Symbol Explanation Default Limits
RAh Part of the right ascension expressed in hours [0,24[ RAm Part of the right ascension expressed in minutes [0,60[ RAs Part of the right ascension expressed in seconds [0,60[ RAdeg Right ascension expressed in decimal degrees (Alternative: RAhms could be envisaged for a right ascension expressed in sexagesimal with no embedded blanks and leading zeroes, RAbhms for sexagesimal values with embedded blanks. Such extensions would however require special interpretation by FITS readers. ) [0,360[ RArad Right ascension expressed in radians [0,2π[ RAsec Right ascension expressed in seconds [0,86400[ DE- Sign of declination [+-] DEd Part of the declination expressed in degrees [0,90] DEm Part of the declination expressed in arc minutes [0,60[ DEs Part of the declination expressed in arc seconds [0,60[ DEdeg Declination expressed in decimal degrees (Alternative: DEdms could be envisaged for a declination expressed in sexagesimal with no embedded blanks and leading zeroes, DEbdms for sexagesimal values with embedded blanks; questions similar to the RAhms note have to be addressed. ) [–90,+90] DErad Declination expressed in radians [–π/2,+π/2] DEsec Declination expressed in arcsec [–324000,+324000] PosErr Position mean error >=0 dRA dDE Difference in Right Ascension or Declination oRA oDE Offset from a reference position in R.A. or Dec. ELON ecliptic longitude [0,360[ ELAT ecliptic latitude [–90,+90] GLON galactic longitude [0,360[ GLAT galactic latitude [–90,+90
Epoch Epoch — write Ep-1900 for a year with 1900 offset plx Parallax pmRA Proper motion in Right Ascension pmDE Proper motion in Declination pmX Proper motion along X direction
Seq a Sequential number used e.g. to number the objects Name the main name of an object or feature
Diam Diameter – or MajDiam and MinDiam >=0 Axis Half Diameter – also MajAxis and MinAxis >=0 PA Position Angle, normally North to East [0,360[ Rad Radius >=0 HRV Heliocentric Radial velocity RVel Radial velocity Sep Separation (anglular or linear) >=0 SpType Spectral type MType Morphological type Vmag Magnitude (apparent) in V filter VMag Absolute Magnitude in V filter Kmag Magnitude (apparent) in K filter ...
Sp+Index Spectral index (α in relation S(ν) = να) Sp-Index Spectral index (α in relation S(ν) = ν–α)
BibCode The 19-digit bibcode Text Free-format text like list of authors, titles...
Remember that a label is always a single word: it cannot contain any embedded blank or space. Other characters are in principle accepted, e.g. parentheses or other punctuation signs, with the following restrictions:
Some commonly used labels are presented in
Some comments on the labels defined in
A parameter has frequently associated values, and we have adopted
the rule of association with the one-letter-underscore prefix:
if a column is obviously associated to another one — typically
mean errors or uncertainty flags — we use one of the
underscore prefixes listed in
Usual mathematical functions may be specified in the label,
with parentheses or a dot; for instance, the logarithm of the effective
temperature could be labelled log(Te) or log.Te.
/srv/httpd/Pages/doc/catstd-3.3.htx
.Y Year part (in order to avoid any ambiguity,
the year should include all 4 digits)
.M Month name or number in range [1⋅⋅⋅12]
.D Day number in month
(2 digits, range [1⋅⋅⋅31]) or
year (3 digits, range [1⋅⋅⋅366])
.h Hour (range [0⋅⋅⋅24[)
.m Minutes (range [0⋅⋅⋅60[))
.s Seconds (range [0⋅⋅⋅60[))
.d Degrees (range [0⋅⋅⋅360[)
For instance, the various components of an observation date and
time can be labelled Obs.Y, Obs.Y, Obs.M,
Obs.D, Obs.h, Obs.m.
Symbol Explanation Default Limits
a_label aperture used for
parameter label >=0
B_label for an upper bound (maximal value)
on parameter label
b_label for a lower bound (minimal value)
on parameter label
D_label for a difference (Δ)
on parameter label (e.g. (O-C)
d_label for a number of degrees of freedom
or for number of digits on
parameter label >0
E_label mean error (upper limit)
on parameter label >=0
e_label mean error (σ)
on parameter label >=0
f_label flag
on parameter label
L_label Likelihood
on parameter label
l_label limit flag
on parameter label [<>]
m_label multiplicity index
on parameter label to resolve ambiguities
n_label note (remark)
on parameter label
o_label number of observations
on parameter label >=0
q_label quality
on parameter label
r_label reference (source) for parameter label
s_label dispersion (σ)
on parameter label (the σ of a mean of N values
is asymptotically equal to the dispersion divided by
sqrt(N)) >=0
u_label uncertainty flag
on parameter label [ :]
w_label weight of parameter label >=0
x_label unit in which parameter label is
expressed