Astronomical Algorithms Research Articles

Symmetrical Spread of the Sun’s Position at the Equator

Buildings that use renewable energy sources, such as sunlight with solar collector technology, are in demand to face climate change. The position of the sun is a pivotal reference for determining the optimum of solar collectors. There are two differences in the optimum results in the equatorial region due to the different perceptions in defining the sun’s position. This study highlights the optimum orientation that is not perpendicular because it reflects the actual position that spreads at the equator. This study aims to prove the sun’s position that spreads in the equatorial region and to show the optimum potential with varied accesses. The investigation is conducted through the angular coordinates of altitude and azimuth. The methodology used is simulation calculation and descriptive analysis by comparison. The simulation calculation uses SunEarthTools.com, based on equations from astronomical algorithms by Michalsky. The validation uses the NOAA Solar Position Calculator, based on equations from astronomical algorithms by Meeus. The targets of the study are to make a profile of the performance of the sun’s position and a profile of the opportunity for the sloped surfaces to accept access. The sun-earth relationship and the season period are the factors that cause differences in the angular range of the sun’s position for each latitude zone. The results prove that the equatorial region has a more spacious range of orientation and a relatively balanced high of elevation in the four main cardinal directions than other regions. The highest points occur twice during the equinoxes for the balanced position between the east and west orientations, and the farthest points happen in the summer solstices for the balanced position between the north and south orientations. The spreading position allows two low-inclined surfaces facing opposite orientations to be exposed simultaneously for long periods, especially in the equinoxes. This study contributes a theoretical insight into the optimum at the equator that has potency for optimum with diverse access.

A horizontal single-axis tracking bracket with an adjustable tilt angle and its adaptive real-time tracking system for bifacial PV modules

An efficient photovoltaic (PV) tracking system enables solar cells to produce more energy. However, commonly-used PV tracking systems experience the following limitations: (ⅰ) they are mainly applied to single-sided PV panels; (ⅱ) they employ conventional astronomical algorithms that cannot adjust the tracking path in real time according to variable weather. In this study, a model of horizontal single-axis tracking bracket with an adjustable tilt angle (HSATBATA) is developed, and the irradiance model of moving bifacial PV modules is designed, which considers the mounting height, spacing and ground shading of PV panels. Furthermore, an adaptive real-time tracking (ARTT) algorithm is put forward to obtain the optimal tracking path for PV cells, which considers the energy consumption of tracking motors, the front and back irradiance of solar cells, cell temperature and ambient wind speed. The test results indicate that the presented ARTT algorithm enhances the energy of PV modules by 32.7 % and 7.5 %, respectively, compared to the fixed bracket and the conventional tracking algorithm. Additionally, the number of motor starts of the PV tracking system is reduced by 71.7 % compared with that of the conventional algorithm, which greatly contributes to extending the service life of PV tracking brackets and lowering the cost of electricity. Present study will help to improve the theoretical research system of PV tracking bracket construction, irradiance modeling of moving bifacial modules, and intelligent tracking algorithms.

Evaluation of Horizontal Single‐Axis Solar Tracker Algorithms in Terms of Energy Production and Operational Performance

Horizontal single‐axis solar tracking systems with Astronomical tracking algorithm are commonly used in photovoltaic (PV) installations. However, different algorithms can increase the PV installation's performance without implementing new equipment or technologies. In this article, the performance of three tracking algorithms is compared to the Astronomical one. Two algorithms aim at optimizing the received irradiance focusing on the diffuse component. The third one, called Analytical, is presented as a new development in this study, defining the optimal inclination angle depending on all radiation components. The comparison focuses on different parameters like the in‐plane irradiance, DC power output from a monofacial PV system and operational aspects like the performed number of movements. High‐time‐resolution (1 min) simulations are performed with proprietary software taking into account several effects on the effective irradiance and power output estimation, such as shading effects or PV configuration. Eight locations with different climatic conditions are analyzed. All three algorithms derive in higher in‐plane irradiance and power output values than the Astronomical algorithm, although the gain depends on the climatic conditions. At locations with high diffuse fraction, the power output from the Analytical algorithm, which outperforms the others, can be up to 3% higher than the Astronomical one.

ПОВЫШЕНИЕ ЭФФЕКТИВНОСТИ ИСПОЛЬЗОВАНИЯ СОЛНЕЧНЫХ ПАНЕЛЕЙ

A method for controlling a two-axis solar tracker using an astronomical algorithm and a microcontroller is proposed. A practical solution is considered to achieve maximum efficiency of solar panels, which is associated with calculating the position of the sun, determining the desired an-gle for the solar tracker, reading the current angle of the tracker and adjusting its position

Implementasi Algoritma Jean Meeus dalam Penentuan Gerhana Bulan dan Matahari

This study aims to determine the implementation and accuracy of the Jean Meeus Algorithm in determining lunar and solar eclipses.This research is a qualitative research with a literature approach. The primary data source for this research is a book entitled Astronomical Algorithm by Jean Meeus. Meanwhile, secondary data is all information related to the Jean Meeus algorithm in determining eclipses obtained from various literature such as books, websites, encyclopedias, dictionaries, scientific articles, and other sources of information. The results of this study indicate that determining the eclipse time using the Jean Meeus algorithm involves seven stages of calculation namely; starting with determining the year the eclipse occurred, then determining the gamma value, JDE (Julian Day Ephemeris), the payoff value (k), the saros series, the reference time (To) and the Bessel Element value. The calculation of the Jean Meeus Algorithm is included in the tahkiki essential reckoning method because the calculation process involves astronomical data with very precise corrections for the motion of the Moon and the Sun, This method is also based on the heliocentric flow. In addition, the level of accuracy of Jean Meeus' calculations has a good match with NASA as a comparison, namely with results that are only 1 to 3 minutes apart and the average difference is only in seconds.

DEVELOPMENT OF ASTRO TIME ISLAMIC PRAYER SCHEDULE APPLICATION AND ALTITUDE CORRECTION TEST

The tool for calculating prayer times continues to develop. Likewise, there are several different formulas for calculating prayer times, both with the addition of altitude correction and without altitude correction. This article uses the prayer time formula which takes into account altitude corrections into an application called Islamic Astro Time which uses Matlab programming with solar data from the astronomical algorithms formula by Jean Meeus. This article is an experimental qualitative with descriptive analysis. This article finds that the calculation of prayer times in the Islamic Astro Time application using varying altitude levels results in different times. The difference in results starts from 2 minutes at a building height of 250 meters to more than 2 minutes depending on the level of height. The higher the position of the person praying, the greater the difference between the start of the prayer and the lower place. So that every Muslim who wants to pray must pay attention to the altitude correction factor with the sun's position approaching the horizon, namely the time of dawn, late dawn (ṭulū'), maghrib, and evening prayers.

Teaching with Code: Globular Cluster Distance Lab

Modern astronomy increasingly depends on computational thinking. Although some astronomy courses for undergraduates use computing, high school astronomy courses often have little computing. Created as a part of a research experience for teachers in astronomy and another in computer science, this project leverages robotic telescope images and astronomical algorithms to determine the distance to a star cluster using variable stellar photometry. Students investigate Python and Jupyter Notebook to analyze astronomical images to calculate the interstellar distance to a star cluster across the Milky Way. Students will learn how to write Python code that runs in a Jupyter Notebook such that the brightness of stars in an astronomical image can be determined. The real astronomical image data will be directly manipulated and analyzed by code the students create. Student project files and teacher solution files are provided. Code is open source, and materials are available for classroom use.

Кинематические свойства электротехнических комплексов с системой слежения за Солнцем, полученные методом полиномиальной аппроксимации небесных координат

The synthesis and study of any solar plants is associated with the need to identify regular features of the effector movement, the angular position of which is controlled in Euclidean space. This information can be obtained by processing data on the angular position of the Sun in predetermined geographical coordinates. However, any algorithm for calculating the solar position is time-localized, which means it cannot be used to uniformly analyze the annual and daily cycle of the Sun. To solve this problem, this research applies a new principle of processing calculation results, which is staged as follows. Using NREL SPA the astronomical algorithm, which is based on non-linear trigonometric equations, construct two-dimensional surfaces of azimuths of zenith angles. By approximating these surfaces with high-order polynomials and differentiating these polynomials in time, find azimuthal surfaces from zenith angular velocities, accelerations, and jerks. The calculated coefficients of the polynomials are tabulated for future use in evaluative calculations for structural and parametric synthesis of electrical systems for tracking the Sun in a given geographical location. To test the agreement with available local-time online algorithms, this research uses the MIDC SPA Calculator. Comparing the results of polynomial approximation with the output of this online calculator shows a good coincidence of the results and a low level of errors.

