The Euclid Survey(s) | In the Dark


Since it’s been a couple of weeks since Euclid commenced its routine survey operations, I thought I would share this little video from the European Space Agency that shows how the surveying will proceed over the next six years with explanatory text adapted from here:

This animation shows the location of the fields on the sky that will be covered by Euclid’s wide (blue) and deep (yellow) surveys. The sky is shown in the Galactic coordinate system, with the bright horizontal band corresponding to the plane of our Milky Way.

The wide survey will cover more than one third of the sky as shown in blue. Other regions are avoided because they are dominated by Milky Way stars and interstellar matter, or by diffuse dust in the Solar System – the so-called zodiacal light. The wide survey is complemented by a deep survey, taking about 10% of the total observing time and repeatedly observing just three patches of the sky called the Euclid Deep Fields, highlighted in yellow.

The Euclid Deep Field North – towards the top left – has an area of 20 square degrees and is located very close to the Northern Ecliptic Pole. The proximity to the ecliptic pole ensures maximum coverage throughout the year; the exact position was chosen to obtain maximum overlap with one of the deep fields surveyed by NASA’s Spitzer Space Telescope.

The Euclid Deep Field Fornax – in the lower right of the image – spans 10 square degrees and is located in the southern constellation Fornax, the furnace. It encompasses the much smaller Chandra Deep Field South, a 0.11 square degree region of the sky that has been extensively surveyed in the past couple of decades with the Chandra and XMM-Newton X-ray observatories, as well as the Hubble Space Telescope and major ground-based telescopes.

The third and largest of the fields is the Euclid Deep Field South – between the Large Magellanic Cloud and the Euclid Deep Field Fornax. It covers 20 square degrees in the southern constellation of Horologium, the pendulum clock. This field has not been covered to date by any deep sky survey and so has a huge potential for new, exciting discoveries. It has been planned to be observed from the ground by the Vera C. Rubin Observatory.

P.S. According to my latest calculations, I shall have retired by the time the Wide survey is completed.

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