General surface shape detection method for different telescope primary mirror sub-mirror

Abstract

The application discloses a universal surface shape detection method for different telescope primary mirror spliced sub-mirrors, which adopts a selected parameter focusing single lens to shorten the detection light path length of different telescope off-axis sub-mirrors, and residual wave aberration of detection light path inspection points of each sub-mirror is borne by a computer holography compensation. When detecting different telescope spliced sub-mirrors, a corresponding calibration light path is designed, a special standard spherical mirror is selected, and transmission wave front error introduced by focusing lens processing is calibrated; and a light ray tracing mode is adopted to obtain transmission wave front of a corresponding region of the measured mirror and the focusing lens. The application is a universal detection method, has the characteristics of simple structure and strong universality, can be applied to surface shape detection of a plurality of large astronomical telescope primary mirror spliced sub-mirrors, effectively avoids complicated customization of different telescope sub-mirror surface shape detection equipment, reduces manufacturing cost of different parameter sub-mirrors, and provides theoretical and technical support for diversified design of large astronomical telescopes.

Description

Technical Field

[0001] This invention belongs to the field of advanced optical manufacturing and testing, specifically involving a general testing method for the high-precision surface shape of spliced ​​sub-mirrors of different large astronomical optical telescopes. Background Technology

[0002] With the deepening of space exploration, the demand for large astronomical telescopes is increasing both domestically and internationally, leading to the proposal of construction plans for large astronomical telescopes with different apertures. Domestically, proposed telescopes include the Large Optical Telescope (LOT) at 12 meters, the Expanding Aperture Segmented Telescope (EAST) at 12 meters, and the Jiaotong University Spectroscopic Telescope (JUST) at 12 meters, 8 meters, and 4.4 meters respectively, with primary mirror radii of curvature of 38.4 meters, 21.5 meters, and 12.8 meters respectively. Internationally, telescopes currently under construction include the Thirty-Meter Telescope (TMT) in the United States and the Extremely Large Telescope (ELT) in Europe at 12 meters and 39.2 meters respectively, with primary mirror radii of curvature of 60 meters and 69 meters respectively. The primary mirrors of these telescopes with different apertures are all composed of hexagonal sub-mirrors with a diagonal diameter of 1.1 meters or 1.44 meters.

[0003] The aspherical primary mirror of a mosaic telescope is composed of hundreds of sub-mirrors. The basic optical parameters of the primary mirror, including aperture, vertex radius of curvature, aspherical coefficient, and surface shape error, are uniquely determined according to the specific requirements of the telescope. The sub-mirrors that make up the mosaic mirror do not have exactly the same parameters. To achieve co-phase mosaicking of the telescope's primary mirror, the shape, aperture, splicing position, off-axis distance, surface shape, and surface shape error must simultaneously meet technical requirements.

[0004] The high-precision surface shape inspection of the splicing sub-mirrors of telescope primary mirrors employs a method of shortening the detection optical path length using an achromatic single lens, and using a computer-generated hologram (CGH) to compensate for residual wave aberrations in the detection optical path. However, when mass-producing splicing sub-mirrors for different types of astronomical telescopes, the primary mirror curvature radii vary, and designing and constructing a detection optical path for each type of splicing sub-mirror is undoubtedly time-consuming and labor-intensive. How to complete the rapid inspection of different telescope splicing sub-mirrors quickly and efficiently has become an urgent technical challenge to be solved in the field of astronomical telescope manufacturing. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention provides a universal surface shape detection method for splicing sub-mirrors of different telescope primary mirrors.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A general method for detecting the surface shape of spliced ​​sub-mirrors from different telescope primary mirrors includes the following steps:

[0008] Step 1: Construct the first calibration optical path for the first telescope primary mirror splicing sub-mirror. This first calibration optical path includes an interferometer, a first computational hologram, a zoom lens, and a first standard mirror corresponding to the first telescope (the first standard mirror is a standard spherical mirror; the radius of curvature of the standard spherical mirror varies depending on the telescope, but is the same as the radius of curvature of the primary mirror of the specific telescope). The outgoing light from the interferometer is diffracted by the first computational hologram and transmitted through the zoom lens, then incident perpendicularly to the first standard mirror. The light is then reflected along the original optical path back to the interferometer. The wavefront of the returning light interferes with the reference wavefront inside the interferometer, forming interference fringes. The transmission wavefront error W of the zoom lens in the first calibration optical path is obtained after processing by the interferometer software. 1-0 The transmission wavefront of the first calibration optical path is transformed by ray tracing to obtain the transmission wavefront W1 of the corresponding region of the first calibration optical path of the off-axle mirror of the first telescope.

