Say what? A Christmas ornament in space?
NGC-6905, also known as the Blue Flash Nebula, is a planetary nebula in the constellation Delphinus(The Dolphin). It was discovered by William Herschel in 1784.
The central star is 14.0 mag. The distance of the nebula, as with most planetary nebulae, is not well determined and current estimates place it at 7,500 light years away.
The shape of NGC-6905 is characterized by an internal shell with angular dimensions 47″ × 34″ and roughly conical extensions, with ansae-type formations along the major axis,
It looks tiny in the telescope, tip to tip NGC-6905 is about 1.2 arc minutes across, so crank up the magnification a bit to see more detail.
The central star, a white dwarf is estimated to have surface temperature 150,000 K. This wonderful looking dying star is blowing off its outer atmosphere, which will be the fate of our Sun as well.
NGC-6905 can be detected under dark skies with a 4-inch telescope as it shines at magnitude 10.9, but the Blue Flash is better observed with larger telescopes(like my homemade 16 inch diameter scope) you can make out some of the structure in the outer shell. It’s Conical Shape definitely reminds me of the old Christmas ornaments, and this Planetary Nebula is absolutely beautiful in this rich Milky Way star field.
I included a cropped close-up view as well to help you see some structure in this Cool “Blue Flash” planetary nebula.
C8 SCT telescope @ F6.3, QHY183C Cooled Cmos RGB Camera, Bisque MYT Mount, and 54 minute exposure total on 11-17-2020 from my backyard Observatory in Dayton, Ohio.
Piggy backed a C90 (1300mmFL)Guide scope with QHY5IIL Cmos camera for guiding via PHD2.
Best Regards,
John Chumack