Left: The locations of Hubble’s observations of the MACS J0416 galaxy cluster (right) and the adjacent parallel field (left) are plotted over a Digitized Sky Survey (DSS) image. The blue boxes outline the regions of Hubble’s visible-light observations, and the red boxes indicate areas of Hubble’s infrared-light observations. A scale bar in the lower left corner of the image indicates the size of the image on the sky. The scale bar corresponds to approximately 1/30th the apparent width of the full moon as seen from Earth. Astronomers refer to this unit of measurement as one arcminute, denoted as 1′. Right: Hubble’s view of the galaxy cluster is displayed using archival visible-light observations. Deeper Frontier Fields observations of MACS J0416 are ongoing. Left Credit: Digitized Sky Survey (STScI/NASA), and Z. Levay (STScI). Right Credit: NASA, ESA, M. Postman (STScI), and the CLASH team. extracted from https://frontierfields.org/meet-the-frontier-fields/macsj0416/ June 18, 2018 Estimated Dates of Observations: January-February 2014 and August-September 2014 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 Redshift: 0.396 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 4 billion light-years Galaxy Cluster Field Coordinates (R.A., Dec.): 04:16:08.9, -24:04:28.7 Parallel Field Coordinates (R.A., Dec.): 04:16:33.1, -24:06:48.7 Constellation: Eridanus