From 40e5a5811c6ffce9b0974e93cdd927cbcf60c157 Mon Sep 17 00:00:00 2001 From: Joe Hunkeler Date: Tue, 11 Aug 2015 16:51:37 -0400 Subject: Repatch (from linux) of OSX IRAF --- pkg/xtools/skywcs/doc/ccsystems.hlp | 134 ++++++++++++++++++++++++++++++++++++ 1 file changed, 134 insertions(+) create mode 100644 pkg/xtools/skywcs/doc/ccsystems.hlp (limited to 'pkg/xtools/skywcs/doc/ccsystems.hlp') diff --git a/pkg/xtools/skywcs/doc/ccsystems.hlp b/pkg/xtools/skywcs/doc/ccsystems.hlp new file mode 100644 index 00000000..63a2fde6 --- /dev/null +++ b/pkg/xtools/skywcs/doc/ccsystems.hlp @@ -0,0 +1,134 @@ +.help ccsystems Mar00 Skywcs +.ih +NAME +ccsystems -- list and describe the supported sky coordinate systems +.ih +USAGE +help ccsystems + +.ih +SKY COORDINATE SYSTEMS + +The sky package supports the equatorial ("fk4", "fk4-noe", "fk5", "icrs"), +ecliptic, galactic, and supergalactic celestial coordinate systems. In most +cases and unless otherwise noted users can input their coordinates in +any one of these systems as long as they specify the coordinate system +correctly. + +Considerable flexibility is permitted in how the coordinate systems are +specified, e.g. J2000.0, j2000.0, 2000.0, fk5, fk5 J2000, and fk5 2000.0 +all specify the mean place post-IAU 1976 or FK5 system. Missing equinox and +epoch fields assume reasonable defaults. In most cases the +systems of most interest to users are "icrs", "j2000", and "b1950" +which stand for the ICRS J2000.0, FK5 J2000.0 and FK4 B1950.0 celestial +coordinate systems respectively. The full set of options are listed below: + +.ls equinox [epoch] +The equatorial mean place post-IAU 1976 (FK5) system if equinox is a +Julian epoch, e.g. J2000.0 or 2000.0, or the equatorial mean place +pre-IAU 1976 system (FK4) if equinox is a Besselian epoch, e.g. B1950.0 +or 1950.0. Julian equinoxes are prefixed by a J or j, Besselian equinoxes +by a B or b. Equinoxes without the J / j or B / b prefix are treated as +Besselian epochs if they are < 1984.0, Julian epochs if they are >= 1984.0. +Epoch is the epoch of the observation and may be a Julian +epoch, a Besselian epoch, or a Julian date. Julian epochs +are prefixed by a J or j, Besselian epochs by a B or b. +Epochs without the J / j or B / b prefix default to the epoch type of +equinox if the epoch value <= 3000.0, otherwise epoch is interpreted as +a Julian date. If undefined epoch defaults to equinox. +.le +.ls icrs [equinox] [epoch] +The International Celestial Reference System where equinox is +a Julian or Besselian epoch e.g. J2000.0 or B1980.0. +Equinoxes without the J / j or B / b prefix are treated as Julian epochs. +The default value of equinox is J2000.0. +Epoch is a Besselian epoch, a Julian epoch, or a Julian date. +Julian epochs are prefixed by a J or j, Besselian epochs by a B or b. +Epochs without the J / j or B / b prefix default to Julian epochs +if the epoch value <= 3000.0, otherwise epoch is interpreted as +a Julian date. If undefined epoch defaults to equinox. +.le +.ls fk5 [equinox] [epoch] +The equatorial mean place post-IAU 1976 (FK5) system where equinox is +a Julian or Besselian epoch e.g. J2000.0 or B1980.0. +Equinoxes without the J / j or B / b prefix are treated as Julian epochs. +The default value of equinox is J2000.0. +Epoch is a Besselian epoch, a Julian epoch, or a Julian date. +Julian epochs are prefixed by a J or j, Besselian epochs by a B or b. +Epochs without the J / j or B / b prefix default to Julian epochs +if the epoch value <= 3000.0, otherwise epoch is interpreted as +a Julian date. If undefined epoch