Related papers: The Sun's position in the sky
With only five photographs of the Sun at different dates we show that the mass of Sun can be calculated by using a telescope, a camera, and the Kepler's third law. With these photographs we are able to calculate the distance between Sun and…
The occlusion of the sun by clouds is one of the primary sources of uncertainties in solar power generation, and is a factor that affects the wide-spread use of solar power as a primary energy source. Real-time forecasting of cloud movement…
We explore new opportunities for solar physics that could be realized by future missions providing sustained observations from vantage points away from the Sun-Earth line. These include observations from the far side of the Sun, at high…
Observations of the Sun in the visible spectral range belong to standard measurements obtained by instruments both on the ground and in the space. Nowadays, both nearly continuous full-disc observations with medium resolution and dedicated…
The Sun provides a standard reference against which we compare the chemical abundances found anywhere else in the Universe. Nevertheless, there is not a unique 'solar' composition, since the chemical abundances found in the solar interior,…
The high quality data provided by helioseismology, solar neutrino flux measurements, spectral determination of solar abundances, nuclear reactions rates coefficients among other experimental data, leads to the highly accurate prediction of…
A method to measure the seeing from video made during drift-scan solar transits is proposed. The limb of the Sun is projected over a regular grid evenly spaced. The temporal dispersion of the time intervals among the contacts between solar…
Earthshine is sunlight that has been reflected from the dayside Earth onto the dark side of the Moon and back again to Earth. In recent times, there has been renewed interest in ground-based visible and near-infrared measurements of…
We investigate the effects of atmospheric dispersion on observations of the Sun at the ever-higher spatial resolutions afforded by increased apertures and improved techniques. The problems induced by atmospheric refraction are particularly…
A simple closed-form expression for the number of days between the winter solstice and the latest sunrise is derived. Formulas for the summer solstice and the sunset are derived as well. These approximate formulas make it easy to see the…
We proposed an analytical model for the calculus of illumination time of the Earth for any time of year and any latitude, this model assumes the obliquity of the ecliptic as constant, the light beams as parallels, the Earth as spherical,…
Direct Sun light absorption by trace gases can be used to quantify them and investigate atmospheric chemistry. In such experiments, the main optical apparatus is often a grating or a Fourier transform spectrometer. A solar tracker based on…
I present a novel macroscopic wave geometric effect of the sunbeam occurring when the sunbeam directional (shadow by a bar) angle c velocity is observed on the earth surface and a sunbeam global positioning device with a needle at the…
The physical principles and the mathematical structure involved in deriving an analytical representation of the internal structure of the sun are discussed. For a two-parameter family of a non-linear matter density distribution, the run of…
The kinematics of the Solar zenith passage on the Earth was shown as a simple harmonic motion. This analytical model used the uniform circular motion to describe the Earth's rotation relative to its axis and relative to the Sun, also this…
The magnetic cycle of the Sun, as manifested in the cyclic appearance of sunspots, significantly influences our space environment and space-based technologies by generating what is now termed as space weather. Long-term variation in the…
Beyond the Sun-Earth line, spacecraft equipped with various solar telescopes are intended to be deployed at several different vantage points in the heliosphere to carry out coordinated, multi-view observations of the Sun and its dynamic…
We present a method for measuring the Sun's motion using the proper motions of Galactic halo star streams. The method relies on the fact that the motion of the stars perpendicular to a stream from a low-mass progenitor is close to zero when…
It is well known that the length and orientation of a shadow cast by a vertical gnomon depends on the time of the day and on the season of the year. But it also depends on the latitude of the site of observation. During the equinoxes, the…
We numerically integrate the equations of motion of the Sun in Galactocentric Cartesian rectangular coordinates for -4.5 Gyr <= t <= 0 in Newtonian mechanics with two different models for the Cold Dark Matter (CDM) halo, in MOdified…