Astrophoto: Ptolemy’s Cluster by Rolf Wahl Olsen

Looking like diamonds in the sky, this lovely astrophoto shows Ptolemy’s Cluster, or Messier 7, a very bright open star cluster easily visible with the naked eye near the tail of Scorpius. Taken by photographer Rolf Wahl Olsen — Sky Viking on Flickr — this beautiful, glittering cluster is about 980 light years away from Earth and has some 80 member stars within its diameter of about 25 light years. Astronomers have determined these young, bright stars are approximately 200 million years old.

The cluster is visible as a hazy patch in the sky, and was first described by the ancient astronomer Ptolemy in 130 AD.

Rolf said this image was taken with a bright 78% illuminated Moon nearby.

Image details:
Date: 31st May 2012
Exposure: LRGB: 48:24:24:24m, total 2hrs @ -28C
Telescope: 10″ Serrurier Truss Newtonian f/5
Camera: QSI 683wsg with Lodestar guider
Filters: Astrodon LRGB E-Series Gen 2
Taken from Sky Viking’s observatory in Auckland, New Zealand

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One Reply to “Astrophoto: Ptolemy’s Cluster by Rolf Wahl Olsen”


    25 light years = 2.365125×10^19 cm. From Complete Unified
    Theory, this distance is like as Avo. No. / root of 2 x Pi^2 x R =
    2.366856×10^19 cm. , where, R = ratio of atom and electron.

    Nirmalendu Das

    Dated: 13-08-2012. Email: [email protected]

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