Alignment adjustment method between telescope onboard adaptive optics terminal and main optical system

Abstract

The present invention relates to a method for aligning and adjusting an onboard adaptive optics terminal of a telescope with a primary optical system, comprising the following steps: installing a laser calibration light source at the center of a secondary mirror, installing an adaptive optics terminal, and adjusting a pickup assembly so that the laser calibration light source illuminates a Hartmann camera target surface; placing a small-aperture collimator at the center of the secondary mirror at appropriate times, and repeatedly using the telescope to observe and image natural stars or the small-aperture collimator until the natural star image is located at the center of the Hartmann camera subaperture. The method for aligning and adjusting the onboard adaptive optics terminal of a telescope with a primary optical system of the present invention utilizes a method combining laser axis penetration with relative misalignment error compensation to quickly and safely complete the docking of the onboard adaptive optics system with the primary system.

Description

Technical Field

[0001] The present invention relates to the technical field of telescope imaging quality, and in particular to a method for aligning and adjusting an onboard adaptive optical terminal of a telescope and a main optical system. Background Art

[0002] To overcome the effects of atmospheric turbulence on telescope imaging quality, adaptive optics technology based on deformable mirrors has been invented. Its core components include a Hartmann imaging assembly and a deformable mirror. These components are located in the pupil behind the primary mirror, with the deformable mirror serving as the primary mirror's exit pupil, and the three components achieving pupil matching. During observation, the Hartmann imaging assembly calculates the target's center of mass at each subaperture and the overall tilt. Simultaneously, a wavefront processor calculates instantaneous wavefront information through fitting, controlling and driving the deformable mirror to correct wavefront distortion in real time, overcoming high-order wavefront aberrations introduced by atmospheric turbulence. As the core component of an adaptive optics system, the Hartmann imaging assembly has the characteristics of a small field of view, high precision, and a narrow dynamic range. Therefore, how to quickly, safely, and accurately align the adaptive optics terminal with the primary optical system has always been a challenge.

[0003] Existing adaptive optics systems are mainly divided into off-board systems and on-board systems according to their placement. There are many methods for aligning and adjusting the adaptive optics terminal with the telescope. For the off-board system, the adaptive optics system is located in the kude room and does not move with the rotation of the telescope. It can adjust the stars in real time, which is very convenient; however, for the on-board system, the adaptive system rotates with the telescope in real time. During star alignment, the telescope is always powered on. There is a risk of overshoot when researchers adjust the telescope, which is dangerous. At the same time, since the telescope has a certain pitch angle, it is not conducive to operation when adjusting the stars. Summary of the Invention

[0004] The present invention aims to solve the technical problems in the prior art and provides a method for aligning and adjusting an onboard adaptive optical terminal of a telescope and a main optical system.

[0005] In order to solve the above technical problems, the technical solutions of the present invention are as follows:

[0006] A method for aligning and adjusting an onboard adaptive optical terminal of a telescope with a main optical system, wherein the system to which the method is applicable includes:

[0007] a telescope having a secondary mirror;

[0008] A laser calibration light source, which is used to emit laser light as a calibration light source;

[0009] A small-aperture collimator, which is used as an imaging light source;

[0010] An adaptive optics terminal, which includes a Hartmann camera and a pickup assembly;

[0011] The alignment adjustment method comprises the following steps:

[0012] Step i: Install a laser calibration light source at the center of the secondary mirror, install an adaptive optics terminal, and adjust the Pick-up component so that the laser calibration light source illuminates the target surface of the Hartmann camera;

[0013] Step ii: placing the small-aperture collimator at the center of the secondary mirror at the appropriate time, and repeatedly using the telescope to observe and image natural stars or the small-aperture collimator until the natural star image is located at the center of the Hartmann camera subaperture.

[0014] In the above technical solution, step i specifically includes the following steps:

[0015] Install a laser calibration light source at the center of the secondary mirror, and adjust the posture of the laser calibration light source so that its laser emission direction coincides with the main optical axis;

[0016] According to the position of the light spot, adjust the Pick-up component inside the adaptive optics terminal until the light spot appears near the center of the target surface of the Hartmann camera and forms an image.

[0017] In the above technical solution, step ii specifically includes the following steps:

[0018] Step 1: Replace the laser calibration light source with a small-aperture collimator and image it with a Hartmann camera;

[0019] Step 2: Use a telescope to image the natural star, adjust the telescope's direction, record the image position of the natural star in the Hartmann camera, and calculate its offset Δ and tilt θ;

[0020] Step 3: Open the small-aperture collimator, use the Hartmann camera to image the small-aperture collimator, and record the imaging position of the small-aperture collimator;

[0021] Step 4: Use the Pick-up component to adjust the imaging position of the small-aperture collimator by an offset of -Δ and a tilt of -θ. After the adjustment is completed, use the telescope to observe natural stars again. Repeat this process of using the telescope to observe and image natural stars and the small-aperture collimator until the offset Δ and the tilt θ approach 0.

[0022] In the above technical solution, the Pick-up component includes: two reflectors with an angle of 90°, which can realize a 90° deflection of the light path.

[0023] The present invention has the following beneficial effects:

[0024] The method for aligning and adjusting the onboard adaptive optical terminal of a telescope and the main optical system of the present invention adopts a method combining laser axis penetration and relative misalignment error compensation, which can quickly and safely complete the docking work of the onboard adaptive optical system and the main system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Figure 1 Schematic diagram of the telescope system.

[0027] Figure 2 This is a schematic diagram of the Pick-up component.

[0028] Figure 3 The figure is a general flow chart of the alignment adjustment method of the onboard adaptive optics terminal of a telescope and the main optical system of the present invention.

[0029] Figure 4 Schematic diagram for fine-tuning the alignment of the onboard adaptive optics terminal and the telescope's main optical system.

[0030] The reference numerals in the figures indicate:

[0031] 1-Secondary mirror; 2-Laser calibration light source; 3-Adaptive optics terminal; 4-Pick-up assembly; 5-Hartmann camera; 6-Small aperture collimator. DETAILED DESCRIPTION

[0032] The inventive concept of the present invention is: the present invention adopts a method combining laser axis penetration and relative misalignment error compensation to quickly and safely complete the docking work between the on-board adaptive optical system and the main system.

[0033] The specific workflow is as follows:

[0034] First, a laser calibration light source is installed at the center of the secondary mirror, with the laser beam representing the actual optical axis of the telescope. Next, the adaptive optics terminal is installed. By adjusting the pickup assembly inside the platform, the laser calibration light source is directed onto the Hartmann camera target, achieving coarse alignment between the adaptive optics terminal and the telescope.

[0035] Secondly, the laser calibration light source is replaced with a small-aperture collimator. The light emitted by the small-aperture collimator can form an image on the target surface of the Hartmann camera and record the imaging position.

[0036] Finally, by using a telescope to observe and image a natural star, we can see the sub-aperture imaging position of the natural star in the Hartmann camera, calculate the offset Δ and tilt θ between the actual imaging position and the theoretical imaging position, image the small-aperture light tube again, adjust the Pick-up component inside the adaptive optics terminal so that its imaging position moves by offset -Δ and tilt -θ, and then observe the natural star again. Repeat this process several times until the natural star image is located at the center of the sub-aperture of the Hartmann camera, and the adaptive optics terminal is aligned with the main optical system.

[0037] The present invention will be described in detail below with reference to the accompanying drawings.

[0038] The basic contents of the present invention are described in detail as follows:

[0039] like Figure 1 The diagram shows the entire telescope system, which primarily consists of a tracking mount, a quadruple lens, a primary mirror, a secondary mirror 1, a tertiary mirror, a secondary tube, a secondary mirror ring beam, and an adaptive optics terminal 3. During observation, light is reflected along the primary mirror, secondary mirror 1, and tertiary mirror to the adaptive optics terminal 3 on the telescope's Nice platform. This terminal contains multiple imaging cameras, such as the Hartmann camera 5, which has a small field of view and high precision. However, due to installation errors, the Hartmann camera 5 cannot image the target unless it is adjusted.

[0040] The present invention mainly solves the problem of docking the adaptive optical terminal 3 with the main optical system. The method for aligning and adjusting the adaptive optical terminal on a telescope and the main optical system of the present invention includes the following steps:

[0041] First, install a laser calibration light source 2 at the center of the secondary mirror 1 to represent the optical axis of the telescope, as shown in Figure 1 As shown, the difference from the actual imaging process is that the laser calibration light source 2 does not pass through the primary mirror and the secondary mirror 1, but is directly reflected from the three mirrors into the adaptive optics terminal 3, and then the Pick-up component 4 inside the adaptive optics terminal 3 is adjusted until the Hartmann camera 5 images the laser calibration light source 2.

[0042] Secondly, the laser calibration light source 2 is replaced with a small-aperture collimator 6. The light emitted by the small-aperture collimator 6 is imaged on the target surface of the Hartmann camera 5, and the imaging position is recorded. Then, the North Star is selected as the natural star to be observed, and the natural star is observed using a telescope. The imaging position of the natural star in the Hartmann camera 5 is recorded, and its offset Δ and tilt θ are calculated. The small-aperture collimator 6 replaces the laser calibration light source 2, and the small-aperture collimator 6 is imaged again. The imaging position of the small-aperture collimator 6 is adjusted by -Δ and -θ through the Pick-up component 4. This process is repeated several times to align the adaptive optics terminal 3 with the telescope.

[0043] The Pick-up assembly 4 is composed of two reflectors with an angle of 90°, which can realize a 90° deflection of the light path. The specific structure is as follows Figure 2 As shown, it mainly includes: a first Pick-up mirror, a first Pick-up mirror adjustment screw, a second Pick-up mirror, a second Pick-up mirror adjustment screw and a lens barrel. Each reflector can adjust the x and y two-dimensional tilt. By swapping and coordinating with each other, optical path pupil matching can be achieved.

