each of the supporting ribs is an S-shaped supporting rib distributed radially. Each of the S-shaped supporting ribs extends from the secondary mirror mount to the fixed structure, and the overall rotation direction of each of the S-shaped supporting ribs is the same or alternately arranged.

5. The space telescope anti-stellar mirror support structure according to claim 1, characterized in that, The supporting rib is a spiral supporting rib, which extends outward from the secondary mirror base in both radial and circumferential directions to the fixed structure.

6. The space telescope anti-stellar mirror support structure according to claim 1, characterized in that, The number of the supporting ribs is multiple, including a closed ring supporting rib and at least one arc-shaped supporting rib disposed inside the closed ring supporting rib. The arc-shaped supporting rib connects the secondary mirror mount to the closed ring supporting rib, and the closed ring supporting rib is connected to the fixed structure.

7. The space telescope anti-stellar mirror support structure according to claim 1, characterized in that, There are multiple asymmetric arc-shaped support ribs, and different asymmetric arc-shaped support ribs have different curve profiles.

8. The space telescope anti-stellar mirror support structure according to claim 1, characterized in that, The thickness of the supporting rib along the optical axis is set according to the structural stiffness requirements of the space telescope's stellar-reducing secondary mirror support structure.

9. The space telescope anti-stellar mirror support structure according to claim 1, characterized in that, The fixing structure is one of the following: the telescope primary mirror, the telescope barrel, or the camera lens hood structure.

10. A space telescope, comprising a secondary mirror and a fixed structure, characterized in that, It also includes the space telescope stellar-reducing secondary mirror support structure according to any one of claims 1 to 9, wherein the secondary mirror is mounted on the secondary mirror mount.

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