The first object called planetary nebula was named more than two centuries ago (NGC 6720; Ch. Messier, A. Darquier, 1779). Due to the work of W. Herschel altogether 13 PNe were known at the end of the 18th century. In addition, further 65 PNe were found in the 19th century.
A substantial increase of new PNe can be registered since 1945 as a result of spectral surveys and of Schmidt cameras. (About 90% of known PNe have been discovered since 1945.) In the last decade the slight increase of new PNe is mostly due to observations in no-visual regions (mainly in infrared) and due to the use of CCD cameras, which are
more sensitive than photographic plates. The following catalogues or lists (partly mentioned already in CGPN(1967)) are given below.
The distribution of the number of PNe discoveries is given in the following figure:
Fig.5 Dicoveries of PNe until 2000 in the respective decade.
|Catalogue or list||Number of||Number of|
|Vorontsov-Velyaminov, Parenago (1931)||121|
|Perek, Kohoutek (1967) - CGPN(1967)||1036|
|Kohoutek (1978-2000) - Supplements 1-6 to CGPN(1967)||721||247|
|Acker et al. (1992) - SECGPN||1143||*)||330|
|Acker et al. (1996) - Supplement 1 to SECGPN||242||*)|
|This catalogue - CGPN(2000)||1510||245|