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An arcsecond (second of arc), represented by the symbol ,[1] is a unit of angle used in mathematics and astronomy. An arcsecond is 1/60th of an arcminute (minute of arc),[2] which in turn is 1/60th of a degree.[3] Therefore, an arcsecond is equal to 1/3600th of a degree,[2] meaning that there are 360 × 60 × 60 = 1,296,000 arcseconds in a full circle.
1m @ 200km
One milliarcsecond (mas) is a thousandth (1/1000th) of an arcsecond. So there are 1,296,000,000 milliarcseconds in a full circle. The red supergiant stars Antares, Betelgeuse,[4] Mu Cephei, VV Cephei A, and VY Canis Majoris all have angular diameters (apparent sizes in the sky) of more than 10 milliarcseconds, when seen from Earth.
1mm @ 200km
Related pages
[change | change source]References
[change | change source]- ↑ "List of Geometry and Trigonometry Symbols". Math Vault. 2025-08-07. Retrieved 2025-08-07.
- ↑ 2.0 2.1 Weisstein, Eric W. "Arc Second". mathworld.wolfram.com. Archived from the original on 2025-08-07. Retrieved 2025-08-07.
- ↑ Weisstein, Eric W. "Arc Minute". mathworld.wolfram.com. Archived from the original on 2025-08-07. Retrieved 2025-08-07.
- ↑ "Archived copy" (PDF). Archived from the original (PDF) on 2025-08-07. Retrieved 2025-08-07.
{{cite web}}: CS1 maint: archived copy as title (link)
