CN114594587A - Ultraviolet sky-patrol optical imaging system - Google Patents

Abstract

In the optical imaging system for ultraviolet sky surveying of the present disclosure, the primary mirror is used for receiving the incident parallel light beam and reflecting the parallel light beam to the secondary mirror; the secondary mirror is used for reflecting the parallel light beam to the prism or the imaging filter; After filtering by prismatic scattering or imaging filter, it is transmitted to the correction lens by the prismatic or imaging filter; after the correction lens corrects the aberration of the parallel beam, the parallel beam is imaged to the area array detection The parallel beam is dispersed by the prism grid, and then corrected by the correction lens, and then imaged on the area array detector to obtain the spectral image of the observation target; the parallel beam is filtered by the imaging filter and then corrected by the correction lens. The observation image of the observation target is obtained on the detector. The ultraviolet sky survey observation with a large field of view can be realized based on the combination of target imaging and spectral imaging, and has the advantages of small size, high precision and simple optical path.

Description

An Optical Imaging System for Ultraviolet Sky Survey

technical field

The invention belongs to the technical field of ultraviolet astronomical detection and detection, in particular to an optical imaging system for ultraviolet sky survey.

Background technique

Ultraviolet astronomical observation instruments are the main method to study the evolution of galaxies, and are currently the hot spot of astronomical observation research in the world. Ultraviolet spectra of celestial objects can be used to study the chemical composition, density and temperature of the interstellar medium, as well as the temperature and composition of hot young stars. Information about galaxy evolution can also be learned from ultraviolet observations. The observation of celestial objects in the ultraviolet band is very different from the observation of visible light and infrared. Many stars that are relatively cool in visible light and infrared observations appear to be hot objects in ultraviolet observations, especially stars in the early or late stages of evolution. Observations in the far-ultraviolet/near-ultraviolet band are very important for the study of early-type stars (including O, B, and A-type stars), white dwarfs, and central stars of planetary nebulae, because these types of stars show their strongest in the ultraviolet region. Radiation, the importance of ultraviolet observations for late-type stars (including F, G, K, and M types) is similar to that of the sun. Ultraviolet observations are essential to study the chromosphere and corona of stars and the transition layers between them. means.

Ultraviolet astronomy research has important scientific significance and application value. Ultraviolet Sky Survey Spectral Imaging and Imager can study galaxy evolution, interstellar gas composition and important astronomical phenomena in the universe.

SUMMARY OF THE INVENTION

The invention overcomes one of the deficiencies of the prior art and provides an optical imaging system for ultraviolet sky survey, which can realize ultraviolet sky survey observation based on the combination of target imaging and spectral imaging, and has small volume, high precision and simple optical path.

According to an aspect of the present disclosure, the present invention provides an optical imaging system for ultraviolet sky survey, the system comprising: a primary mirror, a secondary mirror, a prism, an imaging filter, a correction lens, and an area array detector;

Wherein, the primary mirror is used for receiving the incident parallel beam and reflecting the parallel beam to the secondary mirror;

The secondary mirror is used to reflect the parallel beam to a prism or an imaging filter; after being filtered by the prism scattering or imaging filter, it is transmitted to the correction by the prism or imaging filter lens;

After the correction lens corrects the aberration of the parallel beam, the parallel beam is imaged on the area array detector;

Wherein, the parallel beam dispersed by the prism is imaged on the area array detector after the phase difference is corrected by the correction lens, and the spectral image of the observation target is obtained;

The parallel light beam filtered by the imaging filter is imaged on the area array detector after the phase difference is corrected by the correcting lens to obtain the observation image of the observation target.

In a possible implementation manner, the spectral image of the observation target and the observation image are focused to the same position through the correction lens.

In a possible implementation, the prism and the imaging filter are switched by a filter wheel of the imaging filter.

In a possible implementation manner, the surface of the primary mirror is an off-axis paraboloid, the surface of the secondary mirror is a hyperboloid, and the imaging filter has a spherical design.

