Real astronomy and dated history, with sources. Documented traditions and folklore. Modern lunar astrology · symbolic, not predictive.

Chart basics · Advanced

Second of arc

Also called arcsecond, ″

One sixtieth of an arcminute, 1/3600 of a degree.

Arcseconds matter for checking an ephemeris, not for reading a chart. The site's positions agree with NASA JPL's within a few arcseconds for the planets and about ten for the Moon, far finer than the minute a chart displays.

Kind: Calculation, Astronomy
Tradition: Astronomy
In this site’s birth chart: not used

Swiss Ephemeris documentation (Astrodienst): house systems, nodes and calculation conventions (opens in a new tab) technical

Written for Cool Moon Facts in its own words. An astrology source documents what astrologers believe or practise; it does not establish that astrology works.

All terms · Your birth chart

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Second of arc

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Second of arc

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