[0009] Step 2: Construct the first detection optical path of the first telescope primary mirror splicing sub-mirror. Replace the first standard mirror in the first calibration optical path with the first telescope off-axis sub-mirror, and replace the first computational hologram with the second computational hologram. The outgoing light from the interferometer is diffracted by the second computational hologram and transmitted through a zoom lens, and then incident perpendicularly on the first telescope off-axis sub-mirror. After that, the light is reflected along the original optical path and returns to the interferometer. Measure the wavefront W2 of the first detection optical path of the first telescope off-axis sub-mirror (processed and calculated by the interferometer software; the measurement method is the same as the measurement method of W1 above).

[0010] Step 3: Calculate the surface shape of the first telescope away from the axion mirror, i.e., W3 = W2 - W1;

[0011] Step 4: Construct the second calibration optical path for the primary mirror splicing sub-mirror of the second telescope. Replace the off-axis sub-mirror of the first telescope with the corresponding second standard mirror of the second telescope at the position of the first standard mirror, and replace the second computational hologram with the third computational hologram. The outgoing light from the interferometer is diffracted by the third computational hologram and transmitted through the zoom lens, then incident perpendicularly to the second standard mirror. After that, the light is reflected along the original optical path and returns to the interferometer. The wavefront of the returning light interferes with the reference wavefront inside the interferometer, forming interference fringes. After processing, the transmission wavefront error W of the zoom lens in the second calibration optical path is obtained. 4-0The transmission wavefront of the second calibration optical path is transformed by using ray tracing to obtain the transmission wavefront W4 of the corresponding region of the second calibration optical path of the off-axle mirror of the second telescope.

[0012] Step 5: Construct the second detection optical path of the second telescope primary mirror splicing sub-mirror. The second detection optical path replaces the second standard mirror in the second calibration optical path with the off-axis sub-mirror of the second telescope, and replaces the third computational hologram with the fourth computational hologram. The outgoing light from the interferometer is diffracted by the fourth computational hologram and transmitted through the zoom lens, and is perpendicularly incident on the off-axis sub-mirror of the second telescope. Then the light is reflected along the original optical path and returns to the interferometer. The wavefront W5 of the second detection optical path of the off-axis sub-mirror of the second telescope is measured (processed and calculated by the interferometer software, and the measurement method is the same as the measurement method of W1 above).

[0013] Step 6: Calculate the surface shape of the second telescope away from the axion mirror, i.e., W6 = W5 - W4;

[0014] Step 7: Replace the telescope primary mirror splicing sub-mirror and repeat steps 4 to 6 above to obtain the surface shape information of different telescope primary mirror splicing sub-mirrors.

[0015] Furthermore, the detection method shortens the detection optical path length of the off-axis sub-mirrors of different telescope primary mirrors by using the same zoom lens, and removes the influence of the transmission wavefront error of the zoom lens on the measured surface shape of the mirror under test by using the corresponding calibration optical path of each telescope. Furthermore, the method is applicable to spliced ​​sub-mirrors of primary mirrors from different telescopes, wherein the primary mirrors of different telescopes have different radii of curvature and quadratic coefficients, the off-axis distance of the spliced ​​sub-mirrors is different, and the aperture of the sub-mirrors is less than or equal to the aperture of the zoom lens.

[0016] Furthermore, the vertices of the splicing sub-mirrors of different telescopes have different radii of curvature, aspherical coefficients, and off-axis values. However, using a lens with selected parameters, the test point position is determined by performing conjugate calculations on the detection optical path for different test objects. The residual wave aberration of the detection optical path is compensated by the calculated holographic compensation.

[0017] Furthermore, for a specific splicing telescope, a dedicated standard spherical mirror is selected to calibrate the conjugate optical path error of the lens. The conjugate point position residual is corrected by a dedicated computational hologram. The radius of curvature of the standard spherical mirror is the same as the radius of curvature of the primary mirror of the specific telescope.

