Astronomical Camera Research Articles

Gamma Spot Monitor at SLEGS beamline

The Gamma Spot Monitor(GSM) at SLEGS beamline is designed to provide a direct view of the gamma beam profile. The main part of the GSM is a LYSO crystal and an astronomical camera. A set of experimental tests on its performance were carried out. The results show that the magnification are 21.0% in X and 21.2% in Y direction, and the relative distortion is proved to be lower than 0.7%. The spatial resolution of the GSM evaluated by the Modulation Transfer Function(MTF) is better than 6.4 lp/mm. The contrast resolution is better than 14%. Beamline alignment is essential in beam modulation, and there are several ways for beamline alignment. In this paper, alignment capability of the GSM is demonstrated, also, the absorption coefficient distribution of a model composed of different materials is shown.

An innovative sCMOS based autonomous astronomical camera dedicated to universal use for SST and other fields of optical astronomy

Creotech Instruments is advancing a game-changing sCMOS camera series. The Final Prototype Model of an astronomical camera for Space Surveillance and Tracking (SST) is in the test campaign phase. Designed for SST, NEO, and debris detection, its adaptable platform suits quantum tech and biological microscopy. Edge computing sets it apart, leveraging FPGA-based SoC for real-time processing and Linux-based pre-processing. Operating autonomously, it supports on-camera ML algorithms, revolutionizing astronomy. Data pre-processing, like frame stacking, reduces data load. This paper introduces the camera's concept, architecture, and prototype test results, emphasizing specific use cases and future product line development.

Research on the Effect of Vibrational Micro-Displacement of an Astronomical Camera on Detector Imaging

Scientific-grade cameras are frequently employed in industries such as spectral imaging technology, aircraft, medical detection, and astronomy, and are characterized by high precision, high quality, fast speed, and high sensitivity. Especially in the field of astronomy, obtaining information about faint light often requires long exposure with high-resolution cameras, which means that any external factors can cause the camera to become unstable and result in increased errors in the detection results. This paper aims to investigate the effect of displacement introduced by various vibration factors on the imaging of an astronomical camera during long exposure. The sources of vibration are divided into external vibration and internal vibration. External vibration mainly includes environmental vibration and resonance effects, while internal vibration mainly refers to the vibration caused by the force generated by the refrigeration module inside the camera during the working process of the camera. The cooling module is divided into water-cooled and air-cooled modes. Through the displacement and vibration experiments conducted on the camera, it is proven that the air-cooled mode will cause the camera to produce greater displacement changes relative to the water-cooled mode, leading to blurring of the imaging results and lowering the accuracy of astronomical detection. This paper compares the effects of displacement produced by two methods, fan cooling and water-circulation cooling, and proposes improvements to minimize the displacement variations in the camera and improve the imaging quality. This study provides a reference basis for the design of astronomical detection instruments and for determining the vibration source of cameras, which helps to promote the further development of astronomical detection.

New detector design of STORNI neutron imaging facility at RA-6 research reactor

The paper describes an upgrade of the neutron imaging facility at the RA-6 research reactor in Argentina. The RA-6 reactor is mainly used for education and training. Still, it is also equipped with several research facilities such as a neutron boron capture therapy facility, neutron activation analysis facility and neutron imaging facility. In 2022, the detection system of the neutron imaging facility was upgraded with the use of an astronomical CMOS camera and a 3D-printed housing. The upgrade was focused on improvements to the optical components resulting in better image quality and spatial resolution.

