45 results about "Coronagraph" patented technology

The invention provides a position measurement system and a position measurement method for an outer shield of a coronagraph. Through configuring a laser feedback interference system, reference light and measuring light are adjusted so that the reference light and the measuring light are respectively emitted to the supporting rod and the disc surface of the outer shield, and the reference light and the measuring light are directly reflected by a matt black surface and return along original paths, thereby forming laser feedback and performing measurement. According to the length changes of the measured reference optical path and the measured optical path, displacement change and angle change of the outer shield of the coronagraph can be calculated according to the structures and parameters of the two optical paths. By means of the system and the method, the outer shield can be adjusted to an ideal central position, and furthermore the influence of outer shield position change to stray light of the coronagraph is researched when ambient temperature or vibration testing condition is changed. Through position measurement to the outer shield and quantitative analysis of the stray light, coronagraph design can be further improved and integral stray light level is reduced.

The invention discloses a coronagraph objective lens scattering stray light detection device and a detection method. The detection device comprises a light source, a detection module and a detector. An adjustable diaphragm I, a stray light eliminating diaphragm set, a field lens assembly and an imaging lens assembly are sequentially installed in the light path direction. A to-be-detected lens is arranged between the adjustable diaphragm I and the stray light eliminating diaphragm group and is close to the adjustable diaphragm I. Through the adjustable diaphragm I, the stray light eliminating diaphragm group, the field lens assembly and the imaging lens assembly, stray light beams in the lens barrel are shielded to the greatest extent. Compared with the prior art, the detection device adopting the scheme has the advantages that a direct imaging and direct detection mode is adopted, the detection process is convenient, the detection result is more visual, and the detection complexity anddifficulty are greatly reduced.

The invention discloses a wavefront error correction system and method for inhibiting speckle noises of a coronagraph system. A processor is used for outputting a control voltage signal to an actuator in a first deformable mirror according to light strength information received from an amplitude detector and driving the first deformable mirror to correct a wavefront amplitude error; the processor is used for outputting a control voltage signal to an actuator in a second deformable mirror according to light strength information received from an image surface detector and driving the second deformable mirror to correct a wavefront phase error so as to inhibit the speckle noises of the coronagraph system in a dark hole region of the image surface detector. The invention discloses a wavefront error correction method for inhibiting the speckle noises of the coronagraph system. The method comprises the following steps: firstly, selecting a suitable evaluation function according to the selected coronagraph system; adopting a random gradient descent algorithm to apply disturbance voltage signals to the actuators of the deformable mirrors by a plurality of times of iteration; and finally, enabling the evaluation function to be the minimum so as to correct the wavefront errors and greatly improve the imaging contrast ratio of a coronagraph.

The invention discloses an internally occulting type imaging system of a transmission occulting coronagraph, and aims to solve the problem that stray light is difficult to restrain in the prior art. The system comprises an incident aperture diaphragm, an objective lens, an internally occulting body, a field lens, an Lyot diaphragm, an Lyot spot and a relay lens group which are mounted on an optical axis in a lens cone according to a sequential order after sunlight enters the lens cone, wherein the incident aperture diaphragm is located in the first surface position of the objective lens; the internally occulting body is located in the imaging focal plane position of the objective lens; the Lyot diaphragm is located in the imaging focal plane position, where the incident aperture diaphragm passes through, of the objective lens; the Lyot spot is located in the imaging focal plane position of the field lens; and after sunlight beams are focused by the objective lens, sunlight on a solar photosphere layer is shaded by the internally occulting body, and the obtained light beams are imaged on an image plane CCD (charge coupled device) through the field lens and the relay lens group. The internally occulting type imaging system of the transmission ground-based coronagraph is provided with the internally occulting body and the Lyot spot, ghost images can be effectively blocked, and the stray light restraining capacity of the transmission ground-based coronagraph is further improved, therefore, the system can be used for observing sun corona.

The present invention relates to a device making it possible to study the solar corona on a space mission requiring the formation flight of two satellites: an occulting satellite (OCC), the role of which is to create an artificial eclipse of the sun from the point of view of a coronagraph (10) onboard a second satellite, called carrying satellite (COR). The invention presents the advantage of proposing a formation flight device intended for a solar coronagraphy mission comprising fixed solar panels (11a), requiring no deployment, thanks to a dissymmetrical accommodation of the coronagraph (10) reflected in a shifting of said coronagraph (10) to a side of the carrying satellite (COR).

