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  Uppercaseonly text (as many letters as A 's)   aa  alphabetic text (as many letters as a 's)   CCC  Constellation 3letter 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 Dayinmonth numeral   DD.dd  Dayinmonth 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   vvv  Volume number   W  A letter indicating one of the 4 directions (N, S, E or W)   WW  Letters indicating one of the 8 directions (NE, NW, SE, SW)   xxxx.x  Offset along xaxis 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 yaxis from some reference position in any kind of unit (pixel, arcsec, mm, etc)   {NGCIC}  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. {QG} 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 {ABCDE} . To specify a upper or lowercase letter in the range A to E, one can write {A..Ea..e} (modified in November 2006) 

Format Example Remarks  
 Running number  
NNN... HD  
 Declination zone  
+DD NNN BD28 2411   Sk69 72 Not Sk7269  
 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  
 Galactic coordinates  
LLL.ℓ+BB.b+VVV HVC  GLLL.ℓ+BB.b PN  
 Field  
FFFNNNN LP hyphens are recommended   ESO  FFFFNNNNN GSC  
 Constellation  
CCC YYYY Nova  
 Year or Date  
YYYYA SN 1987A  YYYYaa SN 1993aj  YYMMDDA GRB 991216 γray burst  YYYY MMM DDA GB 1979 Nov 05A  
• NN+DD Sk 7269 instead of Sk69 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