M27
M 27 · Dumbbell Nebula — the first planetary nebula ever found
When Charles Messier noted an oval patch in the constellation Vulpecula on July 12, 1764, he catalogued — without knowing it — an entirely new class of object: M 27 was the first planetary nebula ever discovered. The misleading class name came later from William Herschel, to whom such round little disks in the telescope resembled planets. The Dumbbell has nothing to do with planets — it is the end of a star.
More precisely: the end of a star like the Sun. In its final giant phase a Sun-like star sheds its outer shells; what remains is the hot, compact core as a young white dwarf. Its hard ultraviolet radiation makes the drifting shell glow — for a few tens of thousands of years, after which the gas is dispersed and the light source too cool. What shines here at a distance of about 1,300 light-years is therefore not a place but a brief moment: the Dumbbell is roughly ten thousand years old and still growing.
The colors are a map of ionization. The turquoise interior is doubly ionized oxygen — [O III] glows where the central star's radiation arrives hardest. The red fringe along the long sides is recombining hydrogen at the cooler edge of the shell: the same layering as in the large H II regions of this gallery, only driven by a single dying star instead of young O stars.
The dumbbell shape is a viewing angle. In space M 27 is probably not a bone but rather an hourglass: the shell escapes preferentially along one axis, and we look roughly onto its equator. Seen from the poles, the same nebula would be a ring — the kinship with the Ring Nebula M 57 is not coincidence but geometry.
The culprit stands inconspicuously in the middle. At the center sits the white dwarf as a pale point of about 14th magnitude (marked in the overlay): the size of Earth, carrying a substantial fraction of a solar mass, and still glowing hot. It fuses nothing any more — it merely cools while the shell it cast off drifts away as a cosmic smoke cloud. For the Sun, this very image is the preview of about seven billion years from now.
Where in the sky
The rectangle is this image's real field of view, with its measured rotation — not a symbol. Constellation figures and star positions come from SIMBAD.
2 entries sit within 24° of each other here — click a field to jump to it.
Crops
The dumbbell in detail
The dumbbell in detail — turquoise core, red ears
9.0′ × 10.0′·19h 59m 37.68s +22° 43′ 13.0″
The two-part structure is almost tangible here: the bright turquoise interior is the [O III] zone around the central star, the reddish “ears” along both long sides are the hydrogen fringe of the shell — cooler outside, more harshly irradiated inside. The soft arcs above and below are the fainter polar caps of the presumed hourglass.
The central star sits as an inconspicuous point in the middle of the turquoise; the overlay marks it. That the cause of it all nearly vanishes in its own nebula is the normal case for planetary nebulae — the shell gets the limelight, the star gets the bill.
Milky Way field in Vulpecula
The surroundings — a Milky Way field in Vulpecula
10.1′ × 7.0′·19h 59m 11.40s +23° 03′ 15.8″
M 27 stands right in the band of the summer Milky Way, and this crop shows the backdrop: a dense field of foreground and background stars in every color of the temperature ladder — bluish hot, yellowish Sun-like, orange-red cool.
The four diffraction spikes of the bright field star, by the way, are a signature of the instrument, not of the sky: they arise at the secondary-mirror spider of the Newtonian telescope. Refractor images in this same gallery show stars without these crosses.
Acquisition and processing
The image comes from this gallery's Newtonian era around 2016: a GSO Newtonian and an astro-modified Canon EOS 70D. The caption burned into the processing of the time (upper left in the full image) states 1,000 mm focal length at a 5.82 µm pixel pitch — probably a resampled figure from the software of that era. The original exposure sequences and logs no longer survive; frame counts and total exposure are therefore neither reconstructed nor guessed.
What survives is a 32-bit version reworked for the gallery in 2026. The published file measures 2,780 × 1,853 pixels and is a crop of the original field. The red-and-turquoise separation of the nebula is a property of the object (an Hα fringe around an [O III] core), not narrowband processing — the exposure was broadband with a color sensor.
The published file was independently solved astrometrically in 2026: 1125 Gaia reference stars, residual 0.34″, scale 1.048″/pixel, field 0.81 × 0.54°. Crop coordinates, size figures and all object markers are computed from this solution rather than laid onto the preview by eye.