NGC 1501

NGC 1501 (also known as the Camel's Eye Nebula or the Oyster Nebula ) is a complex planetary nebula located in the constellation of Camelopardalis, it was discovered on 27 August 1787 by William Herschel.

Properties
The central star of the planetary nebula has a spectral type of [WC4], similar to that of a carbon-rich Wolf–Rayet star. It is a pulsating star, meaning that its brightness varies regularly and periodically. In the case of NGC 1501's progenitor star, this is incredibly fast, with the star's brightness changing significantly in just half an hour. An analysis of Gaia data suggests that the central star is a binary system. Visible-light observations capture the glow of gases including hydrogen and nitrogen. The total mass of the nebula is estimated to be around, most of which is ionized gas and a small fraction  is carbon-rich dust.