This document details the symbols used in formatting the sequence of astronomical designations, and provide examples of use (and misuse).
Symbols | Meaning |
---|---|
- | dash or hyphen |
+ | sign (+ or -) |
+BB.b | Degrees of galactic latitude (as many decimals as lowercase b 's) |
+DDd | Degrees of declination (as many decimals as lowercase d 's) |
AA | Uppercase-only text (as many letters as A 's) |
aa | alphabetic text (as many letters as a 's) |
CCC | iConstellation 3-letter abbreviation (Official list) |
B | Introduces the coordinates based on B1950 Equinox |
D | Tens of degrees of declination |
DD | May be degrees of declination (in principle preceded by a sign), or Day-in-month numeral |
DD.dd | Day-in-month and fractions of day (as many decimals as lowercase d 's) |
DDD.d | Right ascension expressed in decimal degrees (as many decimals as lowercase d 's) |
FF | Field number (as many digits as F 's) |
G | introduces the Galactic coordinates (optional) |
HH.hh | Hours of right ascension (as many decimals as lowercase h 's) |
J | Introduces the coordinates based on J2000 Equinox (and ICRS) |
LLL.l | Degrees of galactic longitude (as many decimals as lowercase l 's) |
M | May be units of minute (range 0 to 9) if followed by SS , m or a decimal point; represents tens of minutes (range 0 to 5) otherwise |
MM | May be minutes (of hour or degree), or month numeral |
MMm | Minutes of right ascension or declination, (as many decimals as lowercase m 's) |
NNN | Ordinal number (as many digits as N 's) |
NN.N | Ordinal number with inserted numbers (as many digits as N 's) |
RRR | Roman numeral (as many R 's as maximal length) |
S | May be units of seconds (range 0 to 9) if followed by s or a decimal point; represents tens of seconds (range 0 to 5) otherwise |
SS.s | Seconds of right ascension or declination, (as many decimals as lowercase s 's) |
VVV | Velocity in km/s (as many digits as V 's) |
VVV.v | Velocity in km/s with decimals |
Z | Redshift (as many digits as Z 's) |
Z.z | Redshift with decimals |
vvv | Volume number |
W | A letter indicating one of the 4 directions (N, S, E or W) |
WW | Letters indicating one of the 4 directions (NE, NW, SE, SW) |
xxxx.x | Offset along x-axis from some reference position in any kind of unit (pixel, arcsec, mm, etc) |
YYYY | Year (YY when 2 digits, YYYY when 4 digits) |
yyyy.y | Offset along y-axis from some reference position in any kind of unit (pixel, arcsec, mm, etc) |
{NGC|IC} | One of the alternatives listed between the curly braces
{
... }
and separated by the vertical bars
|
— here either the text
NGC or the text
IC
. An empty text is possible as e.g.
{Q|G|}
means either the letter
Q , the letter
G
, or nothing. Note: it is possible to use 2 dots .. to indicate a range of letter, e.g. {A..E} is equivalent to {A|B|C|D|E} . To specify a upper- or lower-case letter in the range A to E, one can write {A..E|a..e} (modified in November 2006) |
Format | Example | Remarks |
---|---|---|
Running number | ||
NNN... | HD | |
Declination zone | ||
+DD NNN | BD-28 2411 | |
Sk-69 72 | Not Sk72-69 | |
Equatorial coordinates | ||
HHMM+DD | PKS | |
HHMM+DDd | PKS | |
BHHMM+DD | PSR | |
BHHMM+DDd | PKS | |
JHHMM+DDMM | PSR | |
PKS | ||
HHMMm+DDMM | IRAS | Point Source Cat. |
HHMM.m+DDMM | 1E | (IPC) |
HHMMSS+DDMMSS | 6C | |
HHMMSS.s+DDMMSS | 1E | (HRI) |
BHHMMSS.s+DDMMSS | 6C | |
JHHMMSS.ss+DDMMSS.s | SDSS | |
Galactic coordinates | ||
LLL.ℓ+BB.b+VVV | HVC | |
GLLL.ℓ+BB.b | PN | |
Field | ||
FFF-NNNN | LP | hyphens are recommended |
ESO | ||
FFFF-NNNNN | GSC | |
Constellation | ||
CCC YYYY | Nova | |
Year or Date | ||
YYYYA | SN 1987A | |
YYYYaa | SN 1993aj | |
YYMMDDA | GRB 991216 | γ-ray burst |
YYYY MMM DDA | GB 1979 Nov 05A |
Format | Remarks |
---|---|
NN+DD | Sk 72-69 instead of Sk-69 72 |
HHNDA | Pawsey (1955P1), First use of the coordinates in the format |
+DD.NN | as in OB to OZ (1967S1) |
+DNN.N | any combination where the point does not mean a decimal point or the declination is in tens of degrees |
HH.MM.m.NN | GN by Neckel (1985NV), any combination where the point does not mean a decimal point |
HHMM+DD.N | where the point does not mean a decimal point (e.g. Glazar) |
HHMM+DDM | truncating to tens of arc minutes in declination is strongly discouraged, use +DDd or +DD.d instead. |
HHMM+DDdd | Don't use hundredths of degrees, but the sexagesimal division +DDMM |
MMSS+MMSS | Do not omit the leading HH and DD |