A polarization observation device and polarization observation method for night astronomical telescope

Abstract

The present application discloses a polarization observation device and polarization observation method for a night astronomical telescope. The gear assembly in the polarization observation device includes a driving gear, a double reduction gear and a driven gear that are meshed in sequence; a stepper motor can drive the driving gear to rotate; a polarization optical sheet is assembled in the middle hollow position of the driven gear; the driven gear is assembled on a base in a white light observation hole position on a preset rotating wheel installed in the rotating wheel mechanism of the night astronomical telescope through a bearing; a control board and a lithium battery are arranged on the base, and a microprocessor is arranged on the control board; the control board is electrically connected to the stepper motor; a mounting hole for a magnet is arranged on the driven gear, and the magnet is installed in the mounting hole, and the Hall sensor cooperates with the magnet. One technical effect of the present invention is that the present invention has a clever structure, simple observation operation, and can use existing night astronomical telescopes to achieve polarization observation. The device of the present invention has achieved good observation results in the largest night astronomical telescope in China, the Lijiang 2.4-meter telescope, and has realized the only night astronomical polarization observation in China. It is also suitable for domestic 2-meter telescopes and future large telescopes, such as the Xinglong 2.16-meter telescope and the 12-meter telescope of the project.

Description

Technical Field

[0001] The present application belongs to the technical field of astronomical instruments, and specifically, relates to a polarization observation device and observation method for a night astronomical telescope. Background Art

[0002] Polarimetry is a powerful tool for studying the physical properties of astronomical objects. The study of polarimetry data can reveal the radiation mechanism of celestial bodies and provide the possibility for studying the geometric characteristics of celestial bodies. In the field of observation-based astronomy, polarimetry plays an important role in detecting related physical quantities. At present, in domestic night astronomy telescopes, the observation terminals mainly realize photometry and spectrum measurement, and do not realize the function of polarimetry.

[0003] Therefore, it is necessary to provide a polarization observation device for a night astronomical telescope. Summary of the invention

[0004] An object of the present invention is to provide a new technical solution for a polarization observation device for a night astronomical telescope.

[0005] According to one aspect of the present invention, the present invention provides a polarization observation device for a night astronomical telescope, comprising a base and a control card board, a lithium battery, a stepper motor, a gear assembly, a polarization optical sheet, a bearing, a magnet and a Hall sensor arranged on the base;

[0006] The gear assembly comprises a driving gear, a double reduction gear and a driven gear meshed in sequence; the stepping motor is connected to the driving gear and can drive the driving gear to rotate; the middle of the driven gear is hollowed out, and the polarizing optical sheet is mounted on the hollowed-out position; the driven gear is mounted on the base through a bearing, and the base is configured to be mounted in a white light observation hole position on a preset rotating wheel in a rotating wheel mechanism of a night astronomical telescope;

[0007] A U-shaped groove is provided on the base, and the U-shaped groove is configured to be used for installing a control card board and a lithium battery. A microprocessor is provided on the control card board; the control card board is electrically connected to the stepper motor; a mounting hole for a magnet is provided on the driven gear, and the magnet is installed in the mounting hole; the Hall sensor is provided between the tooth surface of the driven gear and the bearing, and the Hall sensor cooperates with the magnet.

[0008] Optionally, the transmission ratio of the gear assembly is 36:1; the stepper motor drives the polarizing optical plate to rotate with an accuracy of 0.5° / step.

[0009] Optionally, a remote terminal is further included, a wireless transmission module is arranged on the control card board, the wireless transmission module is electrically connected to the microprocessor, and the remote terminal is wirelessly connected to the wireless transmission module.

[0010] Optionally, the microprocessor includes an STM32 microprocessor; the wireless transmission module is a Bluetooth module, and the Bluetooth module includes a TI CC2541F256 chip.

[0011] Optionally, the stepper motor and the double reduction gear are fixed on the base and are located outside the driven gear;

[0012] Optionally, a Hall sensor is included, and the sensing position of the magnet and the Hall sensor is the initial 0° position of the rotation angle;

[0013] Optionally, the night astronomy telescope includes a faint celestial body spectroscopic imager.

[0014] Optionally, the preset rotating wheel in the rotating wheel mechanism of the night telescope is a YFUB wheel.

