The **angular diameter** or **apparent size** of an object as seen from a given position is the “visual diameter” of the object measured as an angle. In the vision sciences it is called the visual angle. The visual diameter is the diameter of the perspective projection of the object on a plane through its centre that is perpendicular to the viewing direction. Because of foreshortening, it may be quite different from the actual physical diameter for an object that is seen under an angle. For a disk-shaped object at a large distance, the visual and actual diameters are the same.

Read more about Angular Diameter: Formulas, Use in Astronomy, Non-circular Objects, Defect of Illumination

### Other articles related to "angular diameter, diameters, diameter, angular":

Haven: Call Of The King - Planets Trivia - Ferven

... Exarco (1°47'

... Exarco (1°47'

**angular diameter**) far left, Ferra Nequam (2°**angular diameter**) center side by side, Auria (2°**angular diameter**) not too far to right ...Solar Eclipses On Pluto

... Charon presents an

... Charon presents an

**angular diameter**of roughly 4 degrees of arc as seen from the surface of Pluto the Sun appears much smaller, only 40 arcseconds ... There are large uncertainties in the**diameters**of the three smaller moons, and as a result their apparent**diameters**(as seen from Pluto) are also uncertain ... However, it is known that Nix's**angular diameter**is 3–9 minutes of arc, while Hydra's is 2–7 minutes ...Standard Ruler

... By measuring its apparent

... By measuring its apparent

**angular diameter**in the sky, one can determine its distance from Earth ... An object with a known**diameter**would look smaller at farther distances, the**angular**size being proportional to the inverse of the distance to the object ... The distance to the object can therefore be estimated by knowing its actual**diameter**and measuring its**angular**size ...Mutual Planetary Transits and Occultations

1243 UTC, when Venus near superior conjunction (with an

1243 UTC, when Venus near superior conjunction (with an

**angular diameter**of 10.6") will transit in front of Jupiter (with an**angular diameter**of 30.9") however, this will ... When the nearer object has a larger**angular diameter**than the farther object, thus covering it completely, the event is not a transit but an occultation ...**Angular Diameter**- Defect of Illumination

... Defect of illumination is the maximum

**angular**width of the unilluminated part of a celestial body seen by a given observer ...

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