Position Of The Sun Research Articles

Automatic solar tracking system: a review pertaining to advancements and challenges in the current scenario

Abstract An automatic solar tracking system is an approach for optimizing the generation of solar power and modifying the angles and direction of a solar panel by considering changes in the position and path of the sun. The performance status of an automatic solar tracking system depends on various factors, including its design, location, and maintenance or repairs. The solar energy from the sun that the Earth intercepts is approximately 1.8 × 1011 MW, which is thousands of times greater than the intensity at which the Earth now uses all other commercially available energy sources combined. Currently, research into automatic solar trackers is on the rise, as solar energy is abundant in nature, but its use in a highly efficient way is still lacking. This paper provides a detailed literature review and highlights some key advancements and challenges associated with state-of-the-art automatic solar tracking systems. The performance of the dual-axis photovoltaic tracking system outperforms that of the stationary systems by more than 27% based on the overall system efficiency. Under diverse weather conditions, the efficiency of the scheduled-based solar tracking systems was enhanced by 4.2% compared with that of the light-dependent resistor-based solar trackers.

Resonant Forcing by Solar Declination of Rossby Waves at the Tropopause and Implications in Extreme Precipitation Events and Heat Waves—Part 2: Case Studies, Projections in the Context of Climate Change

Based on the properties of Rossby waves at the tropopause resonantly forced by solar declination in harmonic modes, which was the subject of a first article, case studies of heatwaves and extreme precipitation events are presented. They clearly demonstrate that extreme events only form under specific patterns of the amplitude of the speed of modulated airflows of Rossby waves at the tropopause, in particular period ranges. This remains true even if extreme events appear as compound events where chaos and timing are crucial. Extreme events are favored when modulated cold and warm airflows result in a dual cyclone-anticyclone system, i.e., the association of two joint vortices of opposite signs. They reverse over a period of the dominant harmonic mode in spatial and temporal coherence with the modulated airflow speed pattern. This key role could result from a transfer of humid/dry air between the two vortices during the inversion of the dual system. Finally, focusing on the two period ranges 17.1–34.2 and 8.56–17.1 days corresponding to 1/16- and 1/32-year period harmonic modes, projections of the amplitude of wind speed at 250 mb, geopotential height at 500 mb, ground air temperature, and precipitation rate are performed by extrapolating their amplitude observed from January 1979 to March 2024. Projected amplitudes are regionalized on a global scale for warmest and coldest half-years, referring to extratropical latitudes. Causal relationships are established between the projected amplitudes of modulated airflow speed and those of ground air temperature and precipitation rate, whether they increase or decrease. The increase in the amplitude of modulated airflow speed of polar vortices induces their latitudinal extension. This produces a tightening of Rossby waves embedded in the polar and subtropical jet streams. In the context of climate change, this has the effect of increasing the efficiency of the resonant forcing of Rossby waves from the solar declination, the optimum of which is located at mid-latitudes. Hence the increased or decreased vulnerability to heatwaves or extreme precipitation events of some regions. Europe and western Asia are particularly affected, which is due to increased activity of the Arctic polar vortex between longitudes 20° W and 40° E. This is likely a consequence of melting ice and changing albedo, which appears to amplify the amplitude of variation in the period range 17.1–34.2 days of poleward circulation at the tropopause of the Arctic polar cell.

Design and Implementation of a Dual-Axis Solar Tracking System with IoT-Enhanced Monitoring Using Arduino

The position of the sun varies over the day and with the seasons, making it difficult for conventional fixed solar panel systems to achieve optimum energy production. By reorienting the panels to face the sun, solar tracking systems solve this problem. This study suggests a dual-axis solar tracker system that continuously adjusts the panels to stay perpendicular to sunlight in order to maximize energy capture. The system uses sensors to monitor the sun's elevation and azimuth angles. Light sensors, motor controllers, microcontrollers, control algorithms, and an Internet of Things (IoT) monitoring system are some of the system's essential parts. The microprocessor determines the ideal angles for panel alignment based on the location of the sun as detected by the light sensors. The motor driver then adjusts the panels appropriately. The sun's position is accurately and smoothly tracked using dual-axis tracking systems, which employ sensors to detect solar position and actuators controlled by sophisticated algorithms to adjust the panels accordingly. Real-time parameter monitoring of the solar panel is done using an IoT-enabled webpage. The study's findings show that the dual-axis solar tracker system performs noticeably better in terms of energy capture efficiency than fixed installations, especially in areas with high solar incidence angles and fluctuating sunshine.