defaults to equinox. +.le +.ls fk4 [equinox] [epoch] +The equatorial mean place pre-IAU 1976 (FK4) system where equinox is a +Besselian or Julian epoch e.g. B1950.0 or J2000.0, +and epoch is the Besselian epoch, the Julian epoch, or the Julian date of the +observation. +Equinoxes without the J / j or B / b prefix are treated +as Besselian epochs. The default value of equinox is B1950.0. Epoch +is a Besselian epoch, a Julian epoch, or a Julian date. +Julian epochs are prefixed by a J or j, Besselian epochs by a B or b. +Epochs without the J / j or B / b prefix default to Besselian epochs +if the epoch value <= 3000.0, otherwise epoch is interpreted as +a Julian date. If undefined epoch defaults to equinox. +.le +.ls noefk4 [equinox] [epoch] +The equatorial mean place pre-IAU 1976 (FK4) system but without the E-terms +where equinox is a Besselian or Julian epoch e.g. B1950.0 or J2000.0, +and epoch is the Besselian epoch, the Julian epoch, or the Julian date of the +observation. +Equinoxes without the J / j or B / b prefix are treated +as Besselian epochs. The default value of equinox is B1950.0. +Epoch is a Besselian epoch, a Julian epoch, or a Julian date. +Julian epochs are prefixed by a J or j, Besselian epochs by a B or b. +Epochs without the J / j or B / b prefix default to Besselian epochs +if the epoch value <= 3000.0, otherwise epoch is interpreted as +a Julian day. If undefined epoch defaults to equinox. +.le +.ls apparent epoch +The equatorial geocentric apparent place post-IAU 1976 system where +epoch is the epoch of observation. +Epoch is a Besselian epoch, a Julian epoch or a Julian date. +Julian epochs are prefixed by a J or j, Besselian epochs by a B or b. +Epochs without the J / j or B / b prefix default to Besselian +epochs if the epoch value < 1984.0, Julian epochs +if the epoch value <= 3000.0, otherwise epoch is interpreted as +a Julian date. +.le +.ls ecliptic epoch +The ecliptic coordinate system where epoch is the epoch of observation. +Epoch is a Besselian epoch, a Julian epoch, or a Julian date. +Julian epochs are prefixed by a J or j, Besselian epochs by a B or b. +Epochs without the J / j or B / b prefix default to Besselian epochs +if the epoch values < 1984.0, Julian epochs +if the epoch value <= 3000.0, otherwise epoch is interpreted as +a Julian day. +.le +.ls galactic [epoch] +The IAU 1958 galactic coordinate system. +Epoch is a Besselian epoch, a Julian epoch or a Julian date. +Julian epochs are prefixed by a J or j, Besselian epochs by a B or b. +Epochs without the J / j or B / b prefix default to Besselian +epochs if the epoch value < 1984.0, Julian epochs +if the epoch value <= 3000.0, otherwise epoch is interpreted as +a Julian date. The default value of epoch is B1950.0. +.le +.ls supergalactic [epoch] +The deVaucouleurs supergalactic coordinate system. +Epoch is a Besselian epoch, a Julian epoch or a Julian date. +Julian epochs are prefixed by a J or j, Besselian epochs by a B or b. +Epochs without the J / j or B / b prefix default to Besselian +epochs if the epoch value < 1984.0, Julian epochs +if the epoch value <= 3000.0, otherwise epoch is interpreted as +a Julian date. The default value of epoch is B1950.0. +.le + +Fields enclosed in [] are optional with the defaults as described. The epoch +field for the "icrs" , "fk5", "galactic", and "supergalactic" coordinate +systems is only used if the input coordinates are in the equatorial fk4, +noefk4, fk5, or icrs systems and proper motions are used to transform from +coordinate system to another. + +.ih +SEE ALSO +.endhelp -- cgit