Performance evaluation of a multi-degree of freedom hybrid controlled dual axis solar tracking system

Solar energy represents a clean and sustainable energy resource for many countries around the world. A solar tracking system (STS) can significantly improve the collection of solar energy by reducing the solar incidence angle. The present research presents the design, modeling, and simulation of a two-axis STS with a hybrid controlled tracking system. The present hybrid control system implements a Multi-Degree of Freedom Simplified Universal Intelligent Proportional Integral Differential controller (MDOF SUI PID). The MDOF controller integrates an open-loop astronomical algorithm and a closed-loop strategy based on a simplified and intelligent controller. The impact of the hybrid control strategy using the MDOF SUI PID controller on the sun tracking system accuracy was evaluated in the present work. Modeling and simulation of the proposed control strategy were performed using the MATLAB/Simulink package. The results show a sun tracking pointing error of ±0.18° and a typical tracking accuracy of ±0.12°. The present hybrid STS provides a uniform Performance ratio of about 97% for a 60 W PV panel from sunrise to sunset.

A Principal Component Analysis of Vertical Temperature Profiles for Tracking Movements of Large Pelagic Fishes

Pop-up satellite archival tag (PSAT) technology that records depth, temperature, and light-level data has expanded the understanding of free-swimming behavior for numerous pelagic animals. Astronomical algorithms using these light-level data have allowed geolocation estimates of daily longitude and latitude. However, many pelagic animals have a crepuscular behavior pattern in which individuals are at depths below the photic layer during the day, thus precluding the use of traditional light-based movement algorithms for geolocation in such species as swordfish. A principal component analysis (PCA) of temperature profiles is described herein that utilizes depth and temperature data rather than light to estimate the horizontal movement between the initial location of tag release and transmission. PSAT data from swordfish (n=4), blue marlin (n=14), white marlin (n=2), and black marlin (n=1) were used to generate daily coordinate estimates. The marlin data provided sufficient light information to derive geolocation estimates using two light-based state space models, while the hydrographic PCA model was used to derive comparison estimates. Comparisons of the two model types show an average root mean square difference of 175.4 km demonstrating that the PCA model can be used to extract the movement of tagged swordfish and other pelagic species demonstrating crepuscular behavior. Integration of this PCA-based geolocation methods with both the best available estimates of the ocean temperature at the time of tag deployment and the existing light-based geolocation models would provide additional information on fine-scale movement of tagged fish.

THE DETERMINATION OF CHRISTIAN HOLIDAYS IN INDONESIA BY USING MEEUS ASTRONOMICAL

Astronomically, Easter falls on the first Sunday following the first full moon after the vernal equinox. In Indonesia, Christian holidays including Easter are regulated by the Ministry of Religious Affairs based on the recommendation of Indonesian Church Union (PGI) and Bishops Conference of Indonesia (KWI). This study objective is to formulate a simple time marker by using Meeus Astronomical Algorithm to determine Christian holidays in Indonesian Gregorian calendar. Another objective is to evaluate the Christian holidays on Indonesian calendar between 1960 and 2015. Finally, this study would also provide prediction for future Christian holidays. This study finds out that the Christian holidays on Indonesian calendar are proven as methodologically accurate. It indicates that Meeus Astronomical Algorithm can produce accurate calculation for determining Christian holidays in Indonesia in the future.
 KEY WORDS:Meeus astronomical algorithm, christian holidays, Indonesian calendar

Experimental Investigation of Multijunction Solar Cell Using Two Axis Solar Tracker

Solar cell is the most cost effective and simple device to harvest solar energy as compared to other systems. Many types of single junction solar cell are available in market but their main problem is low efficiency. This paper focuses on the performance investigation of high efficiency multijunction solar cell using two axis solar tracker. High solar concentration is needed for multijunction solar cell with accurate solar tracking to get maximum energy output. Solar tracker is based upon the astronomical algorithm of solar tracking. Tracking System consists of GPS module, AVR microcontroller, stepper motors with drive modules and some other accessories. The tracking system takes geographical location data from GPS to calculate sun position for tracking.