Sun Declination and Distribution of Natural Beam Irradiance on Earth

Sun Declination and Distribution of Natural Beam Irradiance on Earth

Auto-luminescence in seedlings: possible indicators for the gravimetric tide?

Germinating seedlings emit light in the visible range spontaneously, and these emissions are related to metabolism and reactive-oxygen species (ROS) processes. Several series of germination tests had such biological auto-luminescence (BAL) recorded in controlled conditions, fostering applications for the non-invasive, real-time evaluation of a seedling’s germinability and vigor when submitted to chemical and/or physical perturbations. However, long-term analysis of the BAL time-series of control samples conducted in different locations around the globe reveals that their BAL signals (and thus their metabolism) appear to follow the local gravimetric tide (g-tide) time profile. This indicates that the small daily and monthly variations in gravity acceleration due to the relative positioning of the Sun and Moon with respect to the Earth’s surface influence these signals. The gravimetric tide is a natural phenomenon that affects all things, fluid or solid, and is an uncontrollable variable in normal laboratory settings on Earth’s crust. All things on Earth have evolved under these pervasive cycles, with periods ranging from ∼12.2 h up to 28 d, which correspond to the Moon cycle. Tide-like cycles occur in living beings of different types, from the simplest bacteria to the most complex human beings, and we speculate that water availability at the molecular level could be a significant physical factor in modulating bio-activity by enabling protein folding and all metabolic pathways that require a synchronized organization to adapt to external environmental conditions. In this study, we summarize published results of a seedling’s BAL with cycle patterns resembling the g-tide in Limeira/BR, Prague/CZ, Leiden/NL, and Hamamatsu/JP and discuss the possible implications of this phenomenon for chronobiological studies.

Solar flare observations with the Radio Neutrino Observatory Greenland (RNO-G)

The Radio Neutrino Observatory – Greenland (RNO-G) seeks discovery of ultra-high energy neutrinos from the cosmos through their interactions in ice. The science program extends beyond particle astrophysics to include radioglaciology and, as we show herein, solar observations, as well. Currently seven of 35 planned radio-receiver stations (24 antennas/station) are operational. These stations are sensitive to impulsive radio signals with frequencies between 80 and 700 MHz and feature a neutrino trigger threshold for recording data close to the thermal floor. RNO-G can also trigger on elevated signals from the Sun, resulting in nanosecond resolution time-domain flare data; such temporal resolution is significantly shorter than from most dedicated solar observatories. In addition to possible RNO-G solar flare polarization measurements, the Sun also represents an extremely useful above-surface calibration source.Using RNO-G data recorded during the summers of 2022 and 2023, we find signal excesses during solar flares reported by the solar-observing Callisto network and also in coincidence with ∼2/3 of the brightest excesses recorded by the SWAVES satellite. These observed flares are characterized by significant time-domain impulsivity. Using the known position of the Sun, the flare sample is used to calibrate the RNO-G absolute pointing on the radio signal arrival direction to sub-degree resolution. We thus establish the Sun as a regularly observed astronomical calibration source to provide the accurate absolute pointing required for neutrino astronomy.