Astronomical Camera Based on a CCD261-84 Detector with Increased Sensitivity in the Near-Infrared

Herein, we describe the design, implementation and operation principles of an astronomical camera system, based on a large-format CCD261-84 detector with an extremely thick 200 μm substrate. The DINACON-V controller was used with the CCD to achieve high performance and low noise. The CCD system photometric characteristics are presented. A spatial autocorrelation analysis of flat-field images was performed to reveal the dependence of substrate voltage on the lateral charge spreading. The investigation of the dispersion index for the optimal choice of exposure time is discussed. Studies of the patterns of fringes were carried out in comparison with previous detectors. The amplitude of fringes with CCD261-84 was significantly lower, compared to previous-generation detectors. The results of using a new camera for imaging and spectral observations at the Russian 6 m telescope with the SCORPIO-2 multimode focal reducer are considered. The developed CCD camera system makes it possible to significantly increase the sensitivity in the 800–1000 spectral range.

CMOS-based observation of Resident Space Objects using short-exposure stacking mode

To meet the growing demand for the surveillance of resident space objects, the Shanghai Astronomical Observatory has developed a new observation method for monitoring resident space objects using a high frame rate astronomical CMOS camera, called the short-exposure stacking mode. This method can be used to observe objects of various orbit types with high observation accuracy. This paper describes the implementation of this new method of RSO observation, and the observation experiment of one MEO satellite and two GEO satellites using this method with a 40 cm telescope, the observation system has a 0.5°×0.5° field of view. The observation results show that the accuracy of the sensor calibration is 0.3-0.4 arc-second. Compared with the external precision ephemeris, the standard deviation of the residual differences is better than 0.5 arc-second, which means that the precise orbit of space objects can be obtained with enough observation. And compared with the method that uses drift scan CCD, the observation time efficiency of the short-exposure stacking mode is better.

L Band Phased Array Feed Noise Figure and Radiation Efficiency Measurement with the Antenna Y Factor Method

The noise performance of a high sensitivity, wide-field astronomical phased array feed receiver can be characterized by measurements using the antenna Y factor method. These measurements are used to determine figures of merit for an active array receiver. Antenna elements for the Advanced L Band Phased Array Camera for Astronomy (ALPACA) were measured using the antenna Y factor method to determine the active array and receiver noise figure, the antenna loss, receiver equivalent noise temperature, and radiation efficiency of the system over its 500[Formula: see text]MHz operating bandwidth. The completed ALPACA instrument will feature a fully cryogenic design with both the low-noise amplifiers and array elements cryogenically cooled. The uncooled performance measurements from the antenna Y factor method are used to extrapolate the elements cryogenic radiation efficiency and antenna loss showing that it is expected that the elements will contribute less than 1 K to the overall system noise temperature. These results validate the antenna Y factor method to measure key antenna parameters such as the antenna radiation efficiency and show that the instruments front-end array and electronics meets expected performance targets.

Study on performance testing techniques for astronomical optical cameras

Study on performance testing techniques for astronomical optical cameras

Employment of astronomical cameras ZWO ASI120MM for investigation of molecular light scattering

Molecular light scattering – the method allow to determine the intensity and coefficient of scattering of the substance. For most of aqueous solutions, the value of this coefficient is comparable to that for benzene, but an order of magnitude more than for water. Therefore, it is necessary to register the emitting intensity of the order of . For provide such experiments it has been proposed to used the high sensitive astronomical cameras, for eliminate interference, which allowed with physical-chemical processes. The aim of this work is to apply the high sensitive cameras ZWO ASI120MM in the investigation of molecular light scattering. In astronomical research for study the objects with weak light flows (comets, meteors, asteroids), usually used the CCD-cameras. For comparison three types of cameras, which used in the astronomical observations, are given. The CCD-camera VIDEOSCAN-415-2001 has been used for observation of the comets and asteroids, it has a small sizes and can to accumulate the signal without a system of refrigeration. The camera Watec WAT-902H2 ULTIMATE has high sensitive, that allow to fix the fast flying astronomical objects, meteors for example. The CCD-camera DMK 21AU04.AS, which is an analogue of ZWO ASI120MM, has been used for registration of fast processes. This article shows a successful application of the astronomical cameras ZWO ASI120MM in the investigation of molecular light scattering. The scheme of experimental setup using that camera is presented. It is shown that as a result of the experiments, it is possible to determine the intensity of the refracted and main ray and calculate the scattering coefficient for the solutions under study. For work with images obtained as a result of experiments, special software has been created. The developed program “Light” is allowed to conduct to measure the average value of the intensity. In the course of subsequent experiments, when setting new tasks, the software will be refined and improved. In the future, it is planned to use this technique for investigation the water-protein solutions.

