(IAAC) NGC 2392 - 17.5" F/4.5

Observer: Yann POTHIER (France)
Your skill: advanced (many years)
Object: NGC 2392 (PK 197+17.1; PN G197.8+17.3; ARO 24; clown nebula)
Category: planetary nebula
Constellation: GEM
Object data: Vmag=9.1; Bmag=9.9; 47x43"; type IIIb+III; central star HD
59088 of Vmag=10.5 (Bmag=9.1); discovered by Herschel in 1786 (as a PN by
Lassell in 1853); ELCAT: [OIII, 496+501nm] = 16 x [Hbeta, 486nm].
RA/DE: 07h29.16m, +2054.8' (2000.0)
Date and UT of observation: 26 December 1994, 23h30UT
Location & latitude: La Clapiere Obs. (France, latN44 40 00, longE06 27 36)
Site classification: rural, alt.1650m (5500ft)
Limiting magnitude (visual in UMi): 6.31 with indirect vision 25% of the time
Transparency (1 to 5 - best to worst): 1
Seeing (1 to 5 - best to worst): 4
Moon up (phase?): no
Instrument: Coulter 445mm/17.5" F/4.5
Magnification: 45-312x
Filters used: OIII, UHC
Description: at 312x, medium sized PN (large with filter), bright and
round; about 47" in diam. without filter and 64" with OIII (estimated on
drawing) because of a weaker external corona seen at 312x and OIII; a
brighter central area is seen, a little oval, about 30"x25" N-S; UHC
provides a good contrast gain and erases the central star, OIII gives a
very good contrast gain and the extended edges are getting sharper; the
nebula looks bluish at 45x; the mag8.5 star is at 1.6'N from the central
I can provide a scanned drawing of NGC 2392 to anyone who can read the
binhex encoding of Eudora (for Mac); just mail me to try
(yann.pothier@fnac.net), it works quite often with other configurations...
Yann Pothier
11 impasse Canart, 75012 PARIS, FRANCE
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