Just west of the Fishhead Nebula (IC1795) and the Heart Nebula, there is a large supernova remnant: SNR G132.6+01.5, more commonly referred to by its radio designation of HB3. That catalog, by R. Hanbury Brown and C. Hazard, was one of the earliest radio surveys, published in 1953 using the Jodrell Bank antenna in the UK. A small fragment of H-alpha emission was catalogued as LBN641, but the OIII optical emission wasn’t noted until 1982 by Fesen and Gull, though the film was barely able to reveal any details. This supernova is estimated to have exploded about 30-50 thousand years ago.
The OIII here is very faint, and interestingly the SII is brighter than the H-alpha. I captured several hours of SII, but I’ve discarded it in this image, as the HOO palette better reveals HB3. I find the structure to be remarkably similar to SNR G65.3+5.7, where there also appears to be two concentric shells.
- Exposures (-10ºC):
- H-alpha: 75×180s
- OIII: 208×180s
- Total exposure time: 14.15 hours
- Taken from Doylestown, PA, Dec 13-15, 2023
- Telescope: Takahashi FSQ106ED w/ 0.73x reducer (f/3.7)
- Camera: ZWO ASI2600MM-Pro with Astrodon filters
- Mount: iOptron CEM60
- Guiding: ZWO ASI174MM (off-axis)
- Acquisition: NINA + PHD2 and ASTAP
- Processing: AstroPixelProcessor, PixInsight
Deep-sky Imaging 