The galaxies in Hubble’s Frontier Fields project are so far away that they cannot be seen with either your eyes or a backyard telescope. It takes a state-of-the-art telescope like Hubble, Spitzer, or Chandra to collect enough of the scant photons streaming in from the most distant galaxies to produce a scientifically valuable image. In fact, Hubble’s views of the Frontier Fields, coupled with the natural lensing power of the galaxy clusters, allow astronomers to potentially detect objects that are 40 billion – yes, billion – times fainter than your eyes can see.
The galaxies in the Frontier Fields are so far away that they appear absolutely tiny in the night sky, even to Hubble. Hubble has the exquisite ability to resolve tremendously small features on the sky and discern details that would otherwise be blurred beyond recognition. If prior deep field observations are any indication, Hubble will observe thousands of galaxies in an area approximately the size of a pin-prick in a piece of paper held up at arm’s length.
The 12 Frontier Fields are located at six positions in the sky. You may not be able to see the Frontier Fields galaxies, but you can still find the area of the sky where they are located using the graphic below.
The map above uses a coordinate system familiar to astronomers. Right Ascension is similar to longitude in that it measures the position of an object east or west of a reference position. Right Ascension is measured in hours, from 0 to 24 hours, with the reference position set at 0 hours. Declination is similar to latitude. It measures the position of an object, in degrees from 0 to 90, north or south of a reference position. The reference position (0 degrees) for declination is the celestial equator, which is the projection of Earth’s equator onto the sky. In this particular map we have truncated declination at 70 degrees north and south.
The Frontier Field’s site map (above) is a representation of the sky on a rectangular grid. When we view the sky from the surface of the Earth, it appears as the interior surface of a hemisphere, or dome — half of what people in ancient times referred to as the “celestial sphere” surrounding the Earth. Just as there are distortions when map-makers make a rectangular map of the spherical Earth, there are distortions in projecting the celestial sphere onto a rectangular grid. Constellations located near the northern and southern celestial poles (90 degrees north and south in declination) are represented on the map as spanning more of the sky than they actually do.
To help find the locations of the Frontier Fields, zoomed-in regions of the six pointings are shown below:
1) Abell 2744
2) MACS J0416
3) MACS J0717
4) MACS J1149
5) Abell S1063
6) Abell 370
For more tips and information about observing the night sky, including access to free monthly sky charts, visit the NASA Night Sky Network. For monthly highlights of interesting objects to observe in the night sky, visit Hubblesite’s Tonight’s Sky.