The invention discloses a method for detecting and tracking CME based on machine learning, and the method achieves the detection and tracking of CME (coronal mass ejection) through four stages of preprocessing, classification, detection and tracking on the basis of a white light coronagraph image. In the preprocessing stage, down-sampling and differential image calculation are carried out on an image. In the classification stage, a supervised image classification method is used to classify a given white-light coronagraph image into a CME type and a CME-free type, and then middle-layer featuresextracted from a trained CNN are used to detect the area of the CME. In the detection stage, a CME area is mined by using an unsupervised image cooperative positioning method. In the tracking stage,an image is converted into a polar coordinate system, CMEs at different positions are divided, some rules are defined to clean and filter the CMEs, and basic parameters of all the detected CMEs are calculated.

The invention provides a high-sensitivity coronagraph stray light detection device, and relates to the field of astronomical target observation and detection. The device comprises a low-brightness solar simulation device, a band-pass filter and a single-photon counting imaging detector. The band-pass filter is arranged between the coronagraph to be measured and the single-photon counting detector,and the single-photon counting detector is arranged on the focal plane of the coronagraph to be measured; the low-brightness solar simulation device emits 32'full-view-field simulated sunlight to enter the coronagraph to be detected, the band-pass filter performs wavelength selection on a wave band to be detected, and the single-photon counting imaging detector detects stray light brightness andsolar sun surface brightness of the coronagraph to be detected. The stray light inhibition capability of the coronagraph can be detected by respectively measuring the solar sun surface radiation and the stray light radiation of the coronagraph, and the difficulty that the stray light inhibition capability of the coronagraph cannot be directly detected by utilizing the solar radiation due to the influence of atmospheric scattering in a low-altitude area is overcome.

Apparatus, and a related method, for eliminating the effect of speckle images caused by surface imperfections in a primary mirror of a stellar coronagraph. Depending on their size, mirror imperfections can result in speckles in a field of view that also includes an image of a distant target planet. By generating a traveling surface wave in the mirror surface, and then tuning the spatial wavelength of the surface wave to approximately match that of a surface imperfection, the speckle image corresponding to that surface imperfection is made to twinkle in irradiance. Tuning the traveling surface wave though a wide range of spatial wavelengths causes each speckle image in turn to be identified by twinkling, while the target planetary image remains unvarying. Accordingly, multiple speckles corresponding to different mirror imperfections may be conveniently eliminated by image processing.

A centralized solar coronagraph light path structure belongs to the field of solar-terrestrial space and comprises an outer diaphragm, an outer shielding occulter, an incidence aperture diaphragm, an objective lens group, a field diaphragm, an inner shielding occulter, a field lens group, an Lyot diaphragm and a relay lens group. The outer diaphragm, the outer shielding occulter, the incidence aperture diaphragm, the objective lens group, the field diaphragm, the inner shielding occulter, the field lens group, the Lyot diaphragm and the relay lens group are arranged on an optical axis in a lens cone according to the sequence of sunlight incidence. The outer shielding occulter and the inner shielding occulter shield direct sunlight from entering an optical system. The field diaphragm is arranged at an objective lens group focal plane position. The inner shielding occulter is arranged at a position where the corona is imaged through the outer shielding occulter, and the outer shielding occulter is arranged at a conjugation position of the inner shielding occulter relative to the objective lens group. The Lyot diaphragm is arranged at a position where the incidence aperture diaphragm is imaged through the objective lens group and the field lens group. The centralized solar coronagraph light path structure is used for shielding direct light of a solar photosphere layer and achieves effective observation of the solar corona.

In a first exemplary embodiment of the present invention, an optical device comprises a telescope, a coronagraph device coupled to the telescope and having a focal plane occulting mask to provide a coronagraphic image, and a reticulate grid element arranged in a light path propagated through the telescope, at a location relative to the coronagraphic image, to create controlled fiducial spots in the coronagraphic image.

The invention provides a stray light testing device and a stray light testing method for a coronagraph. The testing device comprises a laser, a first optical fiber coupler, a polarization maintaining optical fiber, an optical fiber circulator, a beam expander, a second optical fiber coupler, a spectroscope, an oscilloscope and the like. An incident light path and a feedback light path are constructed through the optical components. Based on information such as light intensity and amplitude of an incident light path and a feedback light path, stray light detection of the coronagraph can be completed. The specific method comprises a coronagraph scattered stray light testing method and an outer blindage diffracted light testing method. When the total stray light test of the coronagraph is carried out, the second optical fiber coupler is arranged at the position of a coronagraph detector; when an outer shield edge diffraction light test is carried out, the second optical fiber coupler is arranged at the position of an inner shield of the coronagraph; the stray light level of the coronagraph is determined according to the measurement result of the oscilloscope. According to the device and the method, high-sensitivity detection of weak stray light signals of different sources of the external coronagraph can be realized.

