This video compares the angular size of the XDF field to the angular size of the full Moon. The XDF is a very small fraction of sky area, but it provides a "core sample" of the heavens by penetrating deep into space over a sightline of over 13 billion light-years. Several thousand galaxies are contained within this small field of view. At an angular diameter of one-half degree, the Moon spans an area of sky only one-half the width of a finger held at arm's length.
Illustration: NASA, ESA, G. Bacon, and Z. Levay (STScI);
Image: T. Rector and I. Dell'Antonio (NOAO/AURA/NSF), Digitized Sky Survey (DSS), STScI/AURA, Palomar/Caltech, and UKSTU/AAO;
Science: NASA, ESA, G. Illingworth, D. Magee, and P. Oesch (University of California, Santa Cruz), R. Bouwens (Leiden University), and the HUDF09 Team)
Publication: September 25, 2012