APOD: 2026 January 4 – The Einstein Cross Gravitational Lens

Good evening, Rallypoint, and welcome to the January 4, 2026 Astronomy Picture of the Day (APOD). We are looking at The Einstein Cross, a gravitationally lensed quasar that sits directly behind the center of a galaxy known as Huchra's Lens. If you are not familiar with the concept of gravitational lensing, it is worth a few minutes on Wikipedia to learn about it. In simple terms, a mass (such as a galaxy) that lies between a more distant light source and an observer can bend the light waves that emanate from the light source.

Four images of the same distant quasar plus one in the center appear in the middle of the foreground galaxy due to strong gravitational lensing. This system was discovered by John Huchra and coworkers in 1985, although at the time they only detected that there was a quasar behind a galaxy based on differing redshifts and did not resolve the four separate images of the quasar.

While gravitationally lensed light sources are often shaped into an Einstein ring, due to the elongated shape of the lensing galaxy and the quasar being off-center, the images here form a peculiar cross-shape instead.