(IAAC) NGC 2438 - 17.5" F/4.5

Observer: Yann POTHIER (France)
Your skill: advanced (many years)
Object: NGC 2438 (PK 231+04.2; PN G231.8+04.1; ARO 46; Sa 2-13)
Category: planetary nebula
Constellation: PUP
Object data: Vmag=10.8; Bmag=10.1; 68"x68" [internal=90", external=137" in
IDB]; type IV+II; central star of Vmag=17.5; discovered by Herschel in
1827; ELCAT: [OIII, 496+501nm] = 12 x [Hbeta, 486nm].
RA/DE: 07h41.83m, -1444.1' (2000.0)
Date and UT of observation: 03 January 1995, 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
Transparency (1 to 5 - best to worst): 1
Seeing (1 to 5 - best to worst): 3
Moon up (phase?): no
Instrument: Coulter 445mm/17.5" F/4.5
Magnification: 312x
Filters used: OIII, UHC
Description: at 312x, medium sized PN, of medium brightness, round with
quite sharp edges; estimated to be 70" in diam., obviously annular (ring
thickness of 25"); a 45 section of the ring centered on the NW is less
contrasty than the rest; a central star of mag14 is somewhat eccentric,
halfway between the geometric center and the inner WNW edge of the ring;
UHC provides a good contrast gain and OIII a very good one; a mag12 star is
10" from the SE border; this PN is located 6' to the N of M46's central
I can provide a scanned drawing of NGC 2438 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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