Observation by Steve Barrett: Ancient Light

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Steve Barrett


Steve Barrett


2020 Jul 21 - 01:00


2021 Feb 25 - 12:04



  • Nikon D7500 DSLR
  • Nikon 300mm f/4 lens
  • iOptron SkyTracker

256 x 30s


Wirral, England

Target name

Quasar PS1 J161737+595020


Ancient Light

About this image


"Remember to look up at the stars and not down at your feet" [Stephen Hawking]. In 2020 I set myself a lockdown challenge, not just to look up, but to look up as far as possible. What is the most distant object that I can photograph with a camera but without using a telescope? The bottom left inset shows the camera and telephoto lens on a star tracker. The rectangle in the top left inset shows the field of view in the constellation of Draco. The main image is a two-hour exposure (taken as 256 x 30s exposures) that shows the fifth-magnitude star AT Dra at the centre. Close by, as shown in the top right inset, is the quasar identified by the two grey lines. At a distance of 25 billion light-years, it is barely one pixel in the image. The quasar is receding from us at twice the speed of light and the light-travel time was over 12 billion years (90% of the age of the Universe). The light from the quasar formed just one pixel in the image ... but what a journey! More details here: https://www.liverpool.ac.uk/~sdb/Astro/Ancient-Light-JBAA.pdf.

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Robin Leadbeater
Robin Leadbeater, 2021 Apr 08 - 19:32 UTC
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