Abell 2744, also known as Pandora’s Cluster, is a giant pile-up of four smaller galaxy clusters. Abell 2744, and its neighboring parallel field, are among the first targets of the Frontier Fields program.
The Abell catalogue of galaxy clusters was first compiled by astronomer George O. Abell in 1958, with over 2,700 galaxy clusters observable from the Northern Hemisphere. The Abell catalogue was updated in 1989 with galaxy clusters from the Southern Hemisphere.
The planned dates for Hubble observations of the Frontier Fields include observations approximately six months apart. This is the time it takes for the cameras on Hubble to swap positions so that both visible-light data and infrared-light data can be captured from the galaxy cluster field and the adjacent parallel field, as described in this post.
Galaxy Cluster Cosmological Redshift: 0.308
Redshift measures the lengthening of a light wave from an object that is moving away from an observer. For example, when a galaxy is traveling away from Earth, its observed wavelength shifts toward the red end of the electromagnetic spectrum. The galaxy cluster’s cosmological redshift refers to a lengthening of a light wave caused by the expansion of the universe. Light waves emitted by a galaxy cluster stretch as they travel through the expanding universe. The greater the redshift, the farther the light has traveled to reach us.
Galaxy Cluster Distance: approximately 3.5 billion light-years
Galaxy Cluster Field Coordinates (R.A., Dec.): 00:14:21.2, -30:23:50.1
Parallel Field Coordinates (R.A., Dec.): 00:13:53.6, -30:22:54.3
Source – frontierfields.org