[0015] According to another aspect of the present invention, the present invention also provides a polarization observation method for a night astronomical telescope, comprising the following steps:

[0016] Install the above polarization observation device into the night astronomical telescope;

[0017] Rotate the polarizing optical sheet into the optical path of the night telescope so that the incident light enters the polarizing optical sheet after passing through the filter and finally enters the CCD camera;

[0018] The microprocessor controls the gear assembly to drive the polarized optical sheet to rotate to 0°, 45°, 90°, and 135°, respectively, and obtains the intensity values ​​of the target star at four polarized optical sheet rotation angles in the preset band: I1, I2, I3, and I4;

[0019] The polarization degree πl is calculated by obtaining the intensity values ​​of the target star at the rotation angles of the four polarization optical sheets in the preset band.

[0020] Optionally, the calculation method of the polarization degree πl is:

[0021] I1=(I+Q) / 2,

[0022] I2=(I+U) / 2,

[0023] I 3 = (IQ) / 2,

[0024] I 4 = (IU) / 2, find I, Q and U;

[0025] Substitute the obtained I, Q and U into the formula Calculate the degree of polarization πl.

[0026] A technical effect of the present invention is that the present invention has an ingenious structure, simple observation operation, and can realize polarization observation by using an existing night astronomical telescope. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0028] Figure 1 It is a schematic diagram of the structure of some embodiments of the present application;

[0029] Figure 2 It is a partial structural schematic diagram of some embodiments of the present application;

[0030] Figure 3 It is a structural schematic diagram of a night astronomical telescope in the prior art of this application;

[0031] Figure 4 This application Figure 3 Schematic diagram of the side view structure of the YFUB wheel in the middle.

[0032] Figure 5 It is a schematic diagram of the observation process in some embodiments of the present application.

[0033] Figure 6 It is a schematic diagram of a control circuit in one embodiment of the present application.

[0034] In the figure: 1 base, 2 control card board, 3 gear assembly, 31 driving gear, 32 double reduction gear, 33 driven gear, 4 stepping motor, 5 polarization optical sheet, 6 bearing, 7 magnet, 8 Yunnan faint celestial body spectroscopic imager, 81 YFUA wheel, 82 YFUB wheel, 83 APERTURE wheel, 84 FILTER wheel, 85 GRISM wheel, 86 CCD camera, 9 JV filter. DETAILED DESCRIPTION

[0035] The following will describe the implementation methods of the present application in detail with the help of accompanying drawings and examples, so that the implementation process of how the present application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0036] The present invention provides a polarization observation device for a night astronomical telescope. In some embodiments, reference is made to Figures 1 to 6 It includes a base 1 and a control card board 2, a lithium battery, a stepper motor 4, a gear assembly 3, a polarizing optical sheet 5, a bearing 6, a magnet 7 and a Hall sensor arranged on the base 1.

[0037] The appearance of the base 1 is usually the same as the size of the base for installing the filter on the preset rotating wheel on the rotating wheel mechanism in the preset night astronomical telescope, which is convenient for fitting and installation.

[0038] The gear assembly 3 includes a driving gear 31, a double reduction gear 32 and a driven gear 33 that are meshed in sequence. The stepper motor 4 is connected to the driving gear 31 and can drive the driving gear 31 to rotate. The middle of the driven gear 33 is hollowed out, and the polarizing optical plate 5 is assembled in the hollowed-out position, so that when the driven gear 33 rotates, it can drive the polarizing optical plate 5 to rotate synchronously. The transmission ratio of the gear assembly 3 can be set to 36:1. The stepper motor can be selected to count 20 steps in total. The rotation accuracy of the stepper motor 4 driving the polarizing optical plate 5 can be set to 0.5° / step. The stepper motor can count to determine the rotation angle of the polarizing optical plate.

[0039] The driven gear 33 is mounted on the base 1 through a bearing 6, so that the driven gear 33 can rotate relative to the base 1. The bearing 6 is an ultra-thin ball bearing 6. The base 1 can be installed in a white light observation hole position on a preset rotating wheel in a rotating wheel mechanism of a night astronomical telescope, so that the device is fixed in the night astronomical telescope and the polarized optical sheet 5 can enter the light path of the night astronomical telescope.

[0040] The stepper motor 4 and the double reduction gear 32 are fixed on the base 1 and are located outside the driven gear 33 , which saves the thickness and space requirements of the device and does not obstruct the light path of the polarizing optical sheet 5 .

[0041] The base 1 is provided with a U-shaped groove for mounting the control card board 2 and the lithium battery. The control card board 2 is U-shaped, and the inner dimension of the U is slightly larger than the outer diameter of the driven gear 33, so that the control card board 2 can be located outside the driven gear 33, saving the thickness space requirement of the device. The lithium battery is a strip-shaped lithium battery, which is easy to install in the U-shaped groove, fits the shape of the groove as much as possible and has a larger battery capacity. Furthermore, a protruding mounting portion can be provided on the control card board 2, and the control card board 2 is fixed to the base 1 using screws passing through the mounting portion.