The embodiment of the invention relates to a measuring apparatus and correction method of wavelength drift in different view fields for a narrowband light filter. The correction method of wavelength drift in different view fields for a narrowband light filter includes the steps: cutting-in a scaling light source and a diffusion sheet into an optical path on which the narrowband light filter is; scanning the spectrum of the scaling light source through the narrowband light filter; according to the spectrum of the scaling light source, determining the wavelength drift in different view fields for the narrowband light filter; shifting out the scaling light source and the diffusion sheet from the optical path; scanning the spectrum of an observation target through the narrowband light filter; and according to the wavelength drift in different view fields for the narrowband light filter, calibrating the spectrum of the observation target, and obtaining the real spectrum and the velocity field information of the observation target. The measuring apparatus and correction method of wavelength drift in different view fields for a narrowband light filter can be used for small-bore and large-view-field sun observation of space and ground base, such as a full solar disk photosphere and chromosphere image, can also be used for coronagraph observation of space and ground base to finally realize accurate background calibration of wavelength and velocity field, and can be used for small-bore and large-view-field remote sensing to earth, based on the narrowband light filter.

Systems and methods for attenuating light from undesired sources in a coronagraph apparatus are provided. The coronagraph includes a first imaging lens that receives light representing a desired image and an undesired central image and a reimaging system that mitigates the undesired central image. The reimaging system includes a composite half-wave plate assembly that includes a plurality of angular half-wave plate sections. Each of the plurality of angular half-wave plate sections have two congruent sides that meet at an apex substantially at a center of the composite half-wave plate. A characteristic c-axis associated with a given angular half-wave plate section is aligned differently from the respective characteristic c-axes of at least two angular half-wave plate sections in substantial contact with the two sides of the given angular half-wave plate section. A fixation element engages the half-wave plate sections to maintain the angular half-wave plate sections in a desired arrangement.

The invention discloses a spherical reflection type coronagraph, and belongs to the technical field of coronagraphs. The spherical reflection type coronagraph solves the technical problems that in the prior art, a coronagraph is complex in structure and vignetting and chromatic aberration exist. The coronagraph comprises a primary object lens, a secondary lens, an image-forming mirror, a plane mirror, a first diaphragm, a second diaphragm and a CCD detector. After passing through the first diaphragm, light of the solar photosphere and light of the corona area enter the primary object lens and are reflected to the secondary lens by the primary object lens. The light of the solar photosphere is blocked by a hole of the secondary lens. After being reflected by the secondary lens and the image-forming mirror in sequence, the light of the corona area passes through the second diaphragm, reaches the plane mirror and is deflected to the CCD detector by the plane mirror to form images. After being reflected by the primary object lens, the secondary lens and the image-forming mirror in sequence, diffracted light generated when the light of the solar photosphere shines on the edge of the first diaphragm is blocked by the second diaphragm. The coronagraph is free of influence of chromatic aberration, capable of working at various wave bands and simple in structure, stray light of the reflection coronagraph is effectively restrained, and the geometric dimension of the coronagraph is decreased.

The invention relates to the field of space coronameters, in particular to a dual-mode switching system for a space coronagraph and a switching method thereof. The switching system comprises a self-calibration light source switching device, a light path switching device and a positioning device. A plurality of self-calibration light sources in the self-calibration light source switching device areconnected with a wavelength division multiplexer through optical fibers, and the wavelength division multiplexer is connected with an optical fiber connector. A motor in the light path switching device is connected with a worm, the worm and a worm gear shaft are installed on an outer frame, a worm gear is installed on the worm gear shaft and meshed with the worm, an optical fiber fixing rod is installed at the locking end of the worm gear shaft, and the optical fiber connector is installed on the optical fiber fixing rod. An encoder is connected to the positioning end of the worm gear shaft.The switching method comprises the steps that the encoder obtains angle position information; the worm gear shaft rotates to the position of a calibration angle, and a light path is calibrated; and the worm gear shaft rotates to a zero position, and starlight enters the space coronagraph. By improving the structure, the switching system is high in precision and reliability and small in weight andsize.