Probing Photon Statistics in Adaptive Optics Images with SCExAO/MEC* * Based in part on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

We present an experimental study of photon statistics for high-contrast imaging with the Microwave Kinetic Inductance Detector (MKID) Exoplanet Camera (MEC) located behind the Subaru Coronagraphic Extreme Adaptive Optics System at the Subaru Telescope. We show that MEC measures the expected distributions for both on-axis companion intensity and off-axis intensity, which manifests as quasi-static speckles in the image plane and currently limits high-contrast imaging performance. These statistics can be probed by any MEC observation due to the photon-counting capabilities of MKID detectors. Photon arrival time statistics can also be used to directly distinguish companions from speckles using a post-processing technique called Stochastic Speckle Discrimination (SSD). Here, we give an overview of the SSD technique and highlight the first demonstration of SSD on an extended source—the protoplanetary disk AB Aurigae. We then present simulations that provide an in-depth exploration as to the current limitations of an extension of the SSD technique called Photon-Counting SSD (PCSSD) to provide a path forward for transitioning PCSSD from simulations to on-sky results. We end with a discussion of how to further improve the efficacy of such arrival-time-based post-processing techniques applicable to both MKIDs, as well as other high-speed astronomical cameras.

Результаты сравнения астрономо-геодезического и навигационно-геодезического методов определения составляющих уклонения отвесной линии

The authors present the results of comparing the components of deflection of vertical obtained through astronomical-geodetic and navigational-geodetic methods. The first one is based on comparing astronomical and geodetic coordinates of a location. This method has recently been widely implemented in a digital zenith camera systems using a small-sized digital telescope with an astronomical camera based on CCD or CMOS technologies, a high-precision inclinometer and satellite navigation system receiver. In this case, the combination of a telescope, an astronomical camera and an inclinometer enables determining the local direction of the plumb line, expressed by astronomical coordinates, from observations of stars at the zenith and using high-precision star catalogs. The navigational-geodetic method is based on comparing the results of the normal heights’ increments, defined through geometric leveling, and geodetic heights, computed with the relative method of satellite coordinate determinations. For each method, random and systematic components of the error and its confidence bounds were calculated; the absolute values of the deflection of vertical components at two geographically separated points were compared.

Arrayed wide-field astronomical camera system for spectroscopic surveys on Extremely Large Telescopes: system architecture, proof-of-concept, and enabling technologies

The next generation Extremely Large Telescopes (ELTs) are promising a profound transformation of humanity’s understanding of the universe by opening our eyes to a myriad of previously unseen astronomical objects across cosmic space time. Some of the key observational contributions to this transformation will, once again, be made through large-scale ultradeep spectroscopic surveys. Such surveys will call for a wide-field system to expand field of view and correct atmospheric dispersion beyond what an uncorrected ELT is canonically capable of. Although the traditional monolithic form of field correctors served our needs very well on 2- to 8-m class telescopes, we recognize challenges around scaling this traditional design to the ELT level, and hence, as detailed here, present a fundamentally different architecture, called the arrayed wide-field astronomical corrector system or AWACS, for the ELTs of two-mirror construction. The AWACS accomplishes field expansion via an array of small units populated over a telescope’s focal surface, compensating for field aberrations and atmospheric dispersion locally but simultaneously. The AWACS units share one common electro-opto-mechanical design, permitting cost-effective high-volume part manufacturing. We detail the architectural features and proof-of-concept on-sky demonstration of the AWACS. In addition, we highlight our recent development results of randomly nano-textured antireflective (AR) surface structures in terms of an immediately viable, super-broadband, high-performance AR solution for not only the AWACS optics, but also broader ranges of electro-optical devices, particularly those subjected to harsh environments such as high-power laser, cryogenic, and space systems. With continuous advances in other relevant fields, the AWACS is uniquely positioned to enable, either by itself or by complementing traditional correctors, wide-field multi-object spectroscopic surveys in the ELT era and beyond.

