Double solar transit: Mercury and HST
Taken by Thierry Legault on November 11, 2019 @
Machuca, Chile
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Camera Used: Unavailable Unavailable
Exposure Time: Unavailable
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Date Taken: 2019:11:11 20:58:44
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Details:
In 2016, I photographed the International Space Station (ISS) flying in front of the Sun at the same time as Mercury from the Philadelphia area.
For Mercury's November 11 passage, I decided to do something harder, something that was never done. I placed near Machuca (north of San Pedro de Atacama), 4000 m above sea level near a lagoon where flamingos colonies frolic. Calsky predicted a transit of the Hubble Space Telescope visible from there, lasting 0.9s at precisely 11h04m23.8s local. Hubble, at the time of transit, was flying at 26500 km/h, at a distance of 624 km.
Since a week that I am here, the weather has been fine over Atacama. But the clouds took over the sky last night, and it was through a thick layer of high clouds causing a huge diffusion of sunlight and a sharp drop in contrast that I had to adjust the instruments and photograph the double transit, without really believing it. It is only by increasing the exposure time by a factor of 10 (1/3200s against 1/32000s normally) and by pushing the levels and the contrast on the images that I could make appear Mercury and especially Hubble on the dozen images where it is visible.
On the Olympus E-M1, the burst was triggered automatically by a device designed and made at my request by a friend, Emmanuel Rietsch. This box synchronizes to an extremely accurate GPS signal called 1PPS (1 pulse per second) and triggers shooting at the scheduled time.
I add a photo of the spot and the image of the Sun as it appeared on the screen of the camera.
Photographer's website:
https://www.astrophoto.fr
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