Experimental Investigation of Multijunction Solar Cell Using Two Axis Solar Tracker

Solar cell is the most cost effective and simple device to harvest solar energy as compared to other systems. Many types of single junction solar cell are available in market but their main problem is low efficiency. This paper focuses on the performance investigation of high efficiency multijunction solar cell using two axis solar tracker. High solar concentration is needed for multijunction solar cell with accurate solar tracking to get maximum energy output. Solar tracker is based upon the astronomical algorithm of solar tracking. Tracking System consists of GPS module, AVR microcontroller, stepper motors with drive modules and some other accessories. The tracking system takes geographical location data from GPS to calculate sun position for tracking.

Design, operation, and performance evaluation of a cable‐drawn dual‐axis solar tracker compared to a fixed‐tilted system

AbstractThis article discusses the design, operation, and performance evaluation of a unique cable‐operated 6.24 kWp commercial‐size solar tracking system called iPV dual‐axis tracker or iPV DAT with a position detector to gain the maximum power from the sunlight. Compared with other solar tracking systems, low cost, simplified hardware structure, and controlling algorithm are the advantages of this system. The operating method of the 6.24 kWp iPV DAT follow a simple pull and release of the steel cables connecting the corners of the PV module frame to the electric motors and directed by an electronic control system. The steel cables attached to the corners of the module frame also provide an extra stability in the event of high wind of up to 220 km/h. The accuracy of the tracking effect is managed by an astronomical algorithm that enables a full 360° azimuth rotation and altitude tilt of −40° to 40° (0 = horizontal). The controller algorithm also includes backtracking capability that allows optimization of ground cover ratio. Performance evaluation of the iPV DAT installed and operated in Taiwan for 12 months is compared with a fixed‐tilt PV system. An average electricity gain of 30.1% and performance ratio of 93% are realized using iPV DAT.

Astronomy Algorithm Simulation for Two Degrees of Freedom of Solar Tracking Mechanism Using Clanguage

Abstract This paper describes the use of an astronomical algorithm for two degrees of freedom of solar tracking mechanism with the result that the expected solar thermal collector panels always leads to the sun and solar energy is absorbed optimally. The movement triggers of the sun tracking mechanism is an astronomical algorithm that generates the azimuth and altitude values based on latitude, longitude, and time. This system does not use any sensor so that is more economical and can be applied anywhere. Simulations have been made using the C programming language with Dev-C + + IDE to test the accuracy of the azimuth and elevation values generated by astronomical algorithm used, and compared with the value produced by the U.S. Naval Observatory and Geoscience Australia. The location used is LIPI Bandung with latitude 10736′E and longitude 652′S at every hour from 06:00 to 18:00 on the first date of each month of 2013. Simulation results show that the value of the azimuth and elevation resulting approached two other reference values with maximum azimuth difference 0.51 degrees and the maximum altitude difference 0.49 degrees to data the U.S. Naval Observatory, and the maximum azimuth difference 0.52 degrees and the maximum altitude difference 0.50 degrees to the data Australia Geoscience. Based on this research, it is known that the azimuth and elevation values was generated by these algorithms can be applied to two degrees of freedom of solar tracking mechanism because its accuracy is close to two other reference values.

Open-source Cloud-based Energy Calculator/simulator

In this paper we will present a newly written energy calculator built as a project between CICESE and the State Energy Commission of Baja California. The system runs server side and is written in PHP and Python storing its data on a MySQL database. The user interface allows the user to input their geographic location, and electrical energy use history. The user can then choose from a virtual warehouse of photovoltaic systems offered by local installers. Using astronomical algorithms, and weather station data the system generates a list of solar intensity values and calculates the response of chosen photovoltaic. The final values calculated are the cost predictions for the next 20 years. Because of its open-source nature, then system can be easily expanded to include wind power systems, carbon production, and ever gas and water usage. The primary user for this system is the general public with hopes that they will become educated on their energy use, and the potential effects of new photovoltaic installations.

