B.1.11 Coords

Functions for angle transformations and manipulations. In particular, methods for translating between radians and HH:MM:SS.S or DDD:MM:SS.S type sexagesimal representations are provided.

DEGREE

The size of one degree in radians.

HOUR

The size of one hour of right ascension in radians.

ARC_MINUTE

The size of one arcminute in radians.

ARC_SECOND

The size of one arcsecond in radians.

radiansToDms( rad )

Converts an angle in radians to a formatted degrees:minutes:seconds string. No fractional part of the seconds field is given.

radiansToDms( rad, secFig )

Converts an angle in radians to a formatted degrees:minutes:seconds string with a given number of decimal places in the seconds field.

radiansToHms( rad )

Converts an angle in radians to a formatted hours:minutes:seconds string. No fractional part of the seconds field is given.

radiansToHms( rad, secFig )

Converts an angle in radians to a formatted hours:minutes:seconds string with a given number of decimal places in the seconds field.

dmsToRadians( dms )

Converts a formatted degrees:minutes:seconds string to an angle in radians. Delimiters may be colon, space, characters dm[s], or some others. Additional spaces and leading +/- are permitted.

hmsToRadians( hms )

Converts a formatted hours:minutes:seconds string to an angle in radians. Delimiters may be colon, space, characters hm[s], or some others. Additional spaces and leading +/- are permitted.

dmsToRadians( deg, min, sec )

Converts degrees, minutes, seconds to an angle in radians.

In conversions of this type, one has to be careful to get the sign right in converting angles which are between 0 and -1 degrees. This routine uses the sign bit of the deg argument, taking care to distinguish between +0 and -0 (their internal representations are different for floating point values). It is illegal for the min or sec arguments to be negative.

hmsToRadians( hour, min, sec )

Converts hours, minutes, seconds to an angle in radians.

In conversions of this type, one has to be careful to get the sign right in converting angles which are between 0 and -1 hours. This routine uses the sign bit of the hour argument, taking care to distinguish between +0 and -0 (their internal representations are different for floating point values).

skyDistance( ra1, dec1, ra2, dec2 )

Calculates the separation (distance around a great circle) of two points on the sky.

skyDistanceDegrees( ra1, dec1, ra2, dec2 )

Calculates the separation (distance around a great circle) of two points on the sky in degrees.

hoursToRadians( hours )

Converts hours to radians.

degreesToRadians( deg )

Converts degrees to radians.

radiansToDegrees( rad )

Converts radians to degrees.

raFK4toFK5( raFK4, decFK4 )

Converts a B1950.0 FK4 position to J2000.0 FK5 at an epoch of B1950.0 yielding Right Ascension. This assumes zero proper motion in the FK5 frame.

decFK4toFK5( raFK4, decFK4 )

Converts a B1950.0 FK4 position to J2000.0 FK5 at an epoch of B1950.0 yielding Declination This assumes zero proper motion in the FK5 frame.

raFK5toFK4( raFK5, decFK5 )

Converts a J2000.0 FK5 position to B1950.0 FK4 at an epoch of B1950.0 yielding Declination. This assumes zero proper motion, parallax and radial velocity in the FK5 frame.

decFK5toFK4( raFK5, decFK5 )

Converts a J2000.0 FK5 position to B1950.0 FK4 at an epoch of B1950.0 yielding Declination. This assumes zero proper motion, parallax and radial velocity in the FK5 frame.

raFK4toFK5( raFK4, decFK4, bepoch )

Converts a B1950.0 FK4 position to J2000.0 FK5 yielding Right Ascension. This assumes zero proper motion in the FK5 frame. The bepoch parameter is the epoch at which the position in the FK4 frame was determined.

decFK4toFK5( raFK4, decFK4, bepoch )

Converts a B1950.0 FK4 position to J2000.0 FK5 yielding Declination. This assumes zero proper motion in the FK5 frame. The bepoch parameter is the epoch at which the position in the FK4 frame was determined.

raFK5toFK4( raFK5, decFK5, bepoch )

Converts a J2000.0 FK5 position to B1950.0 FK4 yielding Declination. This assumes zero proper motion, parallax and radial velocity in the FK5 frame.

decFK5toFK4( raFK5, decFK5, bepoch )

Converts a J2000.0 FK5 position to B1950.0 FK4 yielding Declination. This assumes zero proper motion, parallax and radial velocity in the FK5 frame.