APPARILLO: a fully operational and autonomous staring system for LEO debris detection

For safe operation of active space crafts, the space debris population needs to be continuously scanned, to avoid collisions of active satellites with space debris. Especially the low Earth orbit (LEO) shows higher risks of collisions due to the highest density of orbital debris. Laser ranging stations can deliver highly accurate distance measurements of debris objects allowing precise orbit determination and more effective collision avoidance. However, a laser ranging station needs accurate a priori orbit information to track an orbital object. To detect and track unknown orbital objects in LEO, here, a passive optical staring system is developed for autonomous 24/7 operation. The system is weather-sealed and does not require any service to perform observations. To detect objects, a wide-angle imaging system with 10° field of view equipped with an astronomical CCD camera was designed and set up to continuously observe the sky for LEO objects. The system can monitor and process several passing objects simultaneously without limitations. It automatically starts an observation, processes the images and saves the 2D angular measurements of each object as equatorial coordinates in the TDM standard. This allows subsequent initial orbit determination and handover to a laser tracking system. During campaigns at twilight the system detected up to 36 objects per hour, with high detection efficiencies of LEO objects larger than 1 m3. It is shown that objects as small as 0.1 m3 can be detected and that the estimated precision of the measurements is about 0.05° or 7 × the pixel scale.

Appraisal of Low-Cost Pushbroom Hyper-Spectral Sensor Systems for Material Classification in Reflectance.

Near infrared (NIR) remote sensing has applications in vegetation analysis as well as geological investigations. For extra-terrestrial applications, this is particularly relevant to Moon, Mars and asteroid exploration, where minerals exhibiting spectral phenomenology between 600 and 800 nm have been identified. Recent progress in the availability of processors and sensors has created the possibility of development of low-cost instruments able to return useful scientific results. In this work, two Raspberry Pi camera types and a panchromatic astronomy camera were trialed within a pushbroom sensor to determine their utility in measuring and processing the spectrum in reflectance. Algorithmic classification of all 15 test materials exhibiting spectral phenomenology between 600 and 800 nm was easily performed. Calibration against a spectrometer considers the effects of the sensor, inherent image processing pipeline and compression. It was found that even the color Raspberry Pi cameras that are popular with STEM applications were able to record and distinguish between most minerals and, contrary to expectations, exploited the infra-red secondary transmissions in the Bayer filter to gain a wider spectral range. Such a camera without a Bayer filter can markedly improve spectral sensitivity but may not be necessary.

Research on the readout noise suppression method for digital correlated double sampling

As the areas of CCD detectors and CCD mosaics have become larger and larger, the number of readout channels in astronomical cameras has increased accordingly to keep the image readout time within an acceptable range. For the large area cameras or the mosaic cameras, the analog Correlated Double Sampling (aCDS) circuit used in traditional astronomical cameras for suppressing readout noise is difficult to integrate into the camera controllers within the constraints of the space and energy consumption. Recently, digital CDS (dCDS) technology has been developed to solve this problem, which also offers novel analysis and noise suppression methods. In this study, a mathematical model is presented to conveniently analyze the frequency characteristic of a dCDS circuit, which is then simulated by a numerical method for investigating the noise suppression capability with different sampling weights. Importantly, using this model, the extreme point with lowest readout noise can be predicted for a certain dCDS model; and for a specific CCD readout frequency, readout noise can be suppressed by selecting the proper dCDS model. A testing system is then constructed for validating the efficiency of the proposed method.

