(IAAC) Obj: NGC6309 (Box Nebula) - Inst: 4.5" Homemade Dobson reflector, f/8

Lewis J. Gramer lgramer at upstream.net
Mon Aug 23 18:00:33 EDT 2004


This was an interesting obs, also, Ante - it shows that
though UHCs do increase *contrast* between a PN and its
surrounding objects, they also reduce *total light*. :)

BTW, this object is a fine sight in larger telescopes:
with 15" or more aperture under decent suburban skies,
it looks to me VERY much like an exclamation mark "!",
along with its nearby "dot", mag 9 star GSC05653:197.
  http://www.visualdeepsky.org/logs/msg03591.html

Also, note that it has been logged with a little detail
on IAAC, by an observer using another 4" instrument at
a more southerly site (and nearer to culmination time):
  http://www.visualdeepsky.org/logs/msg02599.html

So it may be worth another look next Spring!

Clear skies,
Lew


> -----Original Message-----
> From: netastrocatalog-announce-bounces at visualdeepsky.org
> [mailto:netastrocatalog-announce-bounces at visualdeepsky.org]
> On Behalf Of Ante Perkovic
> Sent: Monday, August 23, 2004 10:46 AM
> To: IAAC
> Subject: (IAAC) Obj: NGC6309 (Box Nebula) - Inst: 4.5"
> Homemade Dobson reflector, f/8
>
>
>   Observer: Ante Perkovic
> Your skills: Intermediate (some years)
> Date/time of observation: August 11th 2003, 23.30h
> Location of site: Tugare, near Split, Croatia (Lat 43.4 N, Elev 250m)
> Site classification: Rural
> Sky darkness: 5.0 <Limiting magnitude>
> Seeing:
> Moon presence: None - moon not in sky
> Instrument: 4.5" Homemade Dobson reflector, f/8 ("babydob")
> Magnification: 25x, 48x, 79x
> Filter(s): None, UHC
> Object(s): NGC6309 (Box Nebula)
> Category: Planetary nebula
> Class:
> Constellation: Oph
> Data: mag 11.6  size 20"x10"
> Position:
> Description:
>   25x: Invisible with both direct and averted vision. With UHC, I
> couldn't see a thing in the entire FOV.
>   48x: Small, very faint, undoubtedly fuzzy object popped up for a
> moment and went back to darkness.
>   79x: Visible 1/3 of the time. Averted vision helps a little. This
> planetary is very faint, small, but undoubtedly fuzzy. UHC
> just showed
> total darkness.
>
> The nebula was 22 deg above the horizon.





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