[0018] Furthermore, for the detection of different off-axis sub-mirrors of a specific telescope, a compensation calculation hologram is made according to the residual wave aberration of the sub-mirror detection optical path, replacing the special hologram for the above-mentioned calibration optical path. The geometric dimensions of the hologram are the same as the carrier frequency.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] This invention is based on the original refraction and diffraction combination compensation method. By setting a specific telescope-specific correction mirror and a specific telescope-specific null-position holographic element, the detection optical path is zero-position calibrated. Similar to changing the standard lens in a regular interferometer, the zero-position calibration is applicable to sub-mirrors of telescopes with different parameters, making it a universal detection method. This detection method is characterized by its simple structure and high versatility. It can be applied to the surface shape detection of sub-mirrors spliced ​​from the primary mirror of various large astronomical telescopes, effectively avoiding the cumbersome customization of surface shape detection equipment for different telescope sub-mirrors, reducing the processing and manufacturing costs of sub-mirrors with different parameters, and providing theoretical and technical support for the diversified design of large astronomical telescopes. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of splicing sub-mirrors with primary mirrors of telescopes of different apertures;

[0022] Figure 2 This is a schematic diagram of the calibration optical path for a universal surface shape detection device for splicing sub-mirrors of different telescope primary mirrors;

[0023] Figure 3 It is a calibration optical path dot plot, and the geometric radius of the dot plot is close to 0 μm;

[0024] Figure 4 It is a calibration optical path wave aberration diagram, with the root mean square value of the wave aberration close to 0 wavelengths;

[0025] Figure 5 This is a diagram illustrating stray diffraction rays in the calibrated optical path. The closest stray diffraction order ray is 0.9 mm away from the working diffraction order ray.

[0026] Figure 6 This is a side view of the working diffraction ray and stray diffraction ray of the calibration optical path;

[0027] Figure 7 This is a schematic diagram of the optical path for detecting the off-axis mirror of a specific type of telescope.

[0028] In the diagram, the markings are as follows: 1 is an interferometer, 2 is a dedicated CGH for calibrating the optical path, 3 is a focal-reduction lens, 4 is a calibration standard mirror for calibrating the optical path of a specific type of telescope sub-mirror testing equipment, 5 is a calibration standard mirror for another telescope sub-mirror testing equipment, 6 is a calibration CGH for another telescope optical path, 7 is a splicing sub-mirror of the telescope primary mirror, and 8 is the corresponding CGH for testing the optical path of the splicing sub-mirror of the telescope primary mirror. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings.

[0030] The primary mirrors and off-axis sub-mirrors of different telescopes are all 1.44-meter regular hexagonal mirrors, differing only in vertex radius of curvature, quadratic coefficient, and off-axis amount. Using a lens with selected parameters, conjugate calculations are performed on the detection optical path for different objects to determine the test point location. The residual wave aberration of the detection optical path is compensated by computational holographic compensation. To reduce the impact of the transmission wavefront error of the focal-reduction lens on the detection optical path, such as... Figure 1 As shown, when inspecting the spliced ​​sub-mirrors of different telescopes, a corresponding calibration optical path is designed for the off-axis sub-mirror inspection optical path of the telescope. The ray tracing is performed point-to-point to calculate the difference, and the transmission wavefront error introduced by the processing of the focal-reduction lens is corrected.

[0031] Based on the above ideas, this invention proposes a general surface shape detection method for splicing sub-mirrors of different telescope primary mirrors based on the principle of diffraction-refraction combination compensation detection.

[0032] This method shortens the optical path length for detecting off-axis sub-mirrors of different telescopes using a single focal-reduction lens. It then eliminates the influence of the focal-reduction lens's transmission wavefront error on the measured surface shape of the mirror under test by using the corresponding calibration optical path for each telescope. By employing a single focal-reduction lens to shorten the detection optical path length and setting up a dedicated calibration mirror (a spherical mirror) and a dedicated null-position holographic element for a specific telescope, the detection optical path is zero-position calibrated. Similar to changing the standard lens in a conventional interferometer, the zero-position calibrated optical path can be used to inspect the surface shape of sub-mirrors of telescopes with different parameters, making it a universal detection method.

[0033] For calculating the optical parameters of a zoom lens in the optical path for detecting the surface shape of a certain telescope sub-mirror, when the zoom lens is used for detecting the surface shape of other telescope primary mirror splicing sub-mirrors, it will introduce additional defocus and spherical aberration, which is compensated by CGH. However, the transmission wavefront error introduced by the surface shape processing during the development of the zoom lens cannot be ignored. Therefore, a special calibration optical path needs to be designed to calibrate and remove this error.

