Heckathorn-Fesen-Gull 1 nebula of extraordinary beauty is visible in the constellation Giraffe. It was discovered in 1982 by the Heckathorn-Fesen-Gull trio while studying the Milky Way's emission lines.
Marcel Drechsler wrote a great description of this nebula on his website (
www.sternwarte-baerenstein.de): "HFG1 was created by the central star V664 Cas. This is not a single star, but a dense binary star system consisting of a white dwarf and a sun-like star, which are only a few million kilometres apart and orbit every 14 hours.
Because the binary system V664 Cas moves very fast at 29 to 59 kilometres per second and ploughs through the interstellar medium together with the nebula, a bluish arc shock occurs. HFG1 leaves behind a long, red trace of approx. 10,000 year old gas.
The image of HFG1 clearly shows the interesting structure of the planar nebula. HFG1 is defined as a type F planetary nebula, which means that it appears to be evenly filled. The narrow, bluish arch shock surrounds a central region with a gap in between. The arch shock is brightest in the south, indicating that it interacts most strongly with the interstellar medium there. The arch shock is not complete, it is almost invisible in the northwest. The core has three bright lobes to the south and a central opening. "
While the nebula can be easily "picked" in the OIII band, in Ha the nebula itself and the background require many hours of exposure with fast astrograph. I recorded 20 hours in bin 2.
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