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(IAAC) Obj: He1-5 (PK60-7.1, PNG060.3-07.3, FG Sge, He2-457, He3-1844) - Inst: 17.5" f/4.5 dob
Observer: Steve Gottlieb
Your skills: Advanced (many years)
Date and UT of Observation: 15 Aug 2001
Location: Sierra foothills, CA USA (Elev 900m)
Site classification: Rural
Limiting magnitude: 6.4 to 6.8
Seeing: Fair to very good
Moon presence: None - moon not in sky
Instrument: 17.5" f/4.5 dob
Magnification: 220x
Filters used: None. UHC.
Object: He1-5 (PK60-7.1, PNG060.3-07.3, FG Sge, He2-457, He3-1844)
Category: Planetary nebula. Variable star.
Class: 3+2 (protoplanetary), Period 110? days
Constellation: Sagitta
Data: Mag 12 8.9vm*; size 35"
Position: 201155.9 +202006
Description:
[Editor's Note: The asterism of mag 12-13 stars Steve used to locate
this challenging but interesting object, lies close by a Right Angle
with mag 5-6 stars Eta & Theta Sagittae, just 45' SW of Theta. FG Sge
also lies just N of the midway point on a line between the Arrowhead
tip, Eta Sge, and the famous Blue Flash planetary nebula, NGC 6905.]
--
17.5" (8/15/01): Although FG Sge is currently below 15th magnitude,
there is a mag 12.5 companion ~10" E which was easily identified at
220x as the third of four in a NW to SE 6' chain of mag 12-13 stars.
An extremely faint halo ~20" diameter was strongly suspected with this
star embedded off-center. With a UHC filter, the nebulosity was more
evident though there was only a mild contrast gain. The central star
FG Sge is unique as an extremely rapidly evolving post-AGB star with
a late Helium flash on its way to the white dwarf stage.
--
[Reposted with the observers's permission from "Planetary_Nebulae".]
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