[0034] For a specific splicing telescope, a dedicated standard spherical mirror is selected to calibrate the lens conjugate optical path error. The conjugate point position residual is corrected by a dedicated computational hologram. The calibration mirror is a spherical mirror with the same radius of curvature as the primary mirror of the specific telescope. For the detection of different off-axis sub-mirrors of the specific telescope, a compensation computational hologram is made according to the residual wave aberration of the sub-mirror detection optical path, replacing the dedicated hologram for the calibration optical path. The geometric dimensions of the hologram are the same as the carrier frequency.

[0035] The detection system described in this patent includes: a phase-shifting interferometer, a computational hologram, a reduced-focus single lens, calibration standard mirrors for different telescopes, and an off-axis aspherical sub-mirror.

[0036] The present invention provides a universal surface shape detection method for splicing sub-mirrors of different telescope primary mirrors, comprising the following steps:

[0037] Step 1: Build the primary mirror of telescope 1, splice sub-mirrors, calibrate the optical path, and use an interferometer to acquire and process images to obtain the transmission wavefront error W1 of the corresponding focal-reduction lens of the off-axis sub-mirror;

[0038] Step 2: Replace the off-axis sub-mirror of the primary mirror of telescope 1, calculate the hologram, and use the interferometer to acquire and process the image to obtain the wavefront W2 of the off-axis sub-mirror detection optical path;

[0039] Step 3: The axion mirror shape of telescope 1, W3 = W2 - W1;

[0040] Step 4: For the surface shape detection of the telescope 2 sub-mirror, at the calibration standard mirror position, replace the corresponding calibration standard mirror of telescope 2, build the calibration optical path of the telescope 2 main mirror splicing sub-mirror, and measure and obtain the transmission wavefront error W4 of the corresponding focal reduction lens of the off-axis sub-mirror of telescope 2.

[0041] Step 5: Replace the computed hologram and measure the off-axis sub-mirror of telescope 2 to detect the wavefront W5 of the optical path;

[0042] Step 6: The axion mirror shape of telescope 2, W6 = W5 - W4;

[0043] Repeat steps 4 to 6 to obtain the surface shape information of the spliced ​​sub-mirrors of different telescope primary mirrors.

[0044] The following description, in conjunction with the high-precision surface shape detection of the splicing sub-mirrors of two large astronomical telescopes, illustrates this invention patent.

[0045] The US 30-meter telescope and the planned 12-meter optical-infrared telescope in China have optical parameters as follows:

[0046] As shown in Table 1:

[0047]

[0048] Both large astronomical telescopes' primary mirrors are assembled from hexagonal sub-mirrors, each with a diagonal diameter of 1.44 meters. The radii of curvature of the primary mirrors are 60 meters and 38.4 meters, respectively. The expression for the sagitta of the primary mirror is:

[0049]

[0050] In the formula, r 2 =x 2 +y 2 c is the curvature of the mother mirror, and K is the coefficient of the quadratic term of the mother mirror.

[0051] The optical path for surface shape detection and error calibration of the off-axion mirror in the TMT telescope is as follows: Figure 7 , Figure 2 As shown, by Figure 3-4 It can be seen that the detection optical path point diagram and wavelet aberration are close to zero, and the separation of stray diffracted rays is as follows: Figure 5-6 As shown. The assembly and adjustment steps for the optical path of the off-axis mirror shape detection are as follows:

[0052] 1. According to Figure 2 As shown, the calibration optical path for the TMT primary mirror and splicing sub-mirrors is constructed. The light emitted from interferometer 1 is diffracted by CGH 2, transmitted through zoom lens 3, and perpendicularly incident on standard spherical mirror 4. The light is reflected along the original optical path and returns to the interferometer. The test wavefront interferes with the reference wavefront inside the interferometer, forming interference fringes. The fringes are acquired by a CCD and processed by a computer to obtain the transmission wavefront error W of the zoom lens in the calibration optical path. 1-0 The transmission wavefront of the calibration optical path is transformed by ray tracing to obtain the transmission wavefront W1 of the corresponding region of the off-axis sub-mirror detection optical path.

