2 
SIR J. E. W. HERSCHEL’S CATALOGUE 
tory of Copenhagen. Again, from the Observatory of the Collegio Romano, under the 
direction of Signor Secchi, have emanated many valuable observations, and from that at 
Harvard College, Cambridge, U.S., under the late and present Professors Bond, some of 
the most striking pictorial representations of particular nebulae which we possess. 
Neither ought a short but very valuable memoir by the late E. Mason, printed in the 
7th volume of the Memoirs of the American Academy of Arts and Sciences, to be passed 
in silence ; containing as it does a very elaborate and minute examination, and some 
excellent delineations of several highly interesting nebulae, particularly those in the 
great nebulous region of Cygnus. To M. Auwers also we owe many accurate and 
valuable observations, besides a Catalogue comprising the whole series of Sir William 
Herschel’s nebulae arranged in order of right ascension and reduced to a common epoch, 
of which more hereafter. Should the efforts which are now making to procure for the 
University of Melbourne in Australia a reflector of the first magnitude prove, as is to be 
hoped, successful, it is understood that one of the principal uses to which it will be 
devoted will be the examination and exact delineation of the numerous and wonderful 
objects of this class which the southern hemisphere presents. 
These circumstances, but more especially the last-mentioned, render it extremely 
desirable to have presented in one work, without the necessity of turning over many 
volumes, a general catalogue of all the nebulae and clusters of stars actually known, both 
northern and southern, arranged in order of right ascension and reduced to a common 
and sufficiently advanced epoch which may serve as a general index to them, and enable 
an observer at once to turn his instrument on any one of them, as well as to put it in 
his power immediately to ascertain whether any object of this nature which he may 
encounter in his observations is new, or should be set down as one previously observed. 
For want of such a general catalogue, in fact, a great many nebulae have been, from 
time to time, in the ‘Astronomische Nachrichten’ and elsewhere, introduced to the world 
as new discoveries, which have since been identified with nebulae already described and 
well known. Many a supposed comet, too, would have been recognized at once as a 
nebula, had such a general catalogue been at hand, and much valuable time been thus 
saved to their observers in looking out for them again. 
Besides these there are other considerations which have weighed with me in under- 
taking the task of compiling such a general catalogue. Having, in the course of my 
own observations, received the greatest possible assistance from the possession of a Manu- 
script Catalogue of all the nebulae and clusters discovered by my Father, brought to the 
common epoch 1800 - 0, and arranged in zones of 1° in breadth in polar distance, by his 
sister the late Miss Carolina L. Herschel, it seemed to me nothing less than a debt of 
gratitude, not merely to acknowledge that assistance, but to avail myself still further of 
it to complete the list of his nebulae by supplying from that catalogue the places of all 
those nebulae among them which had escaped my own observation (a very numerous 
list), and by inserting from it all those places of nebulae observed by myself which were 
deficient in either element (of R.A. or P.D.), or in which I had reason to apprehend 