[0042] A microprocessor is provided on the control card board 2. The microprocessor is electrically connected to the stepper motor 4 and can send a control signal to the stepper motor 4 to control the rotation of the stepper motor 4. Further, the microprocessor includes an STM32 microprocessor.

[0043] In some embodiments, the present invention further includes a remote terminal such as an industrial computer. A wireless transmission module is provided on the control card board 2, and the microprocessor is electrically connected to the wireless transmission module to transmit signals. The remote terminal such as the industrial computer can be electrically connected to the wireless transmission module to transmit and receive signals. The industrial computer is electrically connected to the microprocessor through the wireless transmission module to control the rotation of the stepper motor 4, thereby controlling the relative rotation angle of the polarizing optical sheet 5 in the optical path, which is more convenient to control. Furthermore, the wireless transmission module is a Bluetooth module, and the Bluetooth module can include a TI CC2541F256 chip.

[0044] The driven gear 33 is provided with a mounting hole for the magnet 7. The magnet 7 is mounted in the mounting hole without protruding from the tooth surface of the driven gear 33, thereby reducing the thickness and space requirements. The Hall sensor is arranged between the tooth surface of the driven gear 33 and the bearing 6, that is, arranged at a position on the bearing 6 relative to the rotation of the driven gear 33. The spacing between the tooth surface of the driven gear 33 and the bearing 6 is controlled within 2 mm. The Hall sensor cooperates with the magnet 7. The Hall sensor may be located on the rotation path of the magnet 7, so that the magnet 7 can sense and send a signal when it rotates to be relative to the Hall sensor, which is used to locate and calibrate the angle of the polarized optical sheet 5. Further, one Hall sensor may be provided, and the sensing position of the magnet 7 and the Hall sensor is the initial 0° position of the rotation angle; or multiple Hall sensors may be provided, which are preset at different positions to mark different rotation angles of the polarized optical sheet 5, so as to improve the rotation accuracy of the polarized optical sheet 5.

[0045] When the present invention is used, the filter is installed in a white light observation hole position on a preset rotating wheel in the rotating wheel mechanism of the night astronomical telescope, the polarized optical sheet 5 is rotated into the optical path, and the other rotating wheels of the rotating mechanism are adjusted to form an optical path. The stepper motor 4 is controlled by a microcontroller to drive the polarized optical sheet 5 to rotate to different angles, and the CCD camera 86 is used for reading, so as to obtain the corresponding intensity values ​​at different rotation angles, and further obtain the polarization degree πl by calculation to achieve polarization observation. The technical effect of the present invention is that the present invention has a clever structure, simple observation operation, and can use the existing night astronomical telescope to achieve polarization observation. In addition, the original function of the night astronomical telescope is not changed. When observing white light, the device can be disassembled by disassembling the base 1. The installation is convenient and fast, and there is no functional conflict with the original observation instruments and equipment; the rotating wheel mechanism of the night astronomical telescope is used to rotate, and it can quickly switch between conventional observation and polarization observation, which greatly improves the utilization of existing equipment and its use value. Compared with purchasing professional instruments, the manufacturing cost is low. When using a remote terminal for control, the polarizing optical plate 5 can be controlled to rotate to a desired angle as needed; when a remote terminal is not used, it can also be rotated to several preset fixed angles according to a preset program under the control of a microprocessor.

[0046] Specific embodiment 1, reference Figures 1 to 5 , including a base 1 and a control card board 2, a lithium battery, a stepper motor 4, a gear assembly 3, a polarizing optical sheet 5, a bearing 6, a magnet 7 and a Hall sensor arranged on the base 1. The gear assembly 3 includes a driving gear 31, a double reduction gear 32 and a driven gear 33 that are meshed in sequence. The stepper motor 4 is connected to the driving gear 31 and can drive the driving gear 31 to rotate. The driven gear 33 is hollow in the middle, and the polarizing optical sheet 5 is assembled at the hollow position. The driven gear 33 is assembled on the base 1 through a bearing 6. The stepper motor 4 and the double reduction gear 32 are fixed on the base 1 and are located on the outside of the driven gear 33. The filter is provided with a U-shaped groove, and the U-shaped groove is provided with a control card board 2 and a strip lithium battery. The control card board 2 is provided with an STM32 microprocessor and a Bluetooth module including a TICC2541F256 chip; the control card board 2 is electrically connected to the stepper motor 4; the driven gear 33 is provided with a mounting hole for the magnet 7, and the magnet 7 is installed in the mounting hole. A Hall sensor is provided between the tooth surface of the driven gear 33 and the bearing 6, and the Hall sensor is located on the rotation path of the magnet 7. The sensing position of the magnet 7 and the Hall sensor is the initial 0° position of the rotation angle; the transmission ratio of the gear assembly 3 is 36:1; the stepper motor 4 drives the rotation accuracy of the polarizing optical plate 5 to be 0.5° / step.

