About image NGC 6905 also known as the Blue Flash Nebula, is a planetary nebula in the constellation Delphinus.
It is very small: its internal shell has angular dimensions 47"×34” and roughly conical extensions, with ansae-type formations along the major axis.
The central star is a white dwarf with an estimated surface temperature of 150.000 K. The distance of the nebula, as with most planetary nebulae, is not well determined and estimates range between 1.7 and 2.6 kpc.
(Text adapted from Wikipedia)
Being so small, this image is a strong crop of the original frame.
Technical data Optic GSO RC12 Truss - Aperture 304mm, focal lenght 2432mm, f/8 Mount 10Micron GM2000 HPSII Camera Moravian G3-16200 with external filter wheel 7 positions Filters Astrodon Gen2 E-Serie Tru-Balance 50mm unmounted LRGB Guiding system OAG Moravian M68 with guide camera Moravian G1-0301 Exposure details L 101x60" bin2 -20C R 40x60" bin2 -20C G 40x60" bin2 -20C B 40x60" bin2 -20C Total integration 3h41' Acquisition Voyager, PHD2 Processing Pixinsight 1.8, Photoshop CS5 SQM-L 21.00 Location Promiod (Aosta Valley, Italy), own remote observatory Date 29/30 August 2021