Progressive generation method for large-aperture spliced telescope

Abstract

The invention relates to the technical field of large-aperture telescope construction, in particular to a large-aperture spliced telescope progressive generation method, which comprises the following steps of S1, constructing a local co-phase region at the edge of a large-aperture telescope by using spliced sub-mirrors through assistance of a small-aperture secondary mirror, and forming local co-phase imaging capability; s2, the step S1 is repeated, and equal-area local co-phase regions are constructed at the symmetrical positions of the edge of the large-aperture telescope; s3, constructing an interference imaging system through optical path difference adjustment, zero interference elimination and two symmetrical local co-phase regions; s4, repeating the steps S1 to S3, constructing more symmetrical and equal-area local co-phase regions at the edge of the large-aperture telescope, and constructing interference imaging in which the plurality of symmetrical local co-phase regions participate; and S5, constructing local co-phase regions in sequence from the edge to the center until the construction of the whole large-aperture telescope is completed.

Description

Technical Field

[0001] The invention relates to the technical field of large telescope construction, and in particular to a method for progressively generating a large-aperture spliced ​​telescope. Background Art

[0002] As human beings’ demand for obtaining information about space and the outside world continues to increase, the demand for telescope apertures continues to increase in order to obtain larger light-collecting areas and resolution capabilities. Limited by the manufacturing cost, process and transportation of large-aperture single mirrors, telescopes with spliced ​​primary mirrors have gradually developed. In the late 1970s, there was a boom in building 10-meter-class telescopes abroad. Subsequently, at the end of the 20th century, telescopes with spliced ​​primary mirrors such as the KECK Telescope, the Hobby-Eberly Telescope (HET), the Southern African Large Telescope (SALT), and the Gran Telescope (GTC) were built one after another. In 2008, the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) was completed and accepted, indicating that China has also mastered the relevant research and development technology of spliced ​​primary mirror telescopes.

[0003] Long baseline interferometry is another important technical route to improve the resolution of telescopes. By prioritizing the improvement of the detection capabilities of some important spatial frequency domains and combining them with time-sharing multiplexing methods, it can ultimately achieve the approximate equivalence of large-aperture mirrors.

[0004] At present, large-aperture spliced ​​telescopes have the characteristics of high construction cost and long construction period, and cannot meet the demand for rapid generation of detection and imaging capabilities of large-aperture telescopes. Summary of the invention

[0005] The present invention provides a progressive generation method for a large-aperture spliced ​​telescope to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions: A method for progressively generating a large-aperture spliced ​​telescope comprises the following steps: S1: With the assistance of a small-aperture secondary mirror, a local common phase region is constructed at the edge of a large-aperture telescope using spliced ​​sub-mirrors to form a local common phase imaging capability; S2: Repeat step S1 to construct local common phase regions of equal area at symmetrical positions on the edge of the large aperture telescope; S3: Through optical path difference adjustment and zero interference elimination, two symmetrical local common phase regions construct an interference imaging system; S4: repeating steps S1-S3, constructing more symmetrical local common phase regions of equal area at the edge of the large aperture telescope, and constructing interferometric imaging involving multiple symmetrical local common phase regions; S5: Construct local common phase regions in sequence from the edge to the center until the construction of the entire large-aperture telescope is completed.

[0007] Preferably, the total area of ​​the local common phase region is equivalent to a circle with a diameter of five meters.

[0008] Preferably, step S2 specifically includes: In each local common phase region, channel spectroscopy and broadband method are used to perform common phase control; Preferably, step S3 specifically includes: S31, using a secondary mirror to control the focus position between the light paths of the two local common phase regions, and then using a back-end delay line to control the optical path difference of the light paths of the two local common phase regions; S32. In terms of fringe tracking, the channel spectrum method is used to adjust the group delay by using the optical path difference of different spectral bands; S33. With respect to phase delay, a local scanning method is used to determine the specific common phase position by fitting a sine curve.

[0009] Preferably, the progressive generation method of a large-aperture spliced ​​telescope further includes: Zero interference in a wide spectrum: A prism is used to disperse a local wide spectrum light. After being dispersed by the prism, it enters the segmented deformable mirror after reflection. The segmented deformable mirror is used to delay the optical path of different spectrum bands. After that, the light beams are combined.

[0010] Preferably, the progressive generation method of a large-aperture spliced ​​telescope further includes: Utilizing the idea of ​​aperture coding method, pupil interferometry is used between single local common phase regions to realize long baseline interference in the central area. On this basis, sub-mirrors participating in the interference are added one by one. Based on the hybrid interference pattern, the position of the sub-mirror is determined by the interference fringes.