The invention discloses a pupil modulation coronagraph system for high-contrast imaging, and relates to the technical field of coronagraph, the pupil modulation coronagraph system comprises a telescope incident end 1, a fixed star simulation light source 2, a collimating lens 3, an aperture diaphragm 4, a pupil modulator 5, an imaging lens 6 and an imaging detector 7, and the two ends of the system are respectively provided with the telescope incident end 1 and the imaging detector 7. The pupil modulator 5 comprises a plurality of modulation bands with different transmittances, the whole modulation band is mainly composed of a plurality of metal film layers with different extinction coefficients, and the extinction coefficients of the metal film layers from the edge areas of the two sides of the whole modulation band to the middle area of the whole modulation band are gradually increased. The invention further discloses a working method of the pupil modulation coronagraph system for high-contrast imaging. According to the pupil modulation coronagraph system for high-contrast imaging and the working method, the transmittance value and the film layer thickness of a modulation band are synchronously optimized, and strong diffraction light of fixed stars is inhibited by combining selection of different coating materials, so that optimal high-contrast imaging is finally obtained.

The invention discloses a spatial broadband ultra-high contrast imaging method and a coronagraph system. According to the method, a pupil transmittance modulation technology is adopted, change modulation of transmittance is carried out in the two-dimensional space direction of a pupil, inhibition of strong light of a fixed star on the axis is achieved, a two-dimensional shape modulation method based on bright and dark strips is adopted, the pupil plane is composed of the bright and dark strips of a limited strip, and by changing the arrangement density distribution of the bright and dark strips, the modulation transmittance is changed, so that the optimal high-contrast imaging is obtained. The system comprises a simulation fixed star light source, a collimating mirror, an aperture diaphragm, a pupil modulation light filter, an imaging mirror and a detector. Aiming at the application of an ultra-high contrast imaging coronagraph in the technical field of broadband imaging, the invention provides and completes the coronagraph system which is suitable for observation with the bandwidth exceeding 5% and even can cover full-band observation. The system can solve the problem that an existing coronagraph is low in light transmission efficiency.

The invention discloses a spatial full-region ultrahigh-contrast imaging method and a coronagraph system. According to the method, a circular ring band pupil transmittance modulation technology is adopted, transmittance gradual change modulation is carried out in the radial direction of a pupil, inhibition of strong diffraction light of a fixed star is achieved, and energy distribution of the fixed star at the pupil position of the system is changed by adopting a limited-band and bilaterally-symmetrical transmittance modulation band in circular ring band pupil transmittance modulation, and the requirement of optimal high-contrast imaging is met. The limited band and the bilaterally-symmetrical transmittance modulation band are composed of limited transmittance modulation ring bands, the ring band modulation gradually changes from the transmittance of a center band, and the left transmittance and the right transmittance are symmetrically distributed from the center band. The coronagraph system suitable for 360-degree working area observation is provided and completed for the technical problem that an ultrahigh-contrast imaging area is limited, the detection efficiency problem of a space coronagraph is solved, the future planet discovery rate and the observation time utilization rate are improved, and the effective life of an extrasolar planet space detection satellite is prolonged.

The present invention relates to the solar corona observation technology field, in particular to a solar corona 3D reconstruction simulation device. The solar corona 3D reconstruction simulation device is equipped with a bottom plate, and is characterized in that a central shaft is arranged in the middle part of the bottom plate, a first shaft sleeve and a second shaft sleeve sleeve the central shaft, a first gear is fixedly connected with the first shaft sleeve, and a second gear is fixedly connected with the second shaft sleeve; the first gear is in three-phase meshing with a gear on the output shaft of a first stepping motor, and the second gear is in four-phase meshing with a gear on the output shaft of a second stepping motor; a bulb is arranged at the upper end of the central shaft,a high-transmittance glass spherical cover sleeves the bulb, and a first connecting rod and a second connecting rod are connected with the first shaft sleeve and the second shaft sleeve respectively;the other end of the first connecting rod and the other end of the second connecting rod are connected with a first external shielding coronagraph and a second external shielding coronagraph respectively, and the first external shielding coronagraph and the second external shielding coronagraph are connected with a PC separately. The solar corona 3D reconstruction simulation device has the advantages of being reasonable in structure, being simple and visual, being convenient for the classroom teaching demonstration, etc.