MWP1, also catalogued as PK 080–10.1 and PN G080.3–10.4, is a remarkably large and ancient planetary nebula located in the constellation Cygnus. It is commonly referred to as the Methuselah Nebula, a fitting name given its exceptional age.
The nebula was discovered in the 1990s by a team of astronomers: C. Motch, K. Werner, and M. Pakull. The "MWP" in its name comes directly from their initials. They found it while investigating a weak X-ray source, which turned out to be the nebula's exceptionally hot central star
MWP1 lies at an estimated distance of ~4,500 light-years, although Gaia DR3 data suggest a closer value of ~1,630 light-years (502 parsecs). With an apparent size of about 13 arcminutes, this corresponds to a physical diameter between 6 and 15 light-years, making it one of the largest planetary nebulae known.Its structure is distinctly bipolar, with two symmetrical lobes extending from a central region. The central star, now identified as a GW Vir-type pre-white dwarf, is extremely hot (around 150,000 K) and emits strong ultraviolet and even X-ray radiation. This has maintained the nebula’s ionisation for far longer than usual.
What makes MWP1 so fascinating is its estimated age of ~150,000 years, vastly exceeding the typical lifespan of planetary nebulae, which usually fade after 10,000 to 20,000 years. Despite its faintness, it remains optically visible in Hα and O III, offering a rare glimpse into the extended end phases of stellar evolution.
Within the same field recorded by my STL camera lies a second, smaller and more compact planetary nebula, known as Alv1 (PN G079.8–10.2). It was discovered in 2009 by the Portuguese amateur astrophotographer Filipe Alves, during a deep imaging session of MWP1. Further information about this nebula can be found here.
Given the extreme faintness of MWP1, as well as the nearby Alv1, I dedicated a significant amount of exposure time to capture its subtle structure. Between March and July 2025, I collected data using Hα and O III narrowband filters, complemented by some RGB exposures for the stars. The final image was composed using the HOO palette.
All data were acquired remotely using my Takahashi TOA‑150 refractor and SBIG STL‑1000M monochrome CCD camera. I employed Astrodon filters for Hα, R, G, and B, and a Baader filter for O III. The total integration time amounts to 55 hours.
Image Processing
My main objective with this image of MWP1 was to reveal as much structural detail as possible from this extremely faint nebula.
The general processing strategy began by removing the stars using StarXTerminator, allowing the nebular features to be processed independently. The starless image was then treated using the following tools:
NarrowbandNormalization to balance the signal from the Hα and O III channels.
HDRMultiscaleTransform to enhance local contrast and bring out internal structures.
Colour enhancement applied using the Curves tool.
After completing the processing of the nebula, the RGB stars, which had been processed independently to preserve their natural colours, were seamlessly reintegrated using the excellent script developed by Mike Cranfield and Bill Blanshan.
In the case of Alv1, the processing followed essentially the same workflow as described for MWP1. However, given its smaller angular size, I applied drizzle ×2, resulting in an image scale of 0.845″/pixel.
The third image is a wide-field composition showing MWP1 together with Alv1.
Click on the images for full resolution versions, or go to the Gallery section for complete exposure details.
Image processing: Pixinsight.
Observatory automation and remote operation with Talon6.
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