A brilliant hack - Dragonfly (updated)

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I had written about the original back in 2015: A brilliant hack - Dragonfly

Back then, it was an array of ten commercial telephoto lenses synched together.  Much simpler and cheaper to implement than a mirror of that same size. Fast forward to today. From DP Review:

Canon USA is providing 120 EF 400mm F2.8 lenses to expand Dragonfly Telephoto Array
Canon USA has announced that the company will provide technical assistance to Project Dragonfly, an international research team from Yale University and the University of Toronto, in its plan to expand the Dragonfly Telephoto Array.

The Dragonfly Telephoto Array is a telescope concept designed to capture images of extremely faint structures in the night sky. It is believed that the structures offer insight into the distribution and nature of dark matter.

Canon USA will provide the team with 120 Canon EF 400mm F2.8L IS II USM large-aperture super-telephoto lenses. Canon Inc. will also provide technical assistance. The telephoto array currently consists of 48 Canon EF 40mm F2.8L IS II USM lenses given to the team in 2013 and 2015. The lenses are arranged in two clusters of 24. The additional 120 primes will significantly enhance the array's capabilities.

If they tried to do this with a conventional mirrored telescope, the mirror would be 1.8 meters in diameter but with a focal length of only 40cm (400mm).  There are, of course, light losses in any optical system but the theoretical aperture would be F 0.22 - that is a very fast lens (there are some commercial lenses with F 0.9 but they are rare and expensive - here is the fascinating story of one that is F 0.7)   The curvature on a conventional mirror would be prohibitively deep but easy to do with a simple lens - each lens is focused on a CCD sensor and the images are combined and stacked to give a lot better detail of fine structure.

Here is one cluster with 24 lenses:

20211119-dragon.jpg

The scope's home page is here: The Dragonfly Telephoto Array

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This page contains a single entry by DaveH published on November 19, 2021 5:31 PM.

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