Gaia calibration image. A Gaia test image of the young star cluster NGC 1818 in the Large Magellanic Cloud, taken as part of calibration and testing before the science phase of the mission begins. The field-of-view is 212 x 212 arcseconds and 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 optimised 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 then also rectangular. In order to produce this image of NGC 1818, the image has been resampled onto square pixels. Furthermore, to maximise its sensitivity to very faint stars, Gaia’s main camera does not use filters and provides wide-band intensity data, not true-colour images. The false-colour scheme used here relates to intensity only. The real colours and spectral properties of the stars are measured by other Gaia instruments.
Read the full press release on ESA's website.
In 1998 the cluster featured in the image was the focus of an Institute of Astronomy/Hubble Space Telescope press release, led by Becky Elson (see Hot White Dwarf Shines in Young Star Cluster). You may find more information about the cluster at NGC1818: Pick a Star on Astronomy Picture of the Day website.
Download the image (JPEG image, 682 KB).
Page last updated: 12 December 2015