on 1/19/03 10:00 AM, Marek Cichanski at marekc@No-Spam wrote:
> SIZE
>
> eS Excessively small
> vS Very small
> S Small
> cS Considerably small
> pS Pretty small
> pL Pretty large
> cL Considerably large
> L Large
> vL Very large
> eL Excessively large
John Herschel made an attempt to quantify these sizes, so they were not
totally subjective. I've copied his scale from his General Catalogue of
1864 (used by Dreyer in the NGC) which he qualified as "conveying a general
idea of the magnitudes intended by the convention words". The following
scale refers to coded descriptions of "nebulae" in the GC and NGC:
eS 3"-4"
vS 10"-12"
S or cS 20"-30"
pS or pL 50"-60"
cL or L 3'-4'
vL 8'-10'
eL 20' and upwards
As far as (open) clusters, Herschel considered 1' diameter as "eS" or "vS",
while 15'-20' qualified as "L" and 30'-40' as "vL". Of course, if an actual
diameter is mentioned in the NGC description that took precedence on the
intended size.
Steve G