Two-panel mosaic -- North is up, East is to the left

Integration hours:
                                          North Pane          South Pane               Total
Ha:   300"/sub                       5.8                         4.3                        10.1
OIII:  300"/sub                       8.5                         9.1                        17.6
SII:  300"/sub                         7.5                         5.7                        13.2
RGB:   60"/sub                        3                             3                            6

Total Integration hours       24.8                      22.1                        45.9 

Acquisition Dates:  15 Nov - 6 Dec 2023 
Frames: All gain 100,  -5°C,  bin 1x1:
Bortle Dark-Sky Scale:  4

Nebular gases are displayed using a SHO color palette.  Broadband RGB stars were blended into the starless narrowband image.

Only a few Astrobin images of the supernova remnant G132.7+1.3 (HB3) show its full extent.  It is very large with an angular size of 90' x 120' requiring me to use a 2-pane mosaic to capture it all. 

It lies literally next to the Fish Head Nebula (lower left) and provides a good laboratory for scientists to study the interaction dynamics of the expanding remnant with its surrounding environment.  Its distance is generally thought to be the same as the Fish Head complex at around 2 kpc. 

The shells have expanded outward so much that some segments of the outer shell in the north and northwest periphery are barely visible optically except for the faint OIII signal.

A couple of well-documented, typical planetary nebulae also made it into the image and are identified in the crops below.  These tiny end-of-life corpses, typical of smaller stars (1 to 8 solar masses), vividly contrast with the aftermath of significantly higher energies released when a larger star, such as the one that created HB3 (estimated to be 30 solar masses), goes supernova.