Perancangan Tata Udara Menggunakan Metode Cooling Load Tempreture Difference (CLTD) Pada Studi Kasus Proyek X

This research is related to the design of air conditioning using the Cooling Load Temperature Difference (CLTD) method in the case study of Project X. One of the methods used is the Cooling Load Temperature Difference (CLTD) method. This method considers factors such as wet-bulb temperature, dry-bulb temperature, and air velocity to calculate the room cooling load. This research applies the CLTD method to a case study project in Jakarta with an air conditioning system in office buildings. This case study provides an example of the practical application of the CLTD method that is beneficial for practitioners in the field of air conditioning engineering. To implement the CLTD method, data from field studies such as room conditions, temperature, and humidity of the room and environment are needed. Next, calculations are made using the CLTD formula adjusted to the position of the sun in each room. The CLTD calculation results show that the highest sensible load is in the Boardroom, while the highest latent load is in the Conference Room. The design of the cooling system with the CLTD method shows optimal results and meets the requirements. The AC capacity calculated accurately and considering K4L factors results in an efficient, safe, and environmentally friendly cooling system.

Influence of the Sun on the night side of the Earth

Solar radiation breaks hydrogen bonds between water molecules, which prevents their self-organization and destroys water clusters. This may be accounted for by the influence of muons which are generated in the upper atmosphere by the solar wind. Muon flux is anisotropic and changes direction depending on the position of the Sun in the sky. For this reason, the rate of hydrolysis of triethyl phosphite in acetonitrile depends on geometric shape of the reaction solution, its position in space and changes during the day. For example, in three 5 mm NMR-tubes directed North-South, East-West and Vertically the distributions of the rates of this reaction are always different in the daytime. At noon, when the Sun is at its zenith, the rates are considerably higher in the horizontal tubes, and at sunrise and sunset when the Sun shines along the East-West line the rate is higher in the vertical tube. One might assume that at night when the Sun irradiates the opposite side of the Earth, this phenomenon should disappear, and the reaction rates should be the same in all directions. However, it turned out that at midnight the distribution of hydrolysis rates in multidirectional NMR-tubes is the same as at noon. This may indicate that on the night side of the Earth the influence of the Sun is inducing the appearance of some radiation vertically from underground. This phenomenon requires detailed study in different places on the Earth.

ВЛИЯНИЕ ВЫСОТЫ СЪЕМКИ И ЗЕНИТНОГО УГЛА СОЛНЦА НА ВЕГЕТАЦИОННЫЕ ИНДЕКСЫ ПШЕНИЦЫ ПО ДАННЫМ БПЛА

The purpose of the study is to assess the influence of the survey altitude and the solar zenith angle on the color and spectral vegetation indices (VI) of wheat obtained from survey data from a UAV in the arid climate of Transbaikalia. Tasks: to perform multi-altitude aerial photography of the experimental field at different positions of the Sun; to calculate the VI and conduct a comparative statistical analysis of the obtained data. The study was carried out at the training and reclamation site of the Buryat State Agricultural Academy named after V.R. Filippov in the suburbs of Ulan-Ude on August 12, 2023. An experimental field with an area of 600 m2 is sown with Selenga wheat variety, bred for the arid conditions of the Republic of Buryatia. The field is divided into 4 strips with different levels of irrigation and rainfed option. Each lane is represented by 3 NPK experiments in triplicate. The assessment of dependencies was carried out within one variant, divided into 20 identical segments in order to maintain sample homogeneity. The survey of a section of the experimental field was carried out at altitudes from 40 to 200 m at solar zenith angles from 36.5 to 74.5° using UAVs equipped with RGB and multispectral cameras. Color and spectral VIs were calculated. The groups of color VIs ExG-ExGR-GLI and ExR-NDI-VARI and spectral VIs NDVI-RVI and SAVI-DVI are mutually interchangeable due to their high pairwise correlation (more than 0.99). The results of the Wilcoxon test generally showed the similarity of the average VI values of GLI, ExG, ExGR, as well as NDVI and SAVI during the period from 14:10 to 17:30, which is optimal for surveying. The average VI va¬lues decrease with height and differ significantly, so the surveying altitude should be taken into account when monitoring the condition of crops. It is necessary to develop the scientific foundations of unmanned agricultural monitoring in various climatic conditions.

