The planetary nebula NGC 6905 ("Blue Flash Nebula") in the constellation of Delphinus on September 1/2, 2011. The gaseous remains of a red giant star are 4700 light years from Earth and were discovered by William Herschel in 1782.

Two 8 minute and one 9 minute exposures at ISO 1600 were added for this shot with the DeepSkyStacker software and the final image processing was done in Photoshop.
Equipment: Canon EOS 20Da camera, TeleVue coma corrector, Zambuto 16" f/5 quartz optics in a Dieter Martini dobsonian telescope, dual-axis Tom Osypowski equatorial platform, Lacerta MGEN autoguider, Teleskop-Service off axis system TS-OAG9 EOS.