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Re: (IAAC) Obj: M1-79 (PK93-2.1, png93.3-2.4) - Inst: 20" f/5 dob



>little nebula presented an underwhelming image. However, as seeing briefly
>settled and I cranked power to 360x, I could finally unequivocally discern
>the elongated nature of this PN. It had a somewhat irregular, "fat peanut"
>shape in direct vision, with near perfect N-S orientation. The N "lobe" was
>somewhat brighter. Screwing in a UHC and then an OIII had little effect for
>me tonight: the OIII did enhance the irregularity of the nebula, but failed
>to appreciably increase its 20"x10" size. Reviewing this log later, against
>Yann's and Jeff Bondono's descriptions, as well as the DSS image on the Web,
>I had to conclude that what I actually observed tonight was the inner core
>of this nebula, while these observers (under better conditions) had logged
>the outer ring of this very unusually-shaped (proto?)planetary. Perhaps some
>Summer night, under cirrus-free conditions, I can log this outer ring also!
>--
Hi lew and all,
As you mention, maybe the conditions are to blame but also the less than
perfect optics of my 17.5" Coulter mirror (some spherical aberration) added
to the fact that at the time of my log-observation the scope was not very
well collimated, -I only became aware of the collimation importance in
1998. So this combination of low optical quality/some misalignment must
have "troubled" my deep sky observation, specially for tiny features even
in brighter objects. What about your 20-inch telescope ?
clear skies, yann.
PS: I have become quite lazy with my logs but have been kept away by the
edition of next Ciel Extreme's issue. BTW, anyone with Barnard 142-143
observations ?
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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