Prototype solar dome designed to function as a solar calendar

ABSTRACT The experiment aimed to create a prototype of a calendar dome that shows the days of the year using solar light passing through specific holes in the dome’s covering. Specific openings are placed on the dome to allow sunlight pass through daily all year round. Clear skies allow radiation to pass through and illuminate months plate. For more precise calculations, lenses can also be placed in the dome body to regulate and calibrate the location and orientation of reflected light. The light is then directed onto specific mirrors, which then reflect it onto a central control plate functioning as a fixed date reader in the center of the room. As bold characters are reversed and placed between the mirror and the central control plate, they display the exact day and time of the year. The date and time will be clearly shown on the control plate as a silhouette. To make it all done, the authors assessed the position, azimuth, latitude, and elevation angle of the sun to accurately determine the direction of solar radiation. This guarantees the precise and effective creation of the Solar Calendar Dome Prototype.

Dark matter in the Milky Way: Measurements up to 3 kpc from the Galactic plane above the Sun

We probe the gravitational force perpendicular to the Galactic plane at the position of the Sun based on a sample of red giants, with measurements taken from the DR3 Gaia catalogue. Measurements far out of the Galactic plane up to 3.5 kpc allow us to determine directly the total mass density, where dark matter is dominant and the stellar and gas densities are very low. In a complementary way, we have also used a new determination of the local baryonic mass density to help determine the density of dark matter in the Galactic plane at the solar position. For the local mass density of dark matter, we obtained $ dm $0.0008\,M$_ $ = 0.486 pm 0.030 Gev\ $. For the flattening of the gravitational potential of the dark halo, it is $q_ phi,h For its density, $q_ rho,h $=0.781pm 0.055.

Determining the influence of seasonal tilt angle on the efficiency of fixed solar photovoltaic modules

The object of this study is photovoltaic modules with different seasonal tilt angles at different geographical latitudes. The average annual efficiency of photovoltaic modules with different seasonal angles set at different geographical latitudes has been determined as the annual weighted average value of the cosine of the angle of incidence of solar rays on the plane of the photovoltaic module. The influence of seasonal tilt angles of photovoltaic modules at different geographical latitudes on their average annual efficiency was analyzed. Approximate values of the seasonal tilt angles of photovoltaic modules at different geographic latitudes take values that differ from the geographic latitude value by plus 15° for the winter period and minus 15° for the summer period. Modeling the average annual efficiency of photovoltaic modules depending on the seasonal tilt angles at different geographical latitudes made it possible to obtain refined values of the seasonal tilt angles of photovoltaic modules. Thus, at the latitude of 0°, 10°, 20°, 30°, 40°, 50°, and 60°, the tilt angle of photovoltaic modules for the winter period will be 14.8°, 24.6°, 34.5°. 44.4°, 54.1°, 63.6°, and 73°, respectively, and for summer ‒ minus 14.5°, minus 4.6°, 5°, 15.1°, 25.1°, 34.9°, and 44.7°. Dependences were obtained for determining the seasonal tilt angles of photovoltaic modules depending on the value of geographic latitude. The difference in the average annual efficiency of photovoltaic modules, which are installed at seasonal angles, and photovoltaic modules, which track the position of the Sun in the vertical plane, is 0.4 %. The results could be used as a basis for evaluating the efficiency of photovoltaic modules when determining the seasonal tilt angle at different geographic latitudes

Investigation of factors affecting the reflectance spectra of GEO Satellites

Geostationary orbit (GEO) satellites have extensive application in fields like communications and navigation due to their stationary properties. Using additional methods to identify and characterise GEO satellites is crucial for enhancing cataloguing capabilities and verifying their operation status. Reflectance spectroscopy is a promising technique for characterising satellites, but a deeper understanding of the primary factors influencing satellite reflectance spectra is required. So we carried out slitless spectroscopic observations on six GEO satellites using the 80 cm high-precision telescope of the Purple Mountain Observatory located in Yaoan, Yunnan. Reflectance spectra and by-product light curves were then obtained after necessary spectral extraction and correction procedures. Our experiment and observation lasted over ten months, and this paper utilizes a subset of data with high Signal-to-Noise Ratio(SNR). Based on the reflectance spectral data obtained, we discovered that: The dominant factor impacting the reflectance spectra is the Multi-layer insulation(MLI) on the surface of three-axis stabilized GEO satellites. Reflectance spectral trends of GEO satellites do not change significantly over the course of a night with changes in the sun-satellite-observatory phase angle. The normalised reflectance spectral trends remain unchanged despite variations in the solar declination. The aforementioned findings establish a strong basis for utilising reflectance spectra to recognise and classify non-cooperative GEO satellites.

