(IAAC) M 76 (NGC 650, NGC 651) - 17.5" F/4.5
Observer: Yann POTHIER (France)
Your skill: advanced (many years)
Object: M 76 (NGC 650, NGC 651; PK 130-10.1; PN G130.9-10.5; ARO 2)
Category: Planetary nebula.
Object data: Vmag=10.1; Bmag=12.2; 87"x42" [193x118" in IDB]; type III+VI;
central star of Vmag=15.6; discovered by Méchain in 1780; ELCAT: [OIII,
496+501nm] = 16 x [Hbeta, 486nm].
RA/DE: 01h42.30m, +51°34.7' (2000.0)
Date and UT of observation: 23 August 2001, 01h15 UT
Location & latitude: La Clapiere Obs. (France, latN44 40 00, longE06 27 36)
Site classification: rural, alt.1650m (5500ft)
Limiting magnitude (visual in UMi): 6.3
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
Filters used: OIII
Description: at 400x & OIII, medium to large PN, bright, rectangular and
bilobed; its edges are sharp on the main area (84"x43" in a NE-SW axis) and
diffuse on the faint extensions; SW lobe of the main part is the brightest
with an extremely compact knot on its NW side; a slightly darker channel is
dividing the two lobes (SW & NE) and is about 25" large; a faint "arm"
leaves the E side of the SW lobe towards E and then to the N (50"x43") with
a diam.23" globule against the darker channel; the other faint extension
(arm) leaves the W side of the NE lobe towards W and then S, with a large
globule of diam.29" detached from the main area of the PN 20" from it and a
second one diam.20" aside from the SW lobe a lot fainter; a mag.15 star is
against the far S side of the main "hourglass" a few arcseconds from it; no
central star seen in these conditions, no color noted; UHC gives a good
contrast gain, Hß a very good one and Hbeta none.
I can provide a scanned drawing of M76 in .jpg to anyone who can read the
binhex encoding of Eudora (for Mac); just mail me to try
(firstname.lastname@example.org), it works quite often with other configurations...
Carpe noctem, Yann.
11 impasse Canart, 75012 PARIS, FRANCE
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