[0053] 2. Press Figure 7 As shown, the detection optical path of the TMT main mirror splicing sub-mirror is constructed. The light emitted from the interferometer 1 is diffracted by CGH 8 and transmitted through the zoom lens 3. It is then incident perpendicularly on the off-axis sub-mirror 7 of the TMT main mirror. The light is reflected along the original optical path and returns to the interferometer. The wavefront W2 of the off-axis sub-mirror detection optical path is measured.

[0054] 3. Calculate the shape W3 of the TMT primary mirror splicing sub-mirror, W3 = W2 - W1.

[0055] For the surface shape detection of the off-axis mirror of the LOT telescope, the optical path assembly and adjustment steps are as follows:

[0056] 1. For example Figure 2 As shown, at the position of the TMT calibration standard spherical mirror 4 (TMT off-axis sub-mirror 7), the LOT sub-mirror detection optical path dedicated calibration mirror 5 is replaced, and the LOT main mirror splicing sub-mirror calibration optical path is built. The light emitted from the interferometer 1 is diffracted by CGH 6, transmitted through the zoom lens 3, and perpendicularly incident on the standard spherical mirror 5. The light is reflected along the original optical path and returns to the interferometer. The test wavefront interferes with the reference wavefront inside the interferometer, forming interference fringes. After the fringe is acquired by the CCD and processed by the computer, the transmission wavefront error W of the zoom lens in the calibration optical path is obtained. 4-0 The transmission wavefront of the calibration optical path is transformed by ray tracing to obtain the transmission wavefront W4 of the corresponding region of the off-axis sub-mirror detection optical path.

[0057] 2. Press Figure 7 As shown, the detection optical path of the LOT main mirror splicing sub-mirror is constructed. The light emitted from the interferometer 1 is diffracted by CGH and transmitted through the zoom lens 3. It is then incident perpendicularly on the off-axis sub-mirror of the LOT main mirror. The light is reflected along the original optical path and returns to the interferometer. The wavefront W5 of the off-axis sub-mirror detection optical path is measured.

[0058] 3. Calculate the surface shape W6 of the TMT primary mirror splicing sub-mirror, where W6 = W5 - W4.

[0059] As mentioned above, for the detection of the surface shape of off-axis sub-mirrors of different telescopes, it is only necessary to calibrate the transmission wavefront of the corresponding area of ​​the focal reduction mirror in the detection optical path, and remove this part of the transmission wavefront error as the system error of the off-axis sub-mirror detection optical path to obtain the actual surface shape of the off-axis sub-mirror.