[0011] Preferably, the mixed interference mode comprises: Fizeau interferometry is used in each local common phase region, and Michelson interferometry is used in the beam synthesis process.

[0012] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a progressive generation method for a large-aperture spliced ​​telescope, which utilizes the interference imaging system of the local common phase region of the large-aperture telescope and effectively shortens the capacity generation time of the large-aperture telescope through the idea of ​​"building and using at the same time". At the same time, a hybrid interference mode assembly and adjustment method is adopted to effectively improve the sub-mirror assembly and adjustment efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A schematic flow chart of a progressive generation method of a large-aperture spliced ​​telescope provided by an embodiment of the present invention; Figure 2 A schematic diagram of wide-band zeroing interference in a progressive generation method for a large-aperture spliced ​​telescope provided by an embodiment of the present invention; Figure 3 A schematic diagram of a mixed interference pattern in a progressive generation method for a large-aperture spliced ​​telescope provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0014] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] Figure 1 A flowchart of a progressive generation method for a large-aperture spliced ​​telescope provided by an embodiment of the present invention. Figure 1 As shown, in one embodiment of the present invention, the embodiment of the present invention provides a progressive generation method for a large-aperture spliced ​​telescope, comprising the following steps: S1: With the assistance of a small-aperture secondary mirror, a local common phase region is constructed at the edge of a large-aperture telescope using spliced ​​sub-mirrors to form a local common phase imaging capability; S2: Repeat step S1 to construct local common phase regions of equal area at symmetrical positions on the edge of the large aperture telescope; S3: Through optical path difference adjustment and zero interference elimination, two symmetrical local common phase regions construct an interference imaging system; S4: repeating steps S1-S3, constructing more symmetrical local common phase regions of equal area at the edge of the large aperture telescope, and constructing interferometric imaging involving multiple symmetrical local common phase regions; S5: Construct local common phase regions in sequence from the edge to the center until the construction of the entire large-aperture telescope is completed.

[0016] Specifically, in one embodiment of the present invention, the total area of ​​the local common phase region is equivalent to a circle with a diameter of five meters.

[0017] In one embodiment of the present invention, step S2 specifically includes: In each local common phase region, channel spectroscopy and broadband method are used to perform common phase control; Step S3 specifically includes: S31, using a secondary mirror to control the focus position between the light paths of the two local common phase regions, and then using a back-end delay line to control the optical path difference of the light paths of the two local common phase regions; S32. In terms of fringe tracking, the channel spectrum method is used to adjust the group delay by using the optical path difference of different spectral bands; S33. With respect to phase delay, a local scanning method is used to determine the specific common phase position by fitting a sine curve.

[0018] Figure 2 A schematic diagram of wide-band zeroing interference in a progressive generation method for a large-aperture spliced ​​telescope provided by an embodiment of the present invention. Figure 2 As shown, in one embodiment of the present invention, the progressive generation method of a large-aperture spliced ​​telescope further includes: Zero interference in a wide spectrum: A prism is used to disperse a local wide spectrum light. After being dispersed by the prism, it enters the segmented deformable mirror after reflection. The segmented deformable mirror is used to delay the optical path of different spectrum bands. After that, the light beams are combined.

[0019] Furthermore, in one embodiment of the present invention, the progressive generation method of a large aperture spliced ​​telescope further includes: Utilizing the idea of ​​aperture coding method, pupil interferometry is used between single local common phase regions to realize long baseline interference in the central area. On this basis, sub-mirrors participating in the interference are added one by one. Based on the hybrid interference pattern, the position of the sub-mirror is determined by the interference fringes.

[0020] Figure 3 A schematic diagram of a mixed interference pattern in a progressive generation method for a large-aperture spliced ​​telescope provided by an embodiment of the present invention. Figure 3 As shown, in one embodiment of the present invention, the mixed interference mode includes: Fizeau interferometry is used in each region, and Michelson interferometry is used in the beam synthesis process.

[0021] Working principle: The workflow of this method includes: common phase adjustment of local common phase areas, construction of local common phase areas in symmetrical positions based on the constructed local common phase areas, construction of interference imaging system with two symmetrical local common phase areas, interference imaging system involving multiple common phase areas, and gradual improvement of local common phase areas.

[0022] In the common phase adjustment step of the local common phase area, first, through the cooperation of the small-aperture secondary mirror, the focus of multiple spliced ​​sub-mirrors is adjusted to converge at one place, and then the phase error in a large range is determined by the broadband method. Next, based on the channel spectroscopy method, the wide spectrum light is dispersed into multiple narrowband spectral channels using devices such as gratings or Fabry-Perot interferometers, and the phase error value with higher precision is detected. The phase error information obtained by the broadband method and the channel spectroscopy method is fed back to the sub-mirror attitude control unit to complete the common phase adjustment of multiple sub-mirrors.

