Abell 2218 galactic cluster in the constellation Dragon, is about 2.1 billion light years from Earth (cosmological redshift z = 0.17).
The photo shows a set of small yellowish galaxies. For a particular identification of details is very helpful here is this work:
http://iopscience.iop.org/article/10.1086/177995/pdfNo. 289. The brightest and most easily detectable arc. z = 1.03. Visible even on some individual subs.
No. 359 /328. The first is a brighter and more easily detectable red arc, the second is a weaker counter-image of the first arc 359. z = 0.7. The complex itself (plus no. 337/389 visible in the HST image), according to scientists, is an image of a background spheroidal galaxy.
No. 384 /468. The first is still bright, the second is very weak counter-image of the first arc. z = 2.8. The value of the redshift is such that the object will move away from us at a speed of 261,000 km/s, which is already 87 % of the speed of light.
No. 444. Much weaker than its neighbour arc 384. z = 1.1. Magnitude in red 23m.
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