Great image Richard.
Unfortunately my rooftop terrace is to the southeast, so I can't do long
series on anything in Cygnus any more this year.
I might try next year, but I definately get less signal in Halpha than you
do, so it might be a tough target...

Stefan

"Richard Crisp" schrieb im Newsbeitrag
...
Just yesterday I became aware of a new "bubble nebula" in Cygnus near the
Crescent.

It is so perfectly round with such a well defined border that it really
looked like a plate defect in the discovery shot.

I imaged it last night at 0.41"/ pixel using the 18" f/12.6 classical
cassegrain (F=5760mm), the FLI Proline 9000 and the Baader Planetarium 50
x 50 mm square Halpha filter

The total exposure time was 10 x 20 minutes or 3 hours 20 minutes

http://www.narrowbandimaging.com/cbu...er_ha_page.htm

Perhaps I can get a chance to shoot some other emission line filters in
the near future.....

I looked at my old widefield from 2004 and reprocessed it a bit to better
highlight it. Unfortunately it is a coarse image scale but it is
definitely there