In a possible implementation manner, the front surface of the prism grid is a concave spherical surface, and the rear surface is engraved with grating lines.

In a possible implementation manner, the rear surface of the prismatic grid has an included angle with the optical axis of the prismatic grid, and the scattering direction of the prismatic grid is changed by changing the size of the included angle, so that the spectral images of different observation targets can be obtained. do not overlap.

In a possible implementation manner, the material of the prism, the imaging filter, and the correction lens is fused silica.

In the optical imaging system for ultraviolet sky surveying of the present disclosure, the primary mirror is used for receiving the incident parallel light beam and reflecting the parallel light beam to the secondary mirror; the secondary mirror is used for reflecting the parallel light beam to the prism or the imaging filter; After filtering by prismatic scattering or imaging filter, it is transmitted to the correction lens by the prismatic or imaging filter; after the correction lens corrects the aberration of the parallel beam, the parallel beam is imaged to the area array detection The parallel beam is dispersed by the prism grid, then corrected by the correction lens, and then imaged on the area array detector to obtain the spectral image of the observation target; the parallel beam is filtered by the imaging filter, and then the phase difference is corrected by the correction lens, and then imaged to the area array The observation image of the observation target is obtained on the detector. The ultraviolet sky survey observation with a large field of view can be realized based on the combination of target imaging and spectral imaging, and has the advantages of small size, high precision and simple optical path.

Description of drawings

The accompanying drawings are used to provide a further understanding of the technical solutions or the prior art of the present application, and constitute a part of the specification. The drawings representing the embodiments of the present application together with the embodiments of the present application are used to explain the technical solutions of the present application, but do not constitute limitations on the technical solutions of the present application.

FIG. 1 shows a schematic diagram of an optical imaging system for ultraviolet sky survey according to an embodiment of the present disclosure;

FIG. 2 shows a schematic structural diagram of an optical imaging system for ultraviolet sky survey according to another embodiment of the present disclosure;

FIG. 3 shows a schematic diagram of a spectral dispersion relationship of an optical imaging system for ultraviolet sky survey according to an embodiment of the present disclosure.

Detailed ways

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples, so as to fully understand and implement the implementation process of how the present invention applies technical means to solve technical problems and achieve corresponding technical effects. The embodiments of the present application and the various features in the embodiments can be combined with each other under the premise of no conflict, and the formed technical solutions all fall within the protection scope of the present invention.

Additionally, the steps illustrated in the flowcharts of the figures may be performed in a computer, such as a set of computer-executable instructions. Also, although a logical order is shown in the flowcharts, in some cases the steps shown or described may be performed in an order different from that herein.

FIG. 1 shows a schematic diagram of an optical imaging system for ultraviolet sky survey according to an embodiment of the present disclosure. The optical system is similar to the Cassegrain telescopic system. As shown in Figure 1, the far-ultraviolet spectrometer may include: a primary mirror, a secondary mirror, a prism, an imaging filter, a correction lens, and an area array detector.

Among them, the primary mirror is used to receive the incident parallel beams of different fields of view, and reflect the parallel beams to the secondary mirror; the secondary mirror is used to reflect the parallel beams to the prism 3 or imaging filter; after the prism scattering or imaging filter After filtering, it is transmitted to the correction lens by the prism or the imaging filter; after the correction lens corrects the aberration of the parallel beam, the parallel beam is imaged on the area array detector.

The parallel beam is dispersed by the prism, and then corrected by the correction lens, and then imaged on the area array detector to obtain the spectral image of the observation target; the parallel beam is filtered by the imaging filter, then corrected by the correction lens, and then imaged on the area array detector. Obtain the observation image of the observation target.

Among them, the prism and the imaging filter can be switched by the imaging filter wheel, so that the optical path of the optical system is the prism or the imaging filter, and the prism and the imaging filter are in the same optical path in the optical system. The position of the area array detector remains unchanged between the prism grid and the imaging filter. When there is a prism in the optical path of the optical system, the incident parallel beam is dispersed by the prism and then corrected by the correction lens, and the image on the area array detector is the spectral image of the observation target; when the optical path of the optical system is an imaging filter When the light sheet is used, the incident parallel beam is filtered by the imaging filter and then corrected by the correction lens, and the imaging on the area array detector is the observation image of the observation target.

