This PN was more of a challenge for me than most. I actually collected subs on three different rigs because I was never satisfied with what I had, the Ha and Oiii being so dim, and it having lots of interesting structure that needed exposing.
Subs for Ha and Oiii contributed from all three rigs.
Subs for LRBG come only from the Televue NP127is.
Imaged on the following nights:
Televue NP127is / ASI6200MM: 5/18/2021, 5/19/2021, 5/20/2021, 5/22/2021, 5/23/2021
Planewave CFK14 / ASI6200MM: 5/12/2021, 5/14/2021, 5/16/2021
Orion Optics AG12 / ASI178MM: 9/11/2020, 9/13/2020, 9/14/2020
Abell 74 (PK072-17.1) is a rarely imaged ancient planetary nebula, located in Vulpecula. Abell74 is a very large size planetary, measuring 13.8 arc minutes and has a magnitude listed at 12.2 to 15.8, depending on source. However, its surface brightness is very low, so there is no indication of its presence on the RGB image.
Contrary to other observers, my data shows the Ha and Oiii at comparable strength, but with the Ha concentrated in the outer ring areas, and the Oiii concentrated in the center. The central blue star, presumably the progenitor star, is very small, but clearly visible just below and to the left of the bright central white star. It has a close small white companion star. The white dwarf central star (WD 2114+239) has an effective temperature of 108,000 K. Distance measurements for planetary nebula have a wide variance. The distance provided for Abell 74 is ~ 2,500 light years.
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This Abell completes my collection of all 79 of the Abell planetary nebulae that actually are PNs. It also includes some of the other non-PNs. I will continue to add newer better versions for some of them taken with older gear and inferior processing.
Use the link below to see the entire collection.
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My Collections:
Abell Planetary Nebulae (Complete)Planetary NebulaeGalaxiesSharpless 2 Objects
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