NGC 2359, Thor's Helmet (Winter 2018-19)

The brightest star inside the filamented blue box is HD 56925, a Wolf-Rayet star well on its way to blowing up as a supernova.  A Wolf-Rayet is a very large (10-80 solar masses) star that has become unstable in its advanced age. W-R stars burn very hot on their surfaces, as hot as 50,000 C. In this image, HD 56925 ionizes the local gas, here mostly hydrogen (reddish) and oxygen (bluish). The star has also blown out a bubble around itself, hence the box. There is much more to this nebula than a hot star in a box, though. At least some of the gas has been expelled from the star itself, while some of it is just interstellar gas that HD 56925's hot stellar wind has stirred up and energized.

This data is 9 hours of Ha and 7 hours of OIII with a 17" CDK and SBIG STXL 11002 through Astrodon filters, gathered by MPAstro in Australia.

Corona Australis Molecular Cloud, NGC 6726, 6727, 6729, IC 4812, Globular Cluster NGC 6723 (2018)

The Corona Australis Molecular Cloud produces new stars, hot and blue, that light up the dust like two eyes of a ghostly alien.  Each eye of this alien is two stars (not double stars, but aligned from our line of sight), yet each of the four is also a close double or multiple star.  Just below the left eye is fan-shaped nebula NGC 6729.  At the fan's point is R CoA and following up closely is T CoA, both very young stars. Just to the right is curly HH100, an Herbig-Haro object spewed from a newly forming star. Appearing above the nebulosity is NGC 6723, a background globular cluster some 30,000 light years away. This is from data obtained by Martin Pugh with a Tak FSQ106.