The incident parallel beam is received through the primary mirror, and the parallel beam is reflected to the secondary mirror; the secondary mirror reflects the parallel beam to the prism or the imaging filter; after being scattered by the prism or the imaging filter, it is filtered by the prism or the imaging filter It is transmitted to the correction lens; after the correction lens corrects the aberration of the parallel beam, the parallel beam is imaged on the area array detector; wherein, the parallel beam is dispersed by the prism and then corrected by the correction lens, and then imaged on the area array detector for observation. The spectral image of the target; the parallel beam is filtered by the imaging filter, then corrected by the correction lens, and then imaged on the area array detector to obtain the observation image of the observation target. The ultraviolet sky survey observation with a large field of view can be realized based on the combination of target imaging and spectral imaging, and has the advantages of small size, high precision and simple optical path.

FIG. 2 shows a schematic structural diagram of an optical imaging system for ultraviolet sky survey according to another embodiment of the present disclosure. The ultraviolet sky survey optical system adopts a prism grid and an imaging filter combined with a reflective telescopic system, which can realize large-field ultraviolet sky survey spectral imaging and imaging observation.

As shown in FIG. 2 , the optical system includes a primary mirror 1 , a secondary mirror 2 , a prism 3 , an imaging filter 4 , a correction lens 5 , and an area array detector 6 . The incident parallel beams of different fields of view are irradiated on the primary mirror 1, and the primary mirror 1 reflects the parallel beams to the secondary mirror 2). To the area array detector 6, when the optical system light passes through the prism 3, the area array detector 6 is a spectral image, and when the optical system light passes through the imaging filter 4, the area array detector (6) is a target image.

In a possible implementation manner, as shown in FIG. 2 , the surface of the primary mirror 1 is an off-axis paraboloid, so that incident parallel light beams in different fields of view can be reflected to the secondary mirror 2 at a certain angle. The surface of the secondary mirror 2 can be a hyperboloid, which can condense the parallel light beams onto the prism 3 . This is just an example, and the surfaces of the primary mirror 1 and the secondary mirror 2 are not limited. One primary mirror 1 may be provided, or multiple primary mirrors may be provided. As shown in FIG. 1 , two primary mirrors 1 are provided, which can receive parallel light beams of different fields of view, which are not limited herein.

In a possible implementation manner, as shown in FIG. 2 , the front surface of the prism grid 3 is a concave spherical surface, and the rear surface is engraved with grating lines. The grating line density is determined according to the size of the spectral image plane on the area array detector 6 and the requirements of the size of the image plane, the size of the detector, and the spectral resolution index. The imaging filter 4 has a spherical design to reduce the aberration of the spectral image plane on the area array detector 6 .

In a possible implementation manner, the rear surface of the prismatic grid has an included angle with the optical axis of the prismatic grid, and the scattering direction of the prismatic grid is changed by changing the size of the included angle, so that the spectral images of different observation targets can be obtained. do not overlap.

Wherein, the rear surface of the prismatic grid has an included angle with the optical axis of the prismatic grid, which can ensure that the position of the area array detector (6) remains unchanged under the two imaging conditions in the optical path system.

According to the grating equation: sinα+sinβ=k*m*λ, where α is the incident angle of the grating, β is the diffraction angle, k is the spectral order, m is the number of fringes per millimeter of the grating, and λ is the wavelength. Since the parallel beam reflected by the secondary mirror 2 in this optical system irradiates the prism 3 in a direction parallel to the optical axis of the prism 3, for this optical system, α≈0, sinβ=k*m*λ .

FIG. 3 shows a schematic diagram of a spectral dispersion relationship of an optical imaging system for ultraviolet sky survey according to an embodiment of the present disclosure.

