A faint planetary nebula in constellation Hercules. Distance estimates are between 3300 (latest data) and 6800 light years (older data). A wonderful almost perfectly round bubble.

Its central white dwarf star is clearly visible und shines bright in blueish color, indicating an incredible surface temperature of equal or more than 110‘000 K. The star’s mass is now 0.6 solar masses, while the progenitor star had about 2.1 times the mass of the sun. It is located slightly offset from the bubble‘s center, which indicates asymmetric ejection of material from the progenitor star. The ejected shells themself are expanding with velocities from 32 to 37 km/sec. The event leading to the end of the progenitor star and the birth of this jewel in the sky took place about 23‘000 years ago.

More detailed information in this article:

https://iopscience.iop.org/article/10.1086/322489/fulltext

The bubble will expand further and slowly fading away over the coming some 10 thousands of years, the central star will become dimmer and dimmer on a much longer timescale until it disappears completely in the darkness of space.

Have a look also on the small distant galaxies in this image, especially the one which shines through the bubble in the lower right quadrant. The bright knot on the left edge might also be a galaxy in the far background.

Acquired over two nights, one night with substantial aurora glow in the background.

Celestron EDGE HD8 at Prime Focus F=2080mm, F/10

Skywatcher EQ6R Pro mount

ASI2600mc Pro

No filter

Bortle 4-5, Aurora polluted

147x180sec (7h21m)

PixInsight