[0044] The present invention provides a method for aligning and adjusting the telescope's onboard adaptive optical terminal and the main optical system. The overall implementation process is as follows: Figure 3 As shown in the overall flow chart, it can be seen that the docking of the adaptive optics terminal and the main optical system is divided into two parts: coarse alignment and fine adjustment.

[0045] During the coarse alignment phase, a laser calibration light source 2 is installed at the center of the secondary mirror 1. The laser calibration light source 2 is adjusted so that its laser emission direction coincides with the primary optical axis. Unlike actual telescope imaging, the light emitted by the laser calibration light source 2 is not reflected by the primary and secondary mirrors 1, but is directly reflected by these three mirrors into the adaptive optics terminal 3. The adaptive optics terminal 3 is fixed to the telescope's crossbar with screws, resulting in poor positioning accuracy. At this point, the Hartmann camera 5 cannot image the laser calibration light source 2. Based on the light spot position, an approximation method is used to continuously adjust the tilt of the Pick-up assembly 4 located inside the platform until the light spot appears near the center of the Hartmann camera 5 target surface and forms an image. This completes the coarse alignment phase.

[0046] The fine adjustment phase is divided into the following four steps:

[0047] Step 1: Replace the laser calibration light source 2 with a small-aperture collimator 6 and form an image on the Hartmann camera 5;

[0048] Step 2: Use the telescope to image the North Star, adjust the telescope pointing, record the image position of the North Star in the Hartmann camera 5, and calculate its offset Δ and tilt θ, as shown in the following example: Figure 4 As shown;

[0049] Step 3: Open the small-aperture collimator 6, use the Hartmann camera 5 to image the small-aperture collimator 6, and record the imaging position of the small-aperture collimator 6;

[0050] Step 4: Use the Pick-up assembly 4 located inside the platform to adjust the imaging position of the small-aperture collimator 6 by adjusting the offset -Δ and tilt -θ. After the adjustment is completed, use the telescope to observe the North Star again. Use the approximation method and repeat this process several times to make the offset Δ and tilt θ approach 0. At this point, the precision adjustment is completed and the adaptive optics terminal 3 is docked with the telescope.

[0051] In a specific embodiment of the present invention, the terms "small-aperture collimator" and "small-aperture optical tube" are synonymous, and all refer to small-aperture collimators. The natural star used for imaging is the North Star. In other specific embodiments, other natural stars suitable for observation may be selected for telescope imaging.

[0052] The method for aligning and adjusting the onboard adaptive optical terminal of a telescope and the main optical system of the present invention adopts a method combining laser axis penetration and relative misalignment error compensation, which can quickly and safely complete the docking work of the onboard adaptive optical system and the main system.

[0053] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for aligning and adjusting an onboard adaptive optics terminal of a telescope with a main optical system, characterized in that: The alignment adjustment method is applicable to systems including: a telescope having a secondary mirror (1); A laser calibration light source (2), the laser calibration light source (2) is used to emit laser light and serve as a calibration light source; A small-aperture collimator (6), the small-aperture collimator (6) being used as an imaging light source; An adaptive optical terminal (3), wherein a Hartmann camera (5) and a pickup assembly (4) are provided in the adaptive optical terminal (3); The alignment adjustment method comprises the following steps: Step i: installing a laser calibration light source (2) at the center of the secondary mirror (1), installing an adaptive optical terminal (3), and adjusting a pickup assembly (4) so ​​that the laser calibration light source (2) irradiates the target surface of the Hartmann camera (5); comprising the following steps: A laser calibration light source (2) is installed at the center of the secondary mirror (1), and the posture of the laser calibration light source (2) is adjusted so that the laser emission direction thereof coincides with the main optical axis; According to the position of the light spot, the Pick-up component (4) inside the adaptive optical terminal (3) is adjusted until the light spot appears near the center of the target surface of the Hartmann camera (5) and forms an image; Step ii: placing the small-aperture collimator (6) at the center of the secondary mirror (1) at an appropriate time, and repeatedly using the telescope to observe and image natural stars or the small-aperture collimator (6) until the natural star image is located at the center of the sub-aperture of the Hartmann camera (5); comprising the following steps: Step 1: Replace the laser calibration light source (2) with a small-aperture collimator (6) and form an image on the Hartmann camera (5); Step 2: Use a telescope to image the natural star, adjust the telescope's direction, record the image position of the natural star in the Hartmann camera (5), and calculate its offset Δ and tilt θ; Step 3: Open the small-aperture collimator (6), use the Hartmann camera (5) to image the small-aperture collimator (6), and record the imaging position of the small-aperture collimator (6); Step 4: Adjust the imaging position of the small-aperture collimator (6) by using the Pick-up component (4), and the adjustment amount is offset -Δ and tilt -θ. After the adjustment is completed, use the telescope to observe natural stars again; repeatedly use the telescope to observe and image natural stars and the small-aperture collimator (6) until the offset Δ and tilt θ approach 0.

2. The method for aligning and adjusting the telescope onboard adaptive optics terminal and the main optical system according to claim 1, characterized in that: The Pick-up component (4) comprises two reflectors with an included angle of 90°, which can realize a 90° folding of the light path.

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