Sh2-290 (also known as Abell 31 or PK 219+31.1) is an ancient planetary nebula in the constellation of Cancer. It is estimated to be about 2,000 light years away.
Although it is one of the largest planetary nebulae in the sky, it is not very bright. The central star of the planetary nebula is a white dwarf with a spectral type of DAO. A planetary nebula is created when a low-mass star blows off its outer layers at the end of its life. The white dwarf is the dead remains of a star that existed but had died leaving behind Sh2-290. This is exactly what is expected of our star when it runs out of fuel in about 5 billion years.
Sh2-290 is made mostly of hydrogen and oxygen gas. The red gas signifies hydrogen gas, and the greenish hues signify the oxygen gas. The nebula has a bright central region being most of the nebula and a red ring around this blue/green region. The nebula, due to its ancient age, has its gas being dispersed into the interstellar medium.
This image was captured over five nights in January 2025. The image consists of 192 exposures, each lasting 5 minutes. These were taken with an f/8 RC8 telescope at 1626mm fl. An asi071MC color camera, cooled to 15f, was used atop a Skywatcher Eq6r pro mount. Image acquisition using Astro Photography Tool (APT) and processed manually in PixInsight.
