This was one of the most challenging objects I have processed even with as much integration time I captured from 2018 and this year combined together. It was about on par with my processing of Ou4 back in 2017 and my processing skills are much better than then just a year into deep space astrophotography:
https://www.astrobin.com/315318/My first attempt at HFG1 was just okay. I was hoping for way better results. I think I have reached my limits with my skies and my aperture. Here was my first attempt back in 2018:
https://www.astrobin.com/371109/HFG1 was discovered in the Milky Way Emission Line Study in 1982 by Heckathorn, Fesen and Gull (A&A, 114, 414, 1982). It is defined as a type F planetary nebula by Tweedy and Kitter (Astrophys. J Supp Series 107, 255-262, 1996) meaning that is appears to be uniformly filled. Its mag. 14.5 central star is a close, precataclysmic binary, V664 Cas. One report suggests that V664 left a trail at least 20′ long of ~10,000 year old shocked material as it ejected matter and moved through the interstellar medium (ISM).
HFG1 has an interesting structure. It has a narrow rim approx. 14.5′ in diameter surrounding a 9′ diameter central region with an intervening gap. The rim is brightest in the south, suggesting that it interacted with the ISM. The rim is not complete and becomes too faint for our system to detect in the northeast. The core has three bright lobes toward the south and a central opening nearly devoid of emission. As shown in POSS II plates, blue (from OIII) shows more strongly that red (H-a), but still, both are described as faint. There appears to be a gradation from stronger OIII in the southern lobes of the core to stronger Ha toward the north.
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