Hydrogene alpha emission nebulae around g Cygni
The constellation Cygnus sports a lot of beautiful HII emission nebulae. Some of them are grouped around g Cygni. So I just used g Cygni as the guide star (there should be such bright guide stars near all the celestial deep sky objects!) for the exposure. But I found less HII emission nebulae on the negative than I thought. Again the focal length of the C9 was too big. In the top left corner is the open star cluster NGC6910 with a visual brightness of 6.7 mag.
Date: 05 September 1999, 00.50h CET
Lens: f=1480 mm f/6.3
Guiding: manually with C5 at 278x
Exposure time: 30 minutes
Film: Kodak Royal Gold 400
During the exposure dew precipitated on the correction plate. As a result the star images are a little bit diffuse.