Astrophotographer Kevin Boardman has produced a striking image of the Crescent Nebula, exposing the complex gas filaments enveloping a dying massive star approximately 4,700 light-years from Earth in the constellation Cygnus.
The photograph highlights a critical phase in the lifecycle of Wolf-Rayet star WR 136 (also catalogued as HD 192163). Visible as a blue pinpoint of light at the nebula’s center, the star is on track to explode as a supernova in roughly 100,000 years. According to NASA, the 25-light-year-wide structure consists of stellar material ejected as the star transitioned into a red giant. Subsequent high-speed stellar winds have driven shockwaves through this outer shell, generating the intricate filamentary patterns observed today.
Officially designated NGC 6888 or Caldwell 27, the nebula derives its common name from its crescent-like shape when viewed through specific light wavelengths. To reveal such fine detail, Boardman employed narrowband filters over a total exposure time of 16 hours and 18 minutes, distributed across five nights in late July.
Boardman utilized a ZWO ASI533MC Pro camera, a device noted for its high quantum efficiency and lack of amp glow. He dedicated approximately 12 hours to capturing data from the nebula itself and another 4 hours and 20 minutes on the surrounding star field. The final image combines H-alpha data, which renders orange-red tangled filaments, with [O III] data, which highlights blue-cyan emission from doubly ionized oxygen around the shell.
While the nebula is too faint for naked-eye observation, it remains visible through moderate to large telescopes fitted with light pollution filters during September. Observers can locate it by finding Sadr, the magnitude +2.34 star at the heart of the cross-shaped Cygnus constellation, and then positioning between it and the dimmer magnitude +4.03 star Eta Cygni.
The best viewing conditions occur on dark nights surrounding the new moon phase on September 10-11. For those interested in replicating such imagery, Space.com recommends reviewing their guides on astrophotography equipment and telescopes.
Seventeen hours of exposure is wild dedication. The filament detail really pays off though.
I had no idea WR 136 was only 100,000 years from exploding. That’s practically tomorrow in cosmic time!