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(IAAC) Obj: R Aquarii nebula (Ced211, R Aqr, HD222800) - Inst: 17.5" f/4.5 dob



Observer: Steve Gottlieb
Your skills: Advanced (many years)
Date and UT of Observation: 2 Sep 1989
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: 100x, 140x, 220x
Filters used: None. UHC. OIII.
Object: R Aquarii nebula (Ced211, R Aqr, HD222800)
Category: Planetary nebula. Emission nebula.
Class: Spectral class Md (Symbiotic nova)
Constellation: Aqr
Data: Mag 5.8-12.4 var*; size 2'x1'
Position: 2343.8 -1517
Description:
[Editor's Note: This elusive "symbiotic star halo" can be found just
45 minutes SSE of Omega 2 Aqr, the E-ernmost star in the distinctive
little right triangle of stars at the very edge of the huge "flowing
waters" asterism of Aquarius. (Some will recognize Omega 2 as the E
"knee" of the Water Bearer.) From Omega 2 Aqr, use AAVSO's wonderful
finder chart http://charts.aavso.org/standard/AQR/R_AQR/RAQR-B.GIF ]
--
17.5": This is a very faint nebula surrounding R Aquarii (m 5.8-12.4),
a unique long-period variable (interacting binary consisting of a red
giant and a white dwarf). Surprisingly, at 100x and 140x no nebulosity
was visible; but the illuminating star, 10th magnitude R Aqr, showed
a mild contrast gain with both UHC and OIII blinking. A very similar
comparison star, mag10 GSC6404-0860 is 14' NW: this star loses 2+ mags
with filtration, while R appears of very similar brightness with the
filter, or possibly slightly brighter. At 220x, no nebulosity seen with
confidence, but once or twice I suspected a short extension to the NE.
--
[Reposted with the observers's permission from "Planetary_Nebulae".]
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