An Innovative Design of the Automatic Solar Tracking Control Scheme

A double-axis solar tracking system based on horizontal coordinate is adopted. A method of combining the sun trajectory tracking and light intensity sensor is proposed in this tracking system. Detection results of light intensity sensor were used to determine weather situation, control the start -stop of the tracking system. The sun trajectory was calculated by astronomical algorithms to determine the solar orientation. Different interval times were set in different time periods to improve the tracking accuracy. It enhances solar radiation, improves the power generation efficiency of photovoltaic systems and reduces the cost of photovoltaic power generation. This system is simple and easy to achieve. It has lower cost and reliable performance. It can be used in large-scale photovoltaic power plant projects.

Astronomical algorithms for automated analysis of tissue protein expression in breast cancer

Background:High-throughput evaluation of tissue biomarkers in oncology has been greatly accelerated by the widespread use of tissue microarrays (TMAs) and immunohistochemistry. Although TMAs have the potential to facilitate protein expression profiling on a scale to rival experiments of tumour transcriptomes, the bottleneck and imprecision of manually scoring TMAs has impeded progress.Methods:We report image analysis algorithms adapted from astronomy for the precise automated analysis of IHC in all subcellular compartments. The power of this technique is demonstrated using over 2000 breast tumours and comparing quantitative automated scores against manual assessment by pathologists.Results:All continuous automated scores showed good correlation with their corresponding ordinal manual scores. For oestrogen receptor (ER), the correlation was 0.82, P<0.0001, for BCL2 0.72, P<0.0001 and for HER2 0.62, P<0.0001. Automated scores showed excellent concordance with manual scores for the unsupervised assignment of cases to ‘positive' or ‘negative' categories with agreement rates of up to 96%.Conclusion:The adaptation of astronomical algorithms coupled with their application to large annotated study cohorts, constitutes a powerful tool for the realisation of the enormous potential of digital pathology.

접시형 태양열 발전시스템에서 사용하는 여러 가지 형태의 태양추적시스템의 태양추적성능 분석

Sun tracking system is the most important subsystem in parabolic dish type solar thermal power plant, since it determines the amount of thermal energy to be collected, thus affects the efficiency of solar thermal power plant most significantly. Various types of sun tracking systems are currently used. Among them, use of photo sensors to located the sun(which is called sensor type) and use of astronomical algorithm to compute the sun position(which is called program type) are two of the mostly used methods. Recently some uses CCD sensor, like CCD camera, which is called image processing type sun tracking system. This work is concerned with the analysis of sun tracking performance of various types of sun tracking systems currently used in the parabolic dish type solar thermal power plant. We first developed a sun tracking error measurement system. Then, we evaluate the performance of five different types of sun tracking systems, sensor type, program type, hybrid type(use of sensor and computed sun position simultaneously), tracking error compensated program type and image processing type. Experimentally obtained data shows that the tracking error compensated program type sun tracking system is very effective and could provide a good sun tracking performance. Also the data obtained shows that the performance of sensor type sun tracking system is being affected by the cloud significantly, while the performance of a program type sun tracking system is being affected by the sun tracking system's mechanical and installation errors very much. Finally image processing type sun tracking system can provide accurate sun tracking performance, but costs more and requires more computational time.

Tracking the stars, Sun, and Moon to connect with the universe

We describe the theory, design, and construction of simple electromechanical devices that automatically and continually track celestial objects. As Earth rotates and revolves, a star tracker always points at a star or other objects fixed to the celestial sphere, such as the center of the Milky Way galaxy. A planet tracker can fixate on any celestial object including the planets, the Sun, or the Moon. A sidereal clock mechanism drives the star tracker, and software that encodes astronomical algorithms controls an inexpensive robot that drives the planet tracker. The star tracker acts like a gyroscope, rigidly oriented in space, despite Earth’s motion. Both trackers indicate the passing of time just like clocks and calendars. The resulting lecture, hallway, or museum displays promote awareness of and excitement about our place in the universe.