NGC 7027 in Cygnus

August 2026 - Nebula and Cluster of the Month

August brings with it the welcome return of dark nights and also the best views of the Milky Way of the year from northern climes. Riding high, of course, is the constellation of Cygnus, the Swan. Bursting with emission and reflection nebulae, open clusters and planetary nebulae, it’s a happy hunting ground for deep-sky observers.

The New General Catalogue and Index Catalogue together list eleven planetary nebulae in Cygnus. The two brightest are both around magnitude 10, and one of these is NGC 7027. This object has held a fascination for me for many years because of its unusual morphology, which is easily detected, even in small telescopes.

The object was discovered by French astronomer Édouard Stephan (1837 – 1923 – he of the Quintet) in 1878. He described it as planetary, stellar = 8.5m, which is a little uninspiring. Don’t let that description put you off looking for it. It is not stellar.

An image of the planetary nebula NGC 7027 in Cygnus courtesy of NASA, ESA, and J. Kastner (RIT)
An image of the planetary nebula NGC 7027 in Cygnus courtesy of NASA, ESA, and J. Kastner (RIT)

NGC 7027 has proved to be a very important object for the study of the transition of stars from the Asymptotic Giant Branch stage to the white dwarf stage, for not only is the planetary nebula relatively close (about 3000 light-years), it is also very young (only about 600 years).

Recent research using the Hubble Space Telescope (HST) and the Five-Hundred Meter Spherical Aperture Telescope (FAST), in China, has revealed multiple nested shells, intricate ionisation fronts, knots of dust and a highly structured photodissociation region surrounding the bright, ionised core. All this demonstrates that the complexity seen in the nebula results from several mass-loss events before the central star became hot enough to ionise its surroundings. In other words, this shows how planetary nebulae start to form even before they become visible.

In what seems to be an ever-more common situation, the central star has turned out to be a binary. Planetary nebulae with bipolar morphology (most of them) have binary central stars, and the gravitational interaction between the stars funnels the high-velocity bipolar outflow.

NGC 7027 lies amongst the dense Milky Way stars of Cygnus, 5½° southeast of Deneb. I have been fascinated by this object for many years, maybe because it featured on one of the Astro Card finder charts I mentioned in the article about NGC 1514 (November 2024). I made my first observation of it on 31 August 1980, through my trusty little Japanese 4½” reflector. This shows how much detail can be seen in this ‘stellar’ planetary nebula even with such a small instrument. Although at my usual power of x45 it did indeed look stellar, cranking the power up to x150 revealed remarkable detail.

A sketch of planetary nebula NGC 7027 in Cygnus by Patrick Maloney through his 4½-inch newtonian telescope at x45 and x150 magnification.
A sketch of planetary nebula NGC 7027 in Cygnus by Patrick Maloney through his 4½-inch newtonian telescope at x45 and x150 magnification.

On that night, I wrote NGC 7027 is a bright object, yet difficult to identify simply because of its small size. It can be identified only on the employment of a moderate power, which reveals, on close inspection, a rectangular object, which, in moments of superior seeing, appears to be bisected by a dark line. The nebula is elongated in PA about 45 degrees with the nebula fading off towards the SE.

I have to admit that I was dubious about the ‘dark line’ crossing the nebula for some time. I could find no photographs anywhere near good enough to show whether I had imagined it or not. I looked at it from time to time, and eventually convinced myself that it was real. I visited it again on 23 June 2014.

A sketch of planetary nebula NGC 7027 in Cygnus by Patrick Maloney through his 12-inch newtonian telescope at x450 magnification with an OIII filter.
A sketch of planetary nebula NGC 7027 in Cygnus by Patrick Maloney through his 12-inch newtonian telescope at x150 magnification with an OIII filter.

Once again, the dark bisecting line was clear. I wrote Very bright and very small. It appears rectangular in shape. The northern half is brighter than the southern, with an intense bright spot in the northwest. A dark line bisects the nebula across its shorter dimension, half way along. At x450, the OIII filter reveals a fainter outer nebulosity. The filter does little for the brighter part of the nebula. Stands very high power very well, under which it appears a little more rounded. The western edge is sharper, the eastern edge tending to fade away as if ‘brushed’.

No matter what size telescope you have, NGC 7027 is a rewarding object to look at, revealing considerable detail.

Patrick Maloney

Object RA Dec Type Magnitude
NGC 7027 21h 07m 02s +42° 14’ Planetary nebula 10.4

If you'd like to try out the Clear Skies Observing Guides (CSOG), you can download observing guide for the current Cluster of the Month without the need to register. CSOG are not associated with the Webb Deep-Sky Society but the work of Victor van Wulfen.