Abell 2218

ABELL2218(500).jpg (82942 bytes)

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ABELL2218(700).jpg (105143 bytes)

Full-resolution crop of the central portion of the image

Galaxy cluster Abell 2218 is located in the constellation Draco, about 2 billion light-years from our own galaxy. The large spiral galaxy at upper right is PGC 58586 (magnitude 15.1), which is a foreground object and not part of the cluster.The mass of the cluster acts as a gravitational lens, magnifying and distorting galaxies lying behind it into arcs, some of which can be seen in the left image below. The image on the right highlights the lensed galaxy images. From left to right, the respective redshift (z), apparent magnitude/magnitude corrected for lensing amplification, and light travel time for each is:

z = 1.0, mag 20.5/22.3, 7.7 billion light-years
z = 0.6, mag 22.2/23.4, 5.7 billion ly
z = 0.18, mag 20.1/20.1, 2.2 billion ly
z = 0.7, mag 20.3/24.9, 6.3 billion ly
z = 2.5, mag 21.2/24.1, 11.0 billion ly

ABELL2218(600).jpg (42390 bytes) ABELL2218(600)Map.jpg (43109 bytes)

200% enlargements of the central portion of the image.

Equipment: Meade 14" LX200R/ST-10XME/Astro-Physics CCDT67 telecompressor/Paramount ME
F-ratio: f/6.5
Exposures: Unfiltered: 31 x 20 minutes, unbinned
Date: June 4 and 5, 2010
Location: Landers, California, USA
Technical Notes: I
ndividual exposures were dithered using CCDAutoPilot2 and then sigma combined. Reduce Noise was applied to the dim portions of the luminance image. A High-Pass filter of 6 pixels was applied to the spiral galaxies near the top of the image.

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