Re: (IAAC) Obj: The Homunculus - Inst: 20" f5 Dobsonian
Andrew Murrell schrieb:
> Observer: Andrew Murrell
> Your skills: Advanced (many years)
> Date/time of observation:
> Location of site: Ilford NSW Australia (Lat , Elev )
> Site classification: Rural
> Sky darkness: 6.5 <1-10 Scale (10 best)>
> Seeing: 8-9.5 <1-10 Seeing Scale (10 best)>
> Moon presence: None - moon not in sky
> Instrument: 20" f5 Dobsonian
> Magnification: 160-700
> Filter(s): none
> Object(s): The Homunculus
> Category: Planetary nebula. Emission nebula.
> Class: stellar ejecta
> Constellation: carina
> Data: mag 6.5 size 30"
> Position: RA 10:45.1 DEC -59:41
> The Homunculus is the small nebulae that surrounds Eta Carina. It is the
> of stellar material that was ejected from the star about a century ago. This
> is the
> only nebulae that shows an obvious colour, Bright orange. This colour is very
> striking against the star background. The initial observation was at 160x.
> This shows
> the surrounding keyhole nebulae NGC3372, which defies description. The
> appears as a peanut shaped orange blob about 30" across. At 300x it appears
> as a bright
> hazy star with a lobe or bubble of material on either side, orietated SW-NE.
> The lobe
> to the SW is the brightest, and appears granular with a dark lane running
> middle which curls to the southat the end. The NE lobe is fainter and shows
> no internal detail
> The center star is about 6.5 magnitude and has a jet progecting to the north
> about 5" long.
> Averted vision at this power intensifies the colour and shows a bright knot
> 5" WSW of the star
> in the SW lobe. By increasing the magnifaction to 720x even more detail was
> glimpsed. In moments
> of perfect seeing the granulation in the NE lobe became apparent. The bright
> knot became visible
> with direct vision,and the colour remained. The dark lane seen before in the
> SW lobe lost some of
> its structure, looking more difuse and ending in a small dark hole positioned
> about 5" from the southern
> edge of the nebulae. The higher magnifaction increased the contrast. The edge
> of the nebulae remained
> sharp across the entire perimeter and the arm or jet was easily picked up.
> What became most noticable
> about the homunculus was the FAINT halo that surrounded the entire object and
> doubled its size.
> The difuse glow had an indistinct edge and appeared evenly distributed about
> the object. No intermal
> details were seen in this faint envelope
> A right angle of 15th magnitude stars are positioned about 15" NW of the
> central star adding to the
> view at this power. As a side note to this observation stars of 4th magnitude
> and brighter had difraction
> rings visible, one complete ring and two partial. The seeing was the best in
> several years that I had seen
> Reducing the magnifaction to 300x I looked for the faint halo but it would
> not reveal itself, probably due
> to the glare from the star and the nebulae.
> This goes down as one of the TOP 5 objects in the entire sky.
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Very nice observation report. I will never see such objects with my 20incher here
With kind regards from Germany, Jens
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