ROUTINE SURVEY PHASE

With the spacecraft, telescope, instrument, and processing at full speed, the routine survey begins. There are three main elements to the Euclid Survey; the Wide Survey, Deep Survey and Routine Calibrations. The Wide Survey covers 14,000 square degrees of the extragalactic sky while the Deep Survey consists of three areas of the sky observed to a much greater depth, with a total area of 50 square degrees. The last component are routine calibration observations that monitor the performance of VIS and NISP. This helps understand the measurements made with the observations and the data processing system uses this data to ensure the best use of the science images from the instruments.

Two great circles on the sky are not suitable for the Euclid survey. The first is the Galactic Plane, which obscures the distant galaxies we wish to observe. The second is the Ecliptic Plane, where the planets and minor bodies orbit around the Sun. The Ecliptic Plane contains dust which contaminates the measurements of the galaxies. Both the Galactic and Ecliptic Planes are excluded from the survey, leaving approximately one-third of the sky available for the science of the mission.