Object: NGC 2438 (PK 231+04.2; PN G231.8+04.1; ARO 46; Sa 2-13) 
Observer: Yann POTHIER (France)  
Your skill: advanced (many years)     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, -14°44.1' (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  
area.