The angular diameter of an object as seen from a given position is the diameter measured as an angle. It can be calculated using the formula Diameter is an AAA (authentication, authorization and accounting) protocol for applications such as network access or IP mobility. ...

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in which δ is the angular diameter, and d and D are the diameter of and the distance to the object, expressed in the same units. When D is much larger than d, δ may be approximated by the formula δ = d / D-, in which the result is in radians. The radian is a unit of plane angle. ...

In astronomy the size of objects in the sky is often measured in terms of their angular diameter as seen from Earth, rather than their actual size. A giant Hubble mosaic of the Crab Nebula. ... Earth (IPA: , often referred to as the Earth, Terra, or Planet Earth) is the third planet in the solar system in terms of distance from the Sun, and the fifth largest. ...

The angular diameter of Earth's orbit around the Sun, from a distance of one parsec, is 2" (two arcseconds). Stellar parallax motion The parsec (symbol pc) is a unit of length used in astronomy. ... A second of arc or arcsecond is a unit of angular measurement which comprises one-sixtieth of an arcminute, or 1/3600 of a degree of arc or 1/1296000 ≈ 7. ...

The angular diameter of the Sun, from a distance of one light-year, is 0.03", of the Earth 0.0003". A light-year, symbol ly, is the distance light travels in one year: exactly 9. ...

This table shows the angular sizes of the most important Solar System bodies as seen from the Earth. Major features of the Solar System (not to scale): The Sun, the eight planets, the asteroid belt containing the dwarf planet Ceres, outermost there is the dwarf planet Pluto (the dwarf planet Eris not shown), and a comet. ...

• Alpha Centauri A: ca. 0.007"
• Sirius: ca. 0.007"

This meaning the angular diameter of the Sun is ca. 250,000 that of Sirius (it has twice the diameter and the distance is 500,000 times as much; the Sun is 10,000,000,000 times as bright, corresponding to an angular diameter ratio of 100,000, so Sirius is roughly 6 times as bright per unit solid angle). The Sun is the star of our solar system. ... Bulk composition of the Moons mantle and crust estimated, weight percent Oxygen 42. ... Adjective Venusian or (rarely) Cytherean (*min temperature refers to cloud tops only) Atmospheric characteristics Atmospheric pressure 9. ... Adjective Jovian Atmospheric characteristics Atmospheric pressure 70 kPa Hydrogen ~86% Helium ~14% Methane 0. ... Adjective Saturnian Atmospheric characteristics Atmospheric pressure 140 kPa Hydrogen >93% Helium >5% Methane 0. ... Note: This article contains special characters. ... Adjective Uranian Atmospheric characteristics Atmospheric pressure 120 kPa (at the cloud level) Hydrogen 83% Helium 15% Methane 1. ... Adjective Neptunian Atmospheric characteristics Surface pressure ≫100 MPa Hydrogen - H2 80% ±3. ... Alpha Centauri A is a star of the star system Alpha Centauri. ... Sirius (α CMa / α Canis Majoris / Alpha Canis Majoris) is the brightest star in the night-time sky, with a visual apparent magnitude of −1. ... A solid angle is the three dimensional analog of the ordinary angle. ...

The angular diameter of the Sun is also ca. 250,000 that of Alpha Centauri A (it has the same diameter and the distance is 250,000 times as much; the Sun is 40,000,000,000 times as bright, corresponding to an angular diameter ratio of 200,000, so Alpha Centauri A is a little brighter per unit solid angle).

The angular diameter of the Sun is about the same as that of the Moon (the diameter is 400 times as large and the distance also; the Sun is 200,000-500,000 times as bright as the full Moon (figures vary), corresponding to an angular diameter ratio of 450-700, so a celestial body with a diameter of 2.5-4" and the same brightness per unit solid angle would have the same brightness as the full Moon).

See also

• Angular resolution
• Apparent size