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(IAAC) Cederblad 211 (R Aqr) / 22inch F/3.9



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, -1517' (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