(IAAC) H 3-75 (PK 193-09.1; PN G193.6-09.5) - 17.5" F/4.5

Observer: Yann POTHIER (France)
Your skill: advanced (many years)
Date and UT of observation: 29 December 1997, about 22h30 UT
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 ti=
Transparency (1 to 5 - best to worst): 1
Seeing (1 to 5 - best to worst): 3 (stellar stars until 160x)
Moon up (phase?): no
Instrument: Coulter 17.5" (445mm) F/4.5
Magnification: 211x
=46ilters used: OIII, UHC, Hbeta
Object: H 3-75 (PK 193-09.1; PN G193.6-09.5; PK 193-9 1; ARO 218)
Category: planetary nebula
Constellation: ORI
Object data: Vmag=3D13.9; dim.24"x24" (35"x35" according to IDB); type ?;
central star of Vmag=3D?; discovered by Mayall in 1964.
RA/DE: 05h40.7m, +12=B020' (2000); Uranometria 181
Description: at 211x and OII, small to medium sized PN, faint, round with
quite sharp edges; estimated diameter about 24"; easily found: to be
searched at 100x and above with UHC or OIII (seen at 74x without filter
when already located); homogeneous with OIII, brighter towards the center
without filter (because of central star which appears around mag15); UHC
has a slight contrast gain, OIII a very good one and Hbeta has no positive
I can provide a scanned drawing of H 3-75 to anyone who can read the binhex
encoding of Eudora (for Mac); just mail me to try
(ypothier@abi.snv.jussieu.fr), it works sometimes with other
Yann Pothier
11 impasse Canart, 75012 PARIS, FRANCE
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