Astrophoto: Ptolemy's Cluster by Rolf Wahl Olsen

By Nancy Atkinson - August 12, 2012 at 4:05 PM UTC | Observing
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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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Nancy Atkinson

Nancy Atkinson

Nancy Atkinson is a space journalist and author with a passion for telling the stories of people involved in space exploration and astronomy. She is currently retired from daily writing, but worked at Universe Today for 20 years as a writer and editor. She also contributed articles to The Planetary Society, Ad Astra (National Space Society), New Scientist and many other online outlets.

Her 2019 book, "Eight Years to the Moon: The History of the Apollo Missions,” shares the untold stories of engineers and scientists who worked behind the scenes to make the Apollo program so successful, despite the daunting odds against it. Her first book “Incredible Stories From Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos” (2016) tells the stories of 37 scientists and engineers that work on several current NASA robotic missions to explore the solar system and beyond.

Nancy is also a NASA/JPL Solar System Ambassador, and through this program, she has the opportunity to share her passion of space and astronomy with children and adults through presentations and programs. Nancy's personal website is nancyatkinson.com