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Ced 211 (17,994 of 18,816)

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Ced 211

Ced 211

RA: 23h 43m 48s
Dec: −15° 17′ 0″

Con: Aquarius
Ch: MSA:1351, U2:304, SA:17

Ref: VizieR VII/231

(reference key)

Type: bright nebula

Mag: B=?, V=?

Size: 1.5′ x 1.5′
PA: ?

Published comments

Cederblad, S. (1946) [VII/231]

Ced 211 (-16 6352)

Position (1900): RA 23 38.6, Dec - 15 50

Star: -16 6352 (variable Mp and V, SpT=M7e)

Spectrum of nebula: emission spectrum (observed)

Classification: Neb associated with mainly one star (which may be multiple) - star surrounded by a neb envelope with conspicuous structure (eg. IC 5146)

Size: 1.5'x1.5'

Notes: "-16 6352 = HD 222800 = Boss 32948 = R Aquarii nebulous. Disc. Lampland 1921 (456). (457, 486)."

Modern observations

Yann POTHIER (IAAC)

Observer: Yann POTHIER (France)

Your skill: advanced (many years)

Date and UT of observation: 19 August 1998, about 02h15 UT

Location & latitude: La Clapiere Obs. (France, latN44 40 00, longE06 27 36)

Site classification: rural, alt.1650m (5500ft)

Limiting magnitude (visual): 6,31

Seeing (1 to 5 - best to worst): 1

Moon up (phase?): no

Instrument: DobNewt 22" F/3.9

Magnification: 315x

Filters used: OIII

Object: Cederblad 211 (R Aqr)

Category: diffuse nebula

Constellation: AQR

Object data: 2'x1'; R Aqr Mira type var. v5.8-12.4 in 13 months

RA/DE: 23h43.8m, -15°17' (2000); Uranometria 260/304; (Sky Atlas 17)

Description: My attention has been drawn to this object by a John ISLES article in S&T (Oct.94) who asked for visual sightings. It is a small nebula extremely faint with rather sharp edges, visible only at high power with OIII filter (Hbeta was of no use); R aqr itself is bright (about mag.10) and orange-red; two faint nebular streaks extends from it: one of 10"x7" (cometary shape) is going to the WSW and the other of 8"x6" (curved) to the ENE; the second extension is brighter and is curving towards a stellar knot of about mag.16. I checked R Aqr with a visual spectrographic tool and the spectrum looked typical of Me stars that is with some emission lines and some areas darkened by dust (a beautiful one). I believe the superior seeing of this night to be the crucial factor in seeing this nebula as we have also seen it with my 17.5" Coulter (optics suffering from spherical aberration) that same night, but I have tried it unsuccessfully some nights later with the same 17.5" but deteriorated seeing. Maybe the nebula is more easily visible when R Aqr is near minimum...

I can provide a scanned drawing of Ced 211 to anyone who can read the binhex encoding of Eudora (for Mac); just mail me to try (ypothier@abi.snv.jussieu.fr), it works sometimes with other configurations...

Yann Pothier tel: 01 43 41 43 29

11 impasse Canart, 75012 PARIS, FRANCE

Email: ypothier@abi.snv.jussieu.fr

Site : http://pegase.unice.fr/~skylink/publi/cielextreme

[amastro] Ced 211?

Hi all,

Has anyone seen Cederblad 211, an emission nebulosity surrounding R AQR? I tried last night using my 17-in without success. BTW, the POSS image shows a bizarre looking cross surrounding R, it looks

bright enough that it might possibly be visible. -Jay-

------------------------------------------------------------------------

]I didn't make a definite sighting of nebulosity, but I did record a filter

]response to R Aqr in my 17.5" a couple of years back. I'm curious if

]anyone else can confirm this.

Thanks Steve,

I tried again last night to see Ced 211 with a variety of powers, 74-221x with no success. Very occasionally I suspected something nebulous immediately N of the star, but I think that was averted imagination!

I blinked with O III, UHC, Daystar and DS. No filters resulted in any contrast gain for R AQR. Perhaps this boost depends on where R is on its light curve? It is a nice saturated copper colored star at present. -Jay-

------------------------------------------------------------------------

Jeff and Steve;

I have another negative sighting of Cederblad 211 around R Aqr, I did not see the star as nebulous in the 13 inch at 150X on a night I rated 7/10 for seeing and transparency.

Anybody with a BIG scope try it???

Steve Coe

------------------------------------------------------------------------

I didn't make a definite sighting of nebulosity, but I did record a filter response to R Aqr in my 17.5" a couple of years back. I'm curious if anyone else can confirm this.

17.5": Surprisingly, at 100x and 140x no nebulosity was visible but the illuminating star 10th magnitude R Aquarii showed a mild contrast gain with UHC and OIII blinking. A very similar comparison star is 14' NW - this star loses 2+ magnitudes with filtration but R appears very similar brightness with the filter or possibly slightly brighter. At 220x, no nebulosity was seen with confidence but once or twice I suspected a short extension to the NE.

Steve Gottlieb

NGC/IC Project Adventures in Deep Space

http://www.ngcic.org/ http://www.angelfire.com/id/jsredshift/

[amastro] A Close Look at R Aquarii

[amastro] A Close Look at R Aquarii

Hi, All

Observations of the peculiar variable star R Aquarii using high magnification have revealed a curious nebula surrounding the star.

A 24" f/4.5 reflector was used Friday evening to see a remarkable nebulous "ring" around the star. Nothing unusual was noted at 228X and increasing the power to ~340X a small nebulous haze (major axis running E-W) was seen. During moments of steady seeing at 458X , the haze sharpened into a detailed annular structure. Although dim, this nebulosity was not particularly difficult to see. I didn't try to estimate the size of the nebula but it requires a fair amount of power to be seen.

I rating the seeing as "good" (Antoniadi II), transparency fair and a naked eye limit at ~6 Friday evening.

A second observation using the Atlanta Astronomy Club's 20" f/4.5 reflector Saturday evening involved the use of filters. An "UltraBlock" filter improved the visibility of the R Aquarii nebula but the "ring" remained invisible. I suspect that the larger aperture used Friday evening made the difference. With my OIII filter , the eastern lobe of the nebula appeared a bit brighter than the western lobe.

Dave Riddle

------------------------------------------------------------------------

] Is this a first-ever visual observation?

]\Brian

I'm not sure it was the 'first' (I believe Steve Gottlieb has tried this object before), but it was hardly a 'singular observation'[grin]

Quite a number of others from the AAC saw the object with the 24-inch including list members Alex Langoussis (sp) and Art Russell and myself), and it was "easy" enough for observers with only modest skills to see "something".

I am working on a composite sketch from observations with the 24 and 20-inch scopes, hopefully I can post it on here later this evening if no one objects.

- Rich

------------------------------------------------------------------------

For those interested in my Cat's Eye and Ced 211 drawings, here are a couple

sites to check out (with a little help from Alex Langoussis):

http://www.mindspring.com/~aleko/N6543.jpg

http://www.mindspring.com/~aleko/ced211.jpg

- Rich

------------------------------------------------------------------------

Contemporary observations

Auke Slotegraaf

1997 October 28

1997 October 28, Tue/Wed: Jonkershoek, seeing 3, transparency 3, sky darkness 4, lim.mag. at south pole 6.0 (naked eye), 10.7 (binoculars). 11x80 tripod-mounted. "Not seen."

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