Launched on December 19, 2013 the Gaia probe is on a 5 year mission to complete a 3D catalogue of approximately 1 billion celestial objects. Operating from the Sun-Earth L2 Lagrangian point the probe will keep a Lissajous orbital trajectory while examining some 1% of the Milky Way.
In the image above, Gaia imaged the young star cluster NGC1818 as part of calibration and testing before the science phase of the mission begins.
Composed of a field-of-view that is 212 x 212 arcseconds, the image is approximately oriented with north up and east left. The integration time of the image was 2.85 seconds and the image covers an area less than 1% of the full Gaia field of view.
Gaia’s overall design is optimized for making precise position measurements and the primary mirrors of its twin telescopes are rectangular rather than round. To best match the images delivered by the telescopes, the pixels in Gaia’s focal plane detectors are also rectangular.
In order to produce this image of NGC1818, the image has been resampled onto square pixels. Furthermore, to maximize its sensitivity to very faint stars, Gaia’s main camera does not use filters and provides wide-band intensity data, not true-color images. The false-color scheme used here relates to intensity only. The real colors and spectral properties of the stars are measured by other Gaia instruments.
Images Courtesy of ESA
Source: ESA