arcsecond
Noun: A unit of angular measurement equal to one sixtieth (1/60) of an arcminute, and thus one three-thousand-six-hundredth (1/3600) of a degree. It is used in astronomy, cartography, and other fields requiring precise measurement of very small angles.
The term "arcsecond" is a technical term used almost exclusively in scientific and technical contexts, particularly astronomy, to describe the apparent size or separation of celestial objects or the precision of telescope pointing. * Astronomers measure the angular distance between stars in arcseconds. * The planet's apparent diameter is only a few arcseconds. * The telescope's resolution is better than one arcsecond.
- Parallax Measurement: In astronomy, the distance to nearby stars is often calculated using stellar parallax, measured in arcseconds. A star with a parallax of one arcsecond is defined to be one parsec away.
- Seeing Conditions: The quality of astronomical "seeing," which refers to the blurring effect of Earth's atmosphere, is often described by the size of a star's image in arcseconds.
- Second of arc: A synonymous phrase for arcsecond.
- Arcminute (noun): A unit of angular measurement equal to 1/60 of a degree, or 60 arcseconds.
- Degree (noun): A unit of angular measurement; there are 360 degrees in a full circle, 60 arcminutes in a degree, and 3600 arcseconds in a degree.
- Second of arc
The word "arcsecond" is a compound of "arc," referring to a segment of a circle, and "second," which in this context is a division (the second division) of a degree, following the "minute" (the first division). It is crucial to distinguish it from a unit of time. In the provided reference context, "2 minutes and 45 seconds south" refers to arcminutes and arcseconds of latitude, not units of time.
- a 60th part of a minute of arc
- the treasure is 2 minutes and 45 seconds south of here