[0047] The night astronomical telescope uses the Yunnan 2.4m faint celestial body spectrograph, which is a terminal instrument developed by the Niels Bohr Institute of the University of Copenhagen, Denmark, which combines multi-color photometry and medium and low dispersion spectral observation. It contains five sets of rotating wheel mechanisms: YFUA wheel (A wheel), YFUB (B wheel), APERTURE (slit wheel), FILTER (filter wheel), GRISM (grid wheel). There are different numbers of spatial positions on each wheel for installing various optical elements, and there must be at least one "empty" position (to ensure white light observation). The YFUA and B wheels have 5 positions respectively for installing different filters. Rotating the YFUA and B wheels can transfer different filters into the optical path to meet different observation needs. The device of the present invention uses a position on the YFUB wheel to load the device of the present invention, and then remotely controls the precise rotation of the patented invention device to achieve polarization measurement. The device is installed on the YFUB wheel, and its space is limited, and the total thickness of the device does not exceed 12mm. The micro stepper motor 4 used in this patent has a diameter of 8mm and a height of 12mm (including the motor gear), an outer diameter of the optical polarizing optical plate of 50.8mm and a thickness of 5mm, and is installed in the driven gear 33.

[0048] The V band is used as an example for polarization observation. Figure 5 The microprocessor controls the gear assembly 3 to drive the polarization optical plate 5 to rotate to 0°, 45°, 90°, and 135° respectively, and obtains the intensity values ​​of the target star at the four polarization optical plate rotation angles in the V band: I1, I2, I3, and I4 respectively; the polarization degree πl is calculated by the obtained intensity values ​​of the target star at the four polarization optical plate rotation angles in the V band. The calculation method of the polarization degree πl is:

[0049] I1=(I+Q) / 2,

[0050] I2=(I+U) / 2,

[0051] I 3 = (IQ) / 2,

[0052] I 4 = (IU) / 2, find I, Q and U;

[0053] Substitute the obtained I, Q and U into the formula The polarization degree πl is obtained from the equation πl. This enables polarization observation using a night telescope.

[0054] The device of the present invention has achieved good observation results in the largest night astronomical telescope in China - the Lijiang 2.4-meter telescope, realizing the only night astronomical polarization observation in China. It is also suitable for domestic 2-meter-class telescopes and future large telescopes, such as the Xinglong 2.16-meter telescope and the 12-meter telescope that has been approved.

[0055] According to another aspect of the present invention, the present invention also provides a polarization observation method for a night astronomical telescope, comprising the following steps:

[0056] Install the above polarization observation device into the night astronomical telescope;

[0057] The polarized optical sheet 5 is rotated into the optical path of the night telescope, the filter on the rotating wheel in front of the polarized optical sheet 5 is rotated into the optical path, and the rotating wheels of the other optical lenses are adjusted to the white light position, so that the incident light enters the polarized optical sheet 5 after passing through the filter, and finally enters the CCD camera 86. For example, the Yunnan 2.4m faint celestial body spectroscopic imager is selected, the JV filter 9 on the YFUA wheel (A wheel) is rotated into the optical path, the polarization observation device is set on the YFUB (B wheel) The white light hole position is rotated into the optical path, and the APERTURE (slit wheel), FILTER (filter wheel), and GRISM (grating wheel) are all rotated into the white light position.

[0058] The microprocessor controls the gear assembly 3 to drive the polarized optical sheet 5 to rotate to 0°, 45°, 90°, and 135° respectively, and uses the CCD camera 86 and the back-end processing to obtain the intensity values ​​of the target star at the four polarized optical sheet rotation angles in the preset band: I 1, I 2, I 3, and I 4;

[0059] The polarization degree πl is calculated by obtaining the intensity values ​​of the target star at the rotation angles of the four polarization optical sheets in the preset band.

[0060] The calculation method of the polarization degree πl is:

[0061] I1=(I+Q) / 2,

[0062] I2=(I+U) / 2,

[0063] I 3 = (IQ) / 2,

[0064] I 4 = (IU) / 2, find I, Q and U;

[0065] Substitute the obtained I, Q and U into the formula Calculate the degree of polarization πl.

