Description of the Formats

This document details the symbols used in formatting the sequence of astronomical designations, and provide examples of use (and misuse).

Contents:


1  Inventory of the formats

 | 
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 | Constellation 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 | | 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 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)| |


2  Typical formats (usual or recommended)

 |
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 || |
| 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 || |


3  Misleading formats (obsolete or confusing)

 
• 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

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