As shown in FIG. 3 , for a prismatic imaging spectral image, the theoretical grating resolution capability of the prismatic grating is R=n*L*k, where n is the diffraction order of the prismatic grating, and L is the width of the prismatic grating.

The distance x between the imaging position of the spectral image on the surface of the area array detector and the center field of view image of the area array detector is: x=d*tanβ. Since multiple targets in a fixed direction of the prism will have spectral overlap, the scattering direction of the prism can be changed by changing the angle between the prism and its optical axis, so that the spectral images of different observation targets do not overlap. After the aberration of the light beam is corrected by the correction lens, the spectral imaging on the area array detector and the observation image are focused on the same position on the surface of the area array detector.

In addition, the entire optical system is a reflective element. The prism, imaging filter, and correction lens are all made of fused silica. A small working band range can be appropriately selected, and the detection spectral band of the entire optical system can be extended to 2500 nm. .

The parallel beams passing through different fields of view are incident on the primary mirror and then reflected to the secondary mirror; then, after being scattered by the prism or filtered by the imaging filter, it is transmitted to the correction lens by the prism or the imaging filter; the correction lens has a different effect on the parallel beam After correction, it is imaged on the area array detector. After the parallel beam is dispersed by the prism, the spectral image of the observation target is obtained on the area array detector; after the parallel beam is filtered by the imaging filter, the observation image of the observation target is obtained on the area array detector. The ultraviolet sky survey observation with a large field of view can be realized based on the combination of target imaging and spectral imaging, and has the advantages of small size, high precision and simple optical path.

Although the embodiments disclosed in the present invention are as above, the described contents are only the embodiments adopted to facilitate the understanding of the present invention, and are not intended to limit the present invention. Any person skilled in the art to which the present invention belongs, without departing from the spirit and scope disclosed by the present invention, can make any modifications and changes in the form and details of the implementation, but the scope of patent protection of the present invention, The scope as defined by the appended claims shall still prevail.

Claims (7)

1. An ultraviolet roving optical imaging system, comprising: the device comprises a primary mirror, a secondary mirror, a prism grid, an imaging optical filter, a correcting lens and an area array detector;

the primary mirror is used for receiving incident parallel light beams and reflecting the parallel light beams to the secondary mirror;

the secondary mirror is used for reflecting the parallel light beams to the edge grating or the imaging optical filter; after being scattered by the edge grating or filtered by the imaging filter, the light is transmitted to the correcting lens by the edge grating or the imaging filter;

after the correction lens corrects the phase difference of the parallel light beams, the parallel light beams are imaged on an area array detector;

after the parallel light beams are subjected to the grignard dispersion, the parallel light beams are subjected to the aberration correction by the correction lens and then imaged on an area array detector to obtain a spectral image of an observation target; and the parallel light beams are filtered by the imaging optical filter, then are subjected to positive aberration correction by the correction lens, and are imaged on an area array detector to obtain an observation image of an observation target.

2. The ultraviolet roving optical imaging system according to claim 1, characterized in that the spectral image and the observation image of the observation target are focused to the same position by the correction lens.

3. The ultraviolet roving optical imaging system of claim 1, wherein the prisms and imaging filters are switched by a filter wheel of the imaging filter.

4. The ultraviolet roving optical imaging system of claim 1, wherein the primary mirror surface is an off-axis paraboloid, the secondary mirror surface is a hyperboloid, and the imaging filter is of a spherical design.

5. The ultraviolet roving optical imaging system of claim 1, wherein the front surface of the prism is a concave spherical surface and the back surface of the prism is engraved with grating lines.

6. The ultraviolet roving optical imaging system according to claim 5, wherein the rear surface of the prism grid has an included angle with the optical axis of the prism grid, and the scattering direction of the prism grid is changed by changing the size of the included angle, so that the spectral images of different observation targets do not overlap.

7. The ultraviolet roving optical imaging system according to claim 1, wherein the material of the edge grating, the imaging filter and the correcting lens is fused quartz.

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