[0066] In specific embodiment 2, the preset band takes the V band as an example, and the high polarization standard star HD204827 is observed at 48 minutes on October 21, 2019; the polarization optical sheet 5 is measured to rotate to 0°, 45°, 90°, and 135° respectively, and the intensity values ​​of the target star at the four polarization optical sheet rotation angles in the V band are calculated by the following formulas;

[0067] I 1=(I+Q) / 2, I 2=(I+U) / 2, I 3=(IQ) / 2, I 4=(IU) / 2, find I, Q and U;

[0068] Substitute the obtained I, Q and U into the formula to calculate the polarization degree πl.

[0069] The preliminary observation results show that the high-polarization standard star HD204827 has a nominal polarization degree of 5.3% (V band). Our measured data polarization degree πl is 4.95% (V band), which basically meets the usage requirements.

[0070] For example, certain words are used in the specification and claims to refer to specific components or methods. Those skilled in the art should understand that different regions may use different nouns to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components. For example, "including" mentioned throughout the specification and claims is an open term, so it should be interpreted as "including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect. The subsequent description of the specification is a preferred embodiment of the present application, but the description is for the purpose of illustrating the general principles of the present application, and is not used to limit the scope of the present application. The scope of protection of the present application shall be determined by the attached claims.

[0071] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a product or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such a product or system. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the product or system including the elements.

[0072] The above description shows and describes several preferred embodiments of the invention, but as mentioned above, it should be understood that the invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the invention concept described herein through the above teachings or the technology or knowledge of the relevant field. Changes and modifications made by those skilled in the art should be within the scope of protection of the claims attached to the invention without departing from the spirit and scope of the invention.

Claims

1. A polarization observation method for a night astronomical telescope, characterized in that: The following steps are involved: Installing a polarization observation device for a night astronomical telescope into the night astronomical telescope; Rotate the polarizing optical sheet into the optical path of the night telescope so that the incident light enters the polarizing optical sheet after passing through the filter and finally enters the CCD camera; The microprocessor drives the polarized optical sheet to rotate to 0°, 45°, 90°, and 135° respectively by controlling the gear assembly, and obtains the intensity values ​​of the target star at the four polarized optical sheet rotation angles in the preset band: I1, I2, I3, and I4; The polarization degree π1 is calculated by obtaining the intensity value of the target star at the rotation angles of the four polarization optical sheets in the preset band; The polarization observation device for a night astronomical telescope comprises a base and a control card board, a lithium battery, a stepping motor, a gear assembly, a polarization optical sheet, a bearing, a magnet and a Hall sensor arranged on the base; The gear assembly comprises a driving gear, a double reduction gear and a driven gear meshed in sequence; the stepping motor is connected to the driving gear and can drive the driving gear to rotate; the middle of the driven gear is hollowed out, and the polarizing optical sheet is mounted on the hollowed-out position; the driven gear is mounted on the base through a bearing, and the base is configured to be mounted in a white light observation hole position on a preset rotating wheel in a rotating wheel mechanism of a night astronomical telescope; The base is provided with a U-shaped groove, and the U-shaped groove is configured to install a control card board and a lithium battery, and a microprocessor is provided on the control card board; the control card board is electrically connected to the stepper motor; the driven gear is provided with a mounting hole for a magnet, and the magnet is installed in the mounting hole, and the Hall sensor is arranged between the tooth surface of the driven gear and the bearing, and the Hall sensor cooperates with the magnet; The transmission ratio of the gear assembly is 36:1; the stepper motor drives the polarizing optical plate to rotate with an accuracy of 0.5° / step; A remote terminal is also included. A wireless transmission module is provided on the control card board. The wireless transmission module is electrically connected to the microprocessor. The remote terminal is wirelessly connected to the wireless transmission module. The microprocessor includes an STM32 microprocessor; the wireless transmission module is a Bluetooth module, and the Bluetooth module includes a TI CC2541 F256 chip; The stepper motor and the double reduction gear are fixed on the base and are located outside the driven gear; A Hall sensor is included, and the sensing position of the magnet and the Hall sensor is the initial 0° position of the rotation angle; The night astronomical telescope includes a faint celestial body spectroscopic imager; The preset rotating wheel in the rotating wheel mechanism of the night telescope is a YFUB wheel; The calculation method of the polarization degree π1 is: I1=(I+Q) / 2, I2=(I+U) / 2, I3=(IQ) / 2, I4 = (IU) / 2, find I, Q and U; Substitute the obtained I, Q and U into the formula Calculate the degree of polarization π1.

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