[0060] This invention provides a universal surface shape detection method for spliced ​​sub-mirrors of different telescope primary mirrors. The method uses a single reduced-focus lens with selected parameters to shorten the optical path length for detecting off-axis sub-mirrors of different telescopes. Residual wavefront aberrations at the test points of each sub-mirror's optical path are compensated by computational holographic compensation. When detecting spliced ​​sub-mirrors of different telescopes, a corresponding calibration optical path is designed, and a dedicated standard spherical mirror is selected to calibrate the transmission wavefront error introduced by the processing of the reduced-focus lens. Ray tracing is used to obtain the transmission wavefront of the corresponding region of the mirror under test and the reduced-focus lens. Point-to-point subtraction is performed to calculate the surface shape information of the off-axis sub-mirror of the telescope. This invention features high precision and strong versatility, enabling batch and rapid detection of off-axis sub-mirrors of different telescope primary mirrors.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A universal surface shape detection method for splicing sub-mirrors of different telescope primary mirrors, characterized in that: Includes the following steps: Step 1: Construct the first calibration optical path for the first telescope primary mirror splicing sub-mirror. The first calibration optical path includes an interferometer, a first computational hologram, a zoom lens, and a first standard mirror corresponding to the first telescope. The outgoing light from the interferometer is diffracted by the first computational hologram and transmitted through the zoom lens, then incident perpendicularly to the first standard mirror. Afterward, the light is reflected along the original optical path and returns to the interferometer. The wavefront of the returning light interferes with the reference wavefront inside the interferometer, forming interference fringes. The transmission wavefront error W of the zoom lens in the first calibration optical path is obtained by processing the data with the interferometer software. 1-0 The transmission wavefront of the first calibration optical path is transformed by ray tracing to obtain the transmission wavefront W1 of the corresponding region of the first calibration optical path of the off-axle mirror of the first telescope. Step 2: Construct the first detection optical path of the first telescope primary mirror splicing sub-mirror. The first detection optical path replaces the first standard mirror in the first calibration optical path with the first telescope off-axis sub-mirror and replaces the first computational hologram with the second computational hologram. The outgoing light from the interferometer is diffracted by the second computational hologram and transmitted through the zoom lens, and is perpendicularly incident on the first telescope off-axis sub-mirror. Then the light is reflected along the original optical path and returns to the interferometer. The wavefront W2 of the first detection optical path of the first telescope off-axis sub-mirror is measured. Step 3: Calculate the surface shape of the first telescope away from the axion mirror, i.e., W3 = W2 - W1; Step 4: Construct the second calibration optical path for the second telescope's primary mirror splicing sub-mirror. Replace the off-axis sub-mirror of the first telescope with the corresponding second standard mirror of the second telescope at the position of the first standard mirror, and replace the second computational hologram with the third computational hologram. The outgoing light from the interferometer is diffracted by the third computational hologram and transmitted through a focal-reduction lens, then incident perpendicularly to the second standard mirror. Afterward, the light is reflected along the original optical path and returns to the interferometer. The wavefront of the returning light interferes with the reference wavefront inside the interferometer, forming interference fringes. After processing, the transmission wavefront error W of the focal-reduction lens in the second calibration optical path is obtained. 4-0 The transmission wavefront of the second calibration optical path is transformed by using ray tracing to obtain the transmission wavefront W4 of the corresponding region of the second calibration optical path of the off-axle mirror of the second telescope. Step 5: Construct the second detection optical path of the second telescope primary mirror splicing sub-mirror. The second detection optical path replaces the second standard mirror in the second calibration optical path with the off-axis sub-mirror of the second telescope, and replaces the third computational hologram with the fourth computational hologram. The outgoing light from the interferometer is diffracted by the fourth computational hologram and transmitted through the zoom lens, and is perpendicularly incident on the off-axis sub-mirror of the second telescope. Then the light is reflected along the original optical path and returns to the interferometer. The wavefront W5 of the second detection optical path of the off-axis sub-mirror of the second telescope is measured. Step 6: Calculate the surface shape of the second telescope away from the axion mirror, i.e., W6 = W5 - W4; Step 7: Replace the telescope primary mirror splicing sub-mirror and repeat steps 4 to 6 above to obtain the surface shape information of different telescope primary mirror splicing sub-mirrors.

2. The universal surface shape detection method for splicing sub-mirrors of different telescope primary mirrors according to claim 1, characterized in that, The detection method shortens the optical path length of the off-axis sub-mirrors of different telescopes by using the same zoom lens, and removes the influence of the transmission wavefront error of the zoom lens on the measured surface shape of the mirror under test by using the corresponding calibration optical path of each telescope.

3. The universal surface shape detection method for splicing sub-mirrors of different telescope primary mirrors according to claim 1, characterized in that, The method is designed for splicing sub-mirrors from primary mirrors of different telescopes. The primary mirrors of different telescopes have different radii of curvature and quadratic coefficients, and the splicing sub-mirrors have different off-axis values. The aperture of the sub-mirrors is less than or equal to the aperture of the zoom lens.

4. The universal surface shape detection method for splicing sub-mirrors of different telescope primary mirrors according to claim 1, characterized in that, Different telescopes have different vertices of curvature radius, aspherical coefficient and off-axis amount of splicing sub-mirrors, but using a lens with selected parameters, the test point position is determined by conjugate calculation of the detection optical path for different test objects, and the residual wave aberration of the detection optical path is compensated by calculation of holographic compensation.

5. The universal surface shape detection method for splicing sub-mirrors of different telescope primary mirrors according to claim 1, characterized in that, For a specific splicing telescope, a dedicated standard spherical mirror is selected to calibrate the conjugate optical path error of the lens. The conjugate point position residual is corrected by a dedicated computational hologram. The radius of curvature of the standard spherical mirror is the same as the radius of curvature of the primary mirror of the specific telescope.

6. The universal surface shape detection method for splicing sub-mirrors of different telescope primary mirrors according to claim 1, characterized in that, For different off-axis sub-mirrors of a specific telescope, a compensation calculation hologram is made according to the residual wave aberration of the sub-mirror detection optical path, replacing the special hologram for the calibration optical path mentioned above. The geometric dimensions of the hologram are the same as the carrier frequency.

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