Using astronomy to analyse the van Gogh drawing ‘Bank of the Rhone’

This paper presents an astronomical analysis of the van Gogh drawing ‘Bank of the Rhone’ to determine the possible dates of its creation. By examining the position of the sun depicted in the drawing and comparing it with the actual sunset positions at the location in Arles, France, a range of dates is derived that differs from the accepted historical dating of the work. The study demonstrates the potential of using interdisciplinary approaches that combine art and astronomy to gain new insights into artistic works. The analysis also serves as an engaging exercise for students to explore the intersection of science and art.

Farmers’ use of Indigenous knowledge on climate change adaptation across farming systems and agroecological zones of Sierra Leone

The qualitative analysis of farmers’ use of Indigenous knowledge on climate change adaptation across farming systems and agroecological zones of Sierra Leone was conducted using a combination of interpretive phenomenological analysis, Focus Group Discussions, and participant observation, which was analyzed with a qualitative interpretative approach. Farmers respond to climate change through the use of wind and cloud patterns, animal and bird behavior, moon shape, and position of the sun to predict changes in temperature, intensity, drying up of rivers, and frequency of rainfall, as well as the incidence of pests and diseases. Other Indigenous knowledge used by farmers were rotational grazing, migration, crop-livestock integration, and the use of manure for composting with herbal and biological treatment for disease management. The study recommended that in the current context of climate change, the promotion of adaptation strategies should explore the interdependency of different knowledge systems and knowledge hybridity in agriculture.

An Asymmetric Galactic Stellar Disk Traced by OB-type Stars from LAMOST DR7

Using 9943 OB-type stars from LAMOST DR7 in the solar neighborhood, we fit the vertical stellar density profile with the model including a single exponential distribution at different positions (R, Φ). The distributions of the scale heights and scale length show that the young disk traced by the OB-type stars is not axisymmetric. The scale length decreases versus the azimuthal angle Φ, i.e., from 1.14−0.19+0.30 kpc with Φ = − 3° to 0.77−0.06+0.08 kpc with Φ = 9°. Meanwhile we find signal of non-symmetry in the distribution of the scale height of the north and south of the disk plane. The scale height in the north side shows signal of flaring of the disk, while that of the south disk stays almost constant around h s = 130 pc. The distribution of the displacement of the disk plane Z 0 also shows variance versus the azimuthal angle Φ, which displays significant differences with the warp model constrained by the Cepheid stars. We also test different values for the position of the Sun, and the distance between the Sun and the Galactic center affects the scale heights and the displacement of the disk significantly, but that does not change our conclusion that the disk is not axisymmetric.

Resonant Forcing by Solar Declination of Rossby Waves at the Tropopause and Implications in Extreme Events, Precipitation, and Heat Waves—Part 1: Theory

The purpose of this first article is to provide a physical basis for atmospheric Rossby waves at the tropopause to clarify their properties and improve our knowledge of their role in the genesis of extreme precipitation and heat waves. By analogy with the oceanic Rossby waves, the role played by the pycnocline in ocean Rossby waves is replaced here by the interface between the polar jet and the ascending air column at the meeting of the polar and Ferrel cell circulation or between the subtropical jet and the descending air column at the meeting of the Ferrel and Hadley cell circulation. In both cases, the Rossby waves are suitable for being resonantly forced in harmonic modes by tuning their natural period to the forcing period. Here, the forcing period is one year as a result of the variation in insolation due to solar declination. A search for cause-and-effect relationships is performed from the joint representation of the amplitude and phase of (1) the velocity of the cold or warm modulated airflows at 250 mb resulting from Rossby waves, (2) the geopotential height at 500 mb, and (3) the precipitation rate or ground air temperature. This is for the dominant harmonic mode whose period can be 1/16, 1/32, or 1/64 year, which reflects the intra-seasonal variations in the rising and falling air columns at the meeting of the polar, Ferrel, and Hadley cell circulation. Harmonics determine the duration of blocking. Two case studies referring to extreme cold and heat waves are presented. Dual cyclone–anticyclone systems seem to favor extreme events. They are formed by two joint vortices of opposite signs reversing over a period, concomitantly with the involved modulated airflows at the tropopause. A second article will be oriented toward (1) the examination of different case studies in order to ascertain the common characteristics of Rossby wave patterns leading to extreme events and (2) a map of the globe revealing future trends in the occurrence of extreme events.