[0023] In the step of constructing a local common phase region at a symmetrical position based on the constructed local common phase region, assuming that a certain sub-mirror in the constructed local common phase region is A, and the spliced ​​sub-mirror symmetrical to the position of A on the large-aperture spliced ​​mirror is A', Michael interference between the spliced ​​sub-mirrors A and A' is constructed, and the position of the spliced ​​sub-mirror A' is adjusted according to the shape of the interference fringes based on the position of the spliced ​​sub-mirror A' until the spliced ​​sub-mirror A' is at a suitable position. Repeat the steps to adjust the positions of other spliced ​​sub-mirrors until the construction of the local common phase region at a symmetrical position is completed.

[0024] The steps of constructing an interference imaging system in two symmetrical local common phase regions are as follows: first, a secondary mirror is used to assist in adjusting the focal points of the two optical paths to converge at one point; then, a prism is introduced into one of the optical paths to disperse the wide-spectrum light; a segmented deformable mirror is used to perform half-wavelength optical path difference delay control on the light of different spectral bands; at the output end of the optical path, a prism is used again to combine the multi-spectral light after delay control; then, a local scanning method is used to determine the specific common phase position by fitting the sine curve, and the two common phase regions are adjusted to achieve interference imaging.

[0025] In the interferometric imaging system involving multiple common phase regions, first construct two symmetrical common phase regions, then construct an interferometric imaging system for the two common phase regions, and finally adjust and merge the newly constructed interference with the previously constructed interference to construct an interferometric imaging system with more complete spectral information. Construct pairs of common phase regions in order from the edge to the center, and merge the newly constructed interference with the interference involving multiple common phase regions in the previous stage until the construction of the entire large-aperture spliced ​​telescope is completed.

[0026] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A progressive generation method for a large-aperture spliced ​​telescope, characterized in that: The following steps are involved: S1: With the assistance of a small-aperture secondary mirror, a local common phase region is constructed at the edge of a large-aperture telescope using spliced ​​sub-mirrors to form a local common phase imaging capability; S2: Repeat step S1 to construct local common phase regions of equal area at symmetrical positions on the edge of the large aperture telescope; S3: Through optical path difference adjustment and zero interference elimination, two symmetrical local common phase regions construct an interference imaging system; S4: repeating steps S1-S3, constructing more symmetrical local common phase regions of equal area at the edge of the large aperture telescope, and constructing interferometric imaging involving multiple symmetrical local common phase regions; S5: Construct local common phase regions in sequence from the edge to the center until the construction of the entire large-aperture telescope is completed.

2. The progressive generation method of a large aperture spliced ​​telescope according to claim 1, characterized in that: The total area of ​​the local common phase region is equivalent to a circle with a diameter of five meters.

3. The progressive generation method of a large aperture spliced ​​telescope according to claim 1, characterized in that: Step S2 specifically includes: Channel spectroscopy and broadband method are used to perform common phase regulation in each local common phase region.

4. The progressive generation method of a large aperture spliced ​​telescope according to claim 1, characterized in that: Step S3 specifically includes: S31, using a secondary mirror to control the focus position between the light paths of the two local common phase regions, and then using a back-end delay line to control the optical path difference of the light paths of the two local common phase regions; S32. In terms of fringe tracking, the channel spectrum method is used to adjust the group delay by using the optical path difference of different spectral bands; S33. With respect to phase delay, a local scanning method is used to determine the specific common phase position by fitting a sine curve.

5. The progressive generation method of a large aperture spliced ​​telescope according to claim 1, characterized in that: The progressive generation method of the large-aperture spliced ​​telescope also includes: Zero interference in a wide spectrum: A prism is used to disperse a local wide spectrum light. After being dispersed by the prism, it enters the segmented deformable mirror after reflection. The segmented deformable mirror is used to delay the optical path of different spectrum bands. After that, the light beams are combined.

6. The progressive generation method of a large aperture spliced ​​telescope according to claim 1, characterized in that: The progressive generation method of the large-aperture spliced ​​telescope also includes: Utilizing the idea of ​​aperture coding method, pupil interferometry is used between single local common phase regions to realize long baseline interference in the central area. On this basis, sub-mirrors participating in the interference are added one by one. Based on the hybrid interference pattern, the position of the sub-mirror is determined by the interference fringes.

7. The progressive generation method of a large aperture spliced ​​telescope according to claim 6, characterized in that: The hybrid interference mode includes: Fizeau interferometry is used in each local common phase region, and Michelson interferometry is used in the beam synthesis process.

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