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R
Aquarii is
a symbiotic double star consisting of a Mira-type red giant transferring gas to presumably a
White Dwarf (more
here).
From time to time, the system ejects some of this material. This material forms spiraling filaments
that are known as Ced 211.
I
had observed R Aqr already some weeks before with a 16 inch Dob under less than optimal
seeing conditions, where I could spot the elongated form of the nebula but
no further detail. This night, the seeing was better than average. With my
22" Dob at 500x without filter only the conspicuously red giant star was
visibly, no nebulosity. With the OIII filter, the brightness was reduced
only slightly and a bright small condensation became visible around the
now very much suppressed star. On one side of the Nebula, approximately
NE, an extension curving toward N could be easily seen, which had another
brighter condensation at its tip. At the other side, the nebula was
broader and did not extend that far. With UHC filter (Astronomik, with
transmission window in the red spectral range), the star became more
prominent and with H beta (Lumicon) only the star could be seen. To the
left is a rough sketch of what could be seen at the eyepiece using OIII
filtering.
Sometimes
I suspected more material further out toward South, but I was not
completely sure about this.
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