NGC description of deepsky objects



In order to describe the visual appearance of deep sky objects in detail a set of "NGC description codes" was developed and inserted in the "New General Catalog" of John Dreyer. A (complex) combination of below description codes can be used describing a deep sky object.


 
Ab..............about                 n..............north 
alm.............almost                neb............nebula 
am..............among                 nf.............north following 
app.............appended              np.............north preceding 
att.............attached              nr.............near 
b...............brighter              N..............Nucleus, or to a
                                                     Nucleus 
be..............between               p..............pretty (before
                                                     F,B,L,S) 
biN.............binuclear             p..............preceding 
bn..............brightest towards     pg.............pretty gradually 
                the north side        pm.............pretty much 
bs..............brightest towards     ps.............pretty suddenly 
                the south side        P..............poor 
bp..............brightest towards     quad...........quadrilateral 
                the preceding side    quar...........quartile 
bf..............brightest towards     r..............resolvable 
                the following side                   (mottled,not resolved) 
B...............bright                rr.............partially relolved,
c...............considerably                         some stars seen 
ch..............chevelure             rrr............well resolved, clearly
co..............coarse, coarsely                     consisting of stars 
com.............cometic               R..............round 
cont............in contact            RR.............exactly round 
C...............compressed            Ri.............rich 
C.G.H...........Cape of Good Hope     s..............suddenly 
Cl..............cluster               s..............south 
d...............diameter              sp.............south preceding 
def.............defined               sf.............south following 
dif.............diffused              sc.............scattered 
diffic..........difficult             st.............stars 
dist............distance or           sev............several 
                distant               susp...........suspected 
D...............double                sh.............shaped 
e...............extremely,            stell..........stellar 
                excessively           S..............small 
ee..............most extremely        sm.............smaller 
er..............easily resolvable     triN...........trinuclear 
exc.............excentric             trap...........trapezium 
E...............extended              v..............very 
f...............following             vv.............very, very 
F...............faint                 var............variable 
g...............gradually             *..............a star: *10, a star of
gr..............group                                10th magnitude 
i...............irregular             **.............double star 
inv.............involved,involving    ***............triple star 
iF..............irregular figure      !..............remarkable 
l...............little,long           !!.............very remarkable 
L...............large                 !!!............a magnificent or otherwise
m...............much                                 interesting object
mm..............mixed magnitudes      st 9… .........stars from the 9th                 
mn..............milky nebulosity                     magnitude downwards
M...............middle, or in the     st 9…13 .......stars from the 9th     
                middle                               to 13th magnitude
                                                     


If you have never dealt with the NGC abbreviations before, perhaps a few examples will help.

NGC# Description Decoded descriptions
214 pF, pS, lE, gvlbM pretty faint, pretty small, little elongated, gradually very little brighter in the middle
708 vF,vS,R very faint, very small, round
891 B,vL,vmE bright, very large, very much elongated
7009 !,vB,S remarkable object, very bright, small
7089 !!,B,vL,mbM,rrr,13… extremely remarkable object, bright, very large, much brighter middle, resolved, stars 13th magnitude and dimmer
2099 !,B,vRi,mC remarkable object, bright, very rich, much compressed
6643 pB,pL,E50,2 st p pretty bright, pretty large, elongated in position angle 50 degrees,elongated in position angle 50 degrees, two stars preceding
© Copyright Rob Kantelberg