CED 211, R Aquarii

Aquarius

RA
23h 43m 49s

DEC
-15º 17' 04"

MAG ~7.5 (variable) for R Aquarii

Type: Symbiotic Star

CED 211 is one of the objects on my “save for steady seeing” list. Last week at the Oregon Star Party featured excellent seeing and I finally got a decent look at this intriguing object. I should note that the delay in getting this posted is because I returned from the OSP the evening of August 12 and discovered it was my turn to post the OOTW – sorry for the delay but the observing was awesome!

Here are my notes for CED 211 as it was nearing the meridian on the night of August 5th:

“Wow, this is really interesting! The star (R Aquarii) has a dirty, ruddy color to it at 155x but at 408x and 695x the color is washed out. The ‘star” of the show is the narrow streak of nebulosity that runs northeast to southwest, with a small knot on the northeast end. How cool is that!

The knot is best seen at 695x but is barely seen at 408x once I knew where to look. The northeast spike is brighter than the southwest counterpart, and the broadband filter (DGM’s galaxy filter) provides slightly more contrast. 2:21am, 21.76 SQM”

Wikipedia has this to say:
“R Aquarii is a symbiotic star believed to contain a white dwarf and a Mira-type variable in a binary system. The orbital period is approximately 44 years.[4] The main Mira-type star is a red giant, and varies in brightness by a factor of several hundred and with a period of slightly more than a year; this variability was discovered by Karl Ludwig Harding in 1810. It has a distance of about 200 parsec, and is one of the nearest symbiotic stars and a well known jet source.[5]
By its gravitational pull, the white dwarf draws in material from the red giant and occasionally ejects some of the surplus in weird loops to form the nebula seen in the linked image.[6] The whole system appears reddened because it is situated in a very dusty region of space, and its blue light is absorbed before reaching us.
The nebula around R Aquarii is also known as Cederblad 211. According to Tom Polakis,[7] as of 1998 no one had succeeded to observe this challenging object visually. It is possible that the nebula is the remnant of a nova-like outburst, which may have been observed by Japanese astronomers, in the year 930 AD.”

I’m sure CED 211 has been observed visually many times since 1998, but it’s interesting that a comment like that would be noted in Wikipedia. Has anyone seen the fainter filaments that are perpendicular to the brighter spikes I saw?

A DSS image looks like this:
CED 211 DSS.jpg

The HST image – it barely looks like the same object!
CED 211 HST.jpg

My sketch from last week:
CED 211 sketch crop.jpg CED 211 sketch crop invert.jpg

I also came across a wonderfully detailed amateur image of CED 211 here:
http://www.baskies.com.ar/PHOTOS/R_AQUIARII.htm

“Give it a go and let us know!”

Good luck and great viewing!