Basic unit type
Time units may be second (s), hour (h: 3600 s), day (d: 86400 s), Julian year (a, yr: 365.25 d), Julian century (cy: 36525 d), or empty (i.e., dimensionless) for ISO-8601 format
Coordinate units may be angular (degrees, radians, hours, arcmins, arcsecs), linear (meters, km, mm, AUs, parsecs, kpc, Mpc, lightyears), or empty (i.e., dimensionless)
Angular coordinate units may be degrees, radians, hours, arcmins, arcsecs
Position angles may be counted from North (through East), (positive) X (to positive Y), or (positive) Y (to positive X) axis
Velocity units are a posUnitType / velTimeType; the latter may be second, day, hour, year (a or yr), century, but not empty
Spectral units may be frequency (Hz, kHz, MHz, GHz), wavelength (meters, mm, micron, nm, Angstrom), or energy (eV, keV, MeV, GeV, TeV)
The actual time scale used: TT, TAI, UTC, TDB, etc.
Terrestrial Time; the basis for ephmerides
Obsolete synonym for TT
Ephemeris Time; predecessor of, and continuous with, TT
Barycentric Ephemeris Time:the independent variable in planetay ephemerides; time at the solar system barycenter synchronous with TT on an annual basis; often called TDB
Barycentric Dynamic Time: time at the solar system barycenter synchronous with TT on an annual basis; often confused with TEB
Terrestrial Coordinate Time
Barycentric Coordinate Time; runs slower than TDB but is consistent with physical constants
International Atomic Time; runs 32.184 s behind TT
Synonym for TAI
Coordinated Universal Time; currently (2004) runs 34 leapseconds behind TAI
Local Siderial Time; only for ground-based observations; note that the second is shorter
Only to be used for simulations in conjunction with a relocatable spatial frame
Position angles are doubles and include optionally a unit attribute (default deg) and a reference attribute (default X)
Substitution group for absoluteTimeType component of astronTimeType
ISO8601 time; note: only a limited subset of ISO 8601 is allowed: yyyy-mm-ddThh:mm:ss.sss...
IDREF to an ISO8601 time
JD time
IDREF to a JD time
MJD time (=JD - 2400000.5)
IDREF to an MJD time
A relocatable time origin for simulations
Substitution group: Relative time is elapsed time relative to the absolute reference time component
Actual elapsed time offset
IDREF to the elapsed relative time part of a AstronTime
astronTime is the generalized astronomical time type and consists of two or three elements: TimeScale, optional relative time offset, and an absolute time (ISO8601 or a decimal JD or MJD; or it may be an IDREF to one of those three)
For vector coordinates we need arrays of doubles
A vector of 2 doubles
A vector of 3 doubles
A vector of 4 doubles
A vector of 9 doubles
The head element for the CoordinateValue substitution group
Substitution group for a scalar coordinate value
double
IDREF to a Value
Substitution group for a scalar coordinate error
double
IDREF to an Error
Substitution group for a scalar coordinate resolution
double
IDREF to a Resolution
Substitution group for a scalar coordinate size
double
IDREF to a Size
Substitution group for a scalar coordinate pixel size
double
IDREF to a Pixel Size
Abstract coordinate type; a concrete Coordinate consists of a Value, Error, Resolution, Size, and PixSize
Generic scalar coordinate type
Single CError, CResolution, CSize, CPixSize elements indicate definite values; pairs indicate ranges
Time coordinate type
Single CError, CResolution, CSize, CPixSize elements indicate definite values; pairs indicate ranges
Consists of a Size (2 doubles) and optional position angle element
Substitution group for a 2-D coordinate value
double vector
IDREF to a Value2
Substitution group for a 2-D coordinate error
2 doubles Error element
size2Type Error element
2x2 matrix Error element
IDREF to an Error2
Substitution group for a 2-D coordinate resolution
2 doubles Resolution element
size2Type Resolution element
2x2 matrix Resolution element
IDREF to a Resolution2
Substitution group for a 2-D coordinate size
2 doubles Size element
size2Type Size element
2x2 matrix Size element
IDREF to a Size2
Substitution group for a 2-D coordinate pixel size
2 doubles PixSize element
size2Type PixSize element
2x2 matrix PixSize element
IDREF to a PixSize2
Generic 2-D coordinate type
Single CError2, CResolution2, CSize2, CPixSize2 elements indicate definite values; pairs indicate ranges
Consists of a Size (3 doubles) and optional position angle element
Substitution group for a 3-D coordinate value
Vector of 3 doubles
IDREF to a Value3
Substitution group for a 3-D coordinate error
3 doubles Error element
size3Type Error element
3x3 matrix Error element
IDREF to an Error3
Substitution group for a 3-D coordinate resolution
3 doubles Resoltuion element
size3Type Resolution element
3x3 matrix Resoltuion element
IDREF to a Resolution3
Substitution group for a 3-D coordinate size
3 doubles Size element
size3Type Size element
3x3 matrix Size element
IDREF to a Size3
Substitution group for a 3-D coordinate pixel size
3 doubles PixSize element
size3Type PixSize element
3x3 matrix PixSize element
IDREF to a PixSize3
Generic 3-D coordinate type
Single CError3, CResolution3, CSize3, CPixSize3 elements indicate definite values; pairs indicate ranges
Coordinate substitution group
Generic scalar coordinate element
Generic string coordinate element
Generic coordinate element for pixels
Position coordinate substitution group
1-D Position coordinate
2-D Position coordinate
3-D Position coordinate
Velocity coordinate substitution group
1-D Velocity coordinate
2-D Velocity coordinate
3-D Velocity coordinate
Specifies a FITS file and optionally a specific HDU by HDU number or HDU name
Refers coordinate components to specific columns in the FITS file HDU
The column name for the coordinate value; comma-separated if multi-dimensional
The column name for the coordinate error; comma-separated if multi-dimensional
The column name for the coordinate resolution; comma-separated if multi-dimensional
The column name for the coordinate size; comma-separated if multi-dimensional
The column name for the coordinate pixel size; comma-separated if multi-dimensional
Coordinate references to a specific FITS file
The generic coordsType
The astronomical (STC) coordsType
Some or all coordinate values may be given in file
The pixel coordinates type
Head element of Coords group (not abstract)
The coordinate element consists either of a coordinate file or a sequence of time element, spatial coordinate element, velocity element, and redshift element; the spatial and velocity elements may be scalar or vector; it needs to refer to a coordinate system
Contains pixel coordinates