Research of binary neutron star merger phenomenon by high speed sweeping observation

The pursuit of astronomical research has vastly expanded and illuminated our understanding of physics and the laws of the universe. This, in turn, is knowledge useful to a wide range of applications, many that would not have been foreseen in the original research. Astronomy helped create accurate navigation and mapping whilst technologies developed in the pursuit of the stars can be found in many key, everyday devices. Despite millennia of combing the night skies, there are still many mysteries about the universe that we do not yet understand. Professor Toshikazu Shigeyama and Associate Professor Shigeyuki Sako based at the Research Center for the Early Universe (RESCEU) and Institute of Astronomy (IoA), The University of Tokyo, Japan, are two astronomers working to uncover new information about our universe. They have led a team of researchers who were responsible for creating a new astronomical camera, the Tomo-e Gozen. This device will be capable of helping to shed light on several unknowns through the use of sensors able to capture images much closer together in time than ever before.

Astronomical survey camera shutter locking mechanism design, analysis, and testing

During the launch phase of a survey camera, its shutter will experience a harsh dynamic environment. We propose an elastic compression scheme to prevent the shutter blade from hitting the surrounding structure. The elastic member has a maximum stress at each stage of locking. In order to make this stress as small as possible, we optimize the thickness of the elastic member from 1070 to 666 MPa, which meets the safety factor requirement. We perform finite element simulations and experiments on the locking mechanism, and the results show that the motor torque curves obtained from theoretical calculations, simulation analysis, and tests coincide well. The maximum locking torque of the locking mechanism obtained by theoretical calculations, simulation analysis, and experiments also coincide well, and all three of them are within the design target of about 25 N m, which meets the requirements of shutter locking torque greater than 20 N m. Our proposed elastic compression scheme effectively solves the problem of blade fixation during the shutter launch phase.

Astronomical survey camera shutter locking mechanism design and analysis and testing

Astronomical survey camera shutter locking mechanism design and analysis and testing

2019 outburst of 15-Bootids (IAU#923, FBO) and search strategy to find the potentially hazardous comet

The CAMS BeNeLux and UAE Astronomical Camera Network meteor shower surveys detected a FWHM ​= ​1.8-h wide outburst of 15-Bootids on April 21/22, 2019. Both networks had clear skies throughout the night, but only between 21h28m and 00h13m UTC were meteors from this shower detected. The measured orbit is that of a Halley-type or Long-Period comet. If the shower is an encounter with the 1-revolution dust trail of a Long-Period comet, then that parent comet is a potential impact hazard. The long duration of the outburst suggests comparatively high ejection speeds from, presumably, a large nucleus. The orbit offers guidance for early comet recovery and a search strategy is described. The orbital elements resemble those of bright comet C/539 W1, which may be the parent comet.

Maturing electron multiplying charge coupled device photon-counting with variable multiplication gain imaging for a coronagraphic instrument.

This is an introduction to a US government program that conducted high-contrast imaging experiments with an electron multiplying charge coupled device (EMCCD) in an interferometric coronagraph. This report will introduce the concepts of "charge blooming" and "starlight saturation" in the context of high-contrast astronomical imaging. These phenomena adversely effect the performance of high-contrast photon-counting instruments that do not use a mask to physically block starlight in the science channel of the coronagraph. The problems will be presented with the help of images taken with a commercial EMCCD camera in the visible nulling coronagraph at the Goddard Space Flight Center. A new clocking scheme for EMCCDs-variable multiplication gain clocking-will be proposed as a means for suppressing horizontal blooming and starlight saturation in an astronomical camera. This opening report will conclude with a discussion of design considerations for a new controller for high-contrast photon-counting with an EMCCD in a coronagraphic instrument. This controller will allow a single frame from an EMCCD to be scanned in multiple modes-photon-counting and digitization-with a variable multiplication gain clock to enable direct imaging of an exoplanet and wavefront control of a coronagraph, simultaneously.