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(IAAC) IC 418 - 4.25" F/7.8
Observer: Yann POTHIER (France)
Your skill: advanced (many years)
Object: IC 418 (PK 215-24.1; PN G215.2-24.2; ARO 3)
Category: planetary nebula
Constellation: LEP
Object data: Vmag=9.32; Bmag=10.7; 14"x11"; type IV; central star of
Vmag=10.17; discovered by Fleming in 1891; ELCAT: [OIII, 496+501nm] = 1 x
[Hbeta, 486nm] !!!.
RA/DE: 05h27.5m, -12°42' (2000)
Date and UT of observation: 03 Janvier 1991, late evening but before moon rise
Location & latitude: La Clapiere Obs. (France, latN44 40 00, longE06 27 36)
Site classification: rural, alt.1650m (5500ft)
Limiting magnitude (visual in UMi): 6.0 with averted vision
Transparency (1 to 5 - best to worst): 1
Seeing (1 to 5 - best to worst): ?
Moon up (phase?): no (18th day)
Instrument: Japanese 4.25" F/7.8
Magnification: 36-180x
Filters used: no, visual spectroscope
Description: located easily with prism at 36x like a thin continuous
spectrum (central star) crossing a stellar knot (nebula), quite bright;
without prism, small PN, nebulous with central star quite distinct
surrounded by a tiny nebulous atmosphere; at 72x, larger with easier
central star, bluish (?) and the sepctroscope reveal two OIII images
[corrected afterwards: it must be the Hbeta and OIII -at 501nm- images that
separates; see observation with 22-inch scope for more detail on the
spectroscopic peculiarities of this object]; the image is the same until
180x, a nice central star surrounded by a regular but small nebulous
enveloppe.
Yann Pothier
11 impasse Canart, 75012 PARIS, FRANCE
ypothier@abi.snv.jussieu.fr
ypothier@closun.snv.jussieu.fr
http://www.astrosurf.org/cielextreme
http://www.astrosurf.com/cielextreme
http://astrosurf.org/skylink/publi/cielextreme,
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