Seiji N
HFG1 and Abell 6 revised again
Note from 2015 (modified for the new processing using Pixinsight)
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HFG1 (Heckathorn-Fesen-Gullis 1) is a very faint and large (huge), ancient planetary nebula in Cassiopeia, with almost no Sii, small Ha, and a moderate amount of Oiii emissions. The more stereotypical, "bubble"-shaped Abell 6 has both Ha and Oiii. Note a bow shock surrounding HFG1 and a faint Ha tail. As other postings at AB and other sites commented, this has turned out to be one of the most difficult imaging I have done so far with C8 Hyperstar 3 (stopped down to F/3) +Atik460ex+5nm Astrodon filters. Shot over 3 nights in an unusually hazy October sky from Grandview Campground, Inyo, CA. Ha, Oiii, and Sii were used to generate both HST and synthetic natural color palette images, which were blended and used.
HFG1 and Abell 6 revised again
Note from 2015 (modified for the new processing using Pixinsight)
------------------------------------------------------------------------------
HFG1 (Heckathorn-Fesen-Gullis 1) is a very faint and large (huge), ancient planetary nebula in Cassiopeia, with almost no Sii, small Ha, and a moderate amount of Oiii emissions. The more stereotypical, "bubble"-shaped Abell 6 has both Ha and Oiii. Note a bow shock surrounding HFG1 and a faint Ha tail. As other postings at AB and other sites commented, this has turned out to be one of the most difficult imaging I have done so far with C8 Hyperstar 3 (stopped down to F/3) +Atik460ex+5nm Astrodon filters. Shot over 3 nights in an unusually hazy October sky from Grandview Campground, Inyo, CA. Ha, Oiii, and Sii were used to generate both HST and synthetic natural color palette images, which were blended and used.