Transformation of Prayer Time Schedules: from A Static-Passive to A Dynamic-Variative Perspective

Prayer times are extremely important for Muslims, as they serve as a guide for the beginning of prayer times. However, there are still people who do not fully understand the impact of changes in the position of the Sun, which causes the start of prayer times to change daily. Additionally, some people still use perpetual prayer time schedules. Although they use the term "perpetual," in reality, prayer time schedules are not everlasting, as they cannot be used over long periods. This research is a library study with a phenomenological-astronomical approach. The results of this study show that prayer times change every day. Someone who believes that the start of Maghrib prayer is always at 18:00 WIB and the start of Fajr prayer is always at 04:30 WIB may find that on some days, their prayer or fasting is invalid, as the start of Maghrib prayer may occur between 18:01 and 18:08 WIB and the start of Fajr prayer may occur between 04:31 and 04:34 WIB. These changes can serve as an understanding for the community that the correctness of prayer time schedules is not static-passive but dynamic-variable. This means that the start of prayer times each day and year is not always the same as the following days and years, and the changes vary. Therefore, this study provides a scientific guide for the community to better understand and be cautious in using prayer time schedules, considering that the beginning of prayer times determines the validity of a Muslim's prayer.

Solar Panel Sun-Rays Tracking and Cleaning System for Improvement in Power Efficiency

There is an increasing need to reduce greenhouse gas emissions and find more environmentally friendly ways to power the planet. An estimated 4 billion years will pass before the sun stops shining, making it a renewable natural power source. A sustainable method of generating electricity from the sun's energy is offered by solar power systems. In comparison with single axis solar tracker, a dual axis solar tracker tracks the sun at every instance hereby increasing the efficiency by 30-35%. In this system we have a solar panel which tracks the position of the sun and always try to remain perpendicular to sun rays. It will track the sun in all four directions i.e east-west and north-south. This paper focus more on Design of Dual tracking system, which includes installation of GPS and RTC system, stored energy usage for application , periodic cleaning in order to maintain efficiency of panel and comparative analysis of stored energy. Alternative, less expensive options have been suggested because the solar tracking equipment is expensive to manufacture.The goal of this effort is to create a solar dual tracking system model that includes solar panel cleaning as well.

A CNN-LSTM model using elliptical constraints for temporally consistent sun position estimation

More accurate sun position estimation could transform the design and operation of solar power systems, weather forecasting services, and outdoor augmented reality systems. Although several image-based approaches to sun position estimation have been proposed, their performance is significantly affected by momentary disruptions in cloud cover because they use only a single image as input. This study proposes a deep learning-based sun position estimation system that leverages spatial, temporal, and geometric features to accurately regress sun positions even when the sun is partially or entirely occluded. In the proposed approach, spatial features are extracted from an input image sequence by applying a separate Resnet-based convolution network to each frame. To ensure that the temporal changes in the brightness distribution across frames are considered, the spatial features are concatenated and passed on to a stack of LSTM layers prior to regressing the final sun position. The proposed network is also trained with elliptical (geometric) constraints to ensure that predicted sun positions are consistent with the natural elliptical path of the sun in the sky. The proposed approach's performance was evaluated on the Sirta and Laval datasets along with a custom dataset, and an R2 Score of 0.98 was achieved, which is at least 0.1 higher than that of previous approaches. The proposed approach is capable of identifying the position of the sun even when occluded and was employed in a novel sky imaging system consisting of only a camera and fisheye lens in place of a complex array of sensors.