OF NEBULAE AND CLUSTERS OF STAES. 
13 
Ex. 1. pB; vL; vg, vsmbMN15"; pmE162 0, 3; “pretty Bright; very Large; at first 
very gradually, then very suddenly much brighter in the middle to a nucleus 15" in dia- 
meter ; pretty much extended — the position of the longer dimension micrometrically 
measured 162°*3 (i. e. reckoned from the north round to 162°-3 in the direction nfsp).” 
The angles of position in all cases are to be understood as so reckoned. When deci- 
mals of degrees are annexed (or if integer, written decimally thus 151°0), they have been 
micrometrically measured. If thus, E 0° or E 45°, E 90°, they mean only in or near the 
meridian, or parallel or oblique to the meridian from nf to sp, &c., as the case may be. 
If with a + annexed, the position is from a more or less careful estimation. 
Ex. 2. R; psbM ill def O; pB*10 125°-4, 70"; “Round, pretty suddenly brighter 
in the middle to an ill-defined planetary disc; has a pretty Bright star of the 10th 
magnitude, whose position measured from the centre of the nebula is 125°-4, and 
whose distance also from the centre is 70" by estimation.” 
The relative situations of neighbouring stars or nebulae are invariably to be understood 
as thus reckoned, i. e. taking the centre of the nebula or other object described as a 
starting-point or origin of angle or distance. Thus S#s will mean that a small star is 
south of the nebula , #np nr that a star is near the nebula in a north preceding direction 
from it ; **4 s f, 3'n, that a double star follows the centre of the nebula 4 seconds of time, 
and is 3 f to the north of it. 
Ex. 3. Cl; pRi; pmC; L; st6, 10...15. “A cluster; pretty rich; pretty much 
compressed ; Large ; consisting of stars one of which is of the 6th, and the rest from the 
10th to the 15th magnitudes.” 
Attached or vicinary stars or small nebulae are always placed at the ends of the descrip- 
tions. Thus ©sf means that the nebula described “ has a globular cluster following 
and to the southward of it.” When, however, the description of a cluster ends abruptly 
thus, it is to be understood that “ the place taken is that of a conspicuous double 
star.” 
The 12 th column of the Catalogue contains the number of times that each nebula has 
been observed by both my Father and myself, whether its place were taken or not, com- 
prising all the cases in which the object has been seen, and whether described or not. 
Since attention has been drawn to the real or supposed variability of nebulae, and since 
it can hardly be doubted that comets have occasionally been observed as nebulae, this 
enumeration is not without its importance. In this column the abbreviation “ mon ” 
occasionally occurs. In such cases the nebulae have been so often and diligently observed 
for the purpose of exact delineation or “ monographing,” that a special enumeration of 
the observations would be impossible or useless. 
Finally, at the end of the line allotted to each nebula occur occasionally one or both 
of the marks * and f. The former refers to the notes appended to the Catalogue, the 
latter to the list of figured nebulae in which the publications wherein are contained 
figures of the nebulae are referred to by plate and figure — those at least which seem 
entitled, in the present state of astronomical instrument-making and pictorial representa- 
tion, to be pointed out to the observer as conveying any idea of their appearance. 
