Block, Siteadmin, SkipCaptcha, Upload, Automoderated users, delete, edit, Moderators, move, protect, rollback, Administrators
27,336
edits
Changes
Jump to navigation
Jump to search
mLine 15:
Line 15: − +
Reverted edits by Jeepers (talk) to last revision by Sunda62
<math>\,\!s \approx \frac {180 \times 3600}{p \times \pi}</math>
<math>\,\!s \approx \frac {180 \times 3600}{p \times \pi}</math>
where pi is measured in seconds of arc.
where p is measured in seconds of arc.
The cotangent of one second (1/3600 of a degree) of arc is approximately 206,264.81. No parallax angle for any star will be larger than one second. Therefore astronomers initially defined a unit of stellar distance, the ''parsec'' (symbol pc), from this relationship. One parsec is the distance corresponding to a parallax angle of one second of arc. Hence:
The cotangent of one second (1/3600 of a degree) of arc is approximately 206,264.81. No parallax angle for any star will be larger than one second. Therefore astronomers initially defined a unit of stellar distance, the ''parsec'' (symbol pc), from this relationship. One parsec is the distance corresponding to a parallax angle of one second of arc. Hence: