The Headphone Nebula is a large, low-surface-brightness planetary nebula whose shape becomes especially attractive in deep narrowband images. For astrophotographers, it is much more of a patience target than a brightness target, because the integrated magnitude sounds manageable while the light is spread over a fairly wide area. H-alpha and O III data usually reveal the structure best, while broadband data can struggle unless the sky is very dark and the total integration time is generous. Its faint central star adds a nice extra challenge, but the real reward is pulling out the nebula’s delicate shell and the subtle contrast between the two brighter side lobes.
Names and Catalog numbers
Trivial names: Headphone Nebula, Headphones Nebula, Jones-Emberson 1
Other commonly used catalog numbers: PK 164+31.1, PN G164.8+31.1
Position and the cosmic neighborhood
In the sky, the nebula sits in the northern part of Lynx and is commonly located by star-hopping from 27 Lyncis, lying about 2.5 degrees to its northwest. For imagers, the field is interesting because the nebula is placed well away from the brightest Milky Way star clouds, so the background is not overwhelmingly crowded and very distant background galaxies can show through the frame. A well-composed image often benefits from leaving some surrounding field in place, because the object is not huge and the context helps its “headphone” outline stand out. There is also a historical curiosity in the same neighborhood: NGC 2474 and NGC 2475 lie roughly half a degree to the south and were once incorrectly associated with this nebula.
Nice to Know
It is an astrophotography target far more than a casual visual target. Even though the nebula is often listed around 14th magnitude, its low surface brightness means it usually needs long total exposure time to look impressive.
Narrowband works especially well here. The object responds very nicely to H-alpha and O III imaging, which is why many of the best amateur results are produced in HOO or related narrowband palettes.
The central star is faint but important to the final look. At about magnitude 16.8, it is not the main attraction, yet recording it cleanly gives the image a strong sense of depth and authenticity.
The nebula is uncommon enough to feel distinctive in an imaging portfolio. It is not one of the standard beginner planetary nebulae, so a successful image of PK 164+31.1 tends to stand out among more familiar targets.
Brightnes, distance and size
The Headphone Nebula is usually given an integrated visual brightness of about magnitude 14, but that number can be misleading because the nebula is spread across roughly 6 to 7 arcminutes and therefore has very low surface brightness. Its distance is commonly quoted at about 1,600 light-years. At that distance, an apparent size of around 6.3 to 6.7 arcminutes corresponds to a physical diameter of roughly 3 light-years, though some descriptions round it up to about 4 light-years when the faint outer extent is included. In practical imaging terms, this means it is large enough to show structure with moderate focal lengths, yet faint enough that it benefits strongly from dark skies, careful calibration, and substantial integration time.
