(IAAC) NGC 40 - 8" F/10

Observer: Yann POTHIER (France)
Your skill: advanced (many years)
Object: NGC 40 (PK 120+09.1; PN G120.0+09.8; ARO 1)
Category: planetary nebula
Constellation: CEP
Object data: Vmag=12.3; Bmag=10.7; 60"x38"; type IIIb+III; central star of
Vmag=11.61 (HD 826); discovered by W. Herschel; ELCAT: [OIII, 496+501nm] =
0.3 x [Hbeta, 486nm].
RA/DE: 00h13.01m, +7231.3' (2000.0)
Date and UT of observation: 02 July 1992, about 23h30UT
Location & latitude: La Clapiere Obs. (France, latN44 40 00, longE06 27 36)
Site classification: rural, alt.1650m (5500ft)
Limiting magnitude (visual in UMi): 5.4
Transparency (1 to 5 - best to worst): 2
Seeing (1 to 5 - best to worst): 3
Moon up (phase?): no
Instrument: Meade SCT 8" (203mm), F/10
Magnification: 44-312x
Filters used: UHC, OIII
Description: at 44x, a mag11 central star is embedded in a diffuse nebula,
appears small and nebulous with UHC filter; with OIII, very circular; at
87x with UHC, good contrast, mag12 star at 1'W; at 145x with UHC,
homogeneous, nice, stands high power well; at 312x, hints of annularity;
central star of about mag10.5; about 60" in diameter.
Note: the sub-zero OIII/Hbeta ratio rarely found in PNs, typical of low
excitation PNs.
I can provide a scanned drawing of NGC 40 to anyone who can read the binhex
encoding of Eudora (for Mac); just mail me to try
(ypothier@abi.snv.jussieu.fr), it works quite often with other
Yann Pothier
11 impasse Canart, 75012 PARIS, FRANCE
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