Abell 2218  -  A Gravitational Lens

Full resolution (1600x1200 px  550kB)

150% resolution (980kB)

Object identification (590kB)

Identification of arcs created by gravitational lensing (200kB)

DSLR widefield image

Object data of Abell2218

Object type: galaxy cluster
Size: 20'
Magnitude: 17.7 mag (magnitude for the tenth-ranked cluster member)
Constellation: Dra
Distance: 2.1 billion Ly
Notes: Abell 2218 is a cluster of galaxies about 2.1 billion light-years away in the constellation Draco. Acting as a powerful gravitational lens, it magnifies and distorts galaxies lying behind the cluster core into long arcs, as predicted by the General Theory of Relativity.

These arcs are very faint and difficult to capture. The three brightest arcs are visible in a 400% crop of the above image.

Exposure data

Date: 2010-07-02 + 07 + 08 + 09
Location: Nussbach / Austria (400m)
Telescope: 12" Newtonian telescope (f=1120mm)
Camera: ST2000XM with CFW8 and Baader Filters
Binning: L 1x1 / RGB 1x1
Exposure time: L 36x12m / R 9x12m / G 9x12m / B 9x12m
Exposure time total: 12h 36m