Gaia media: a selection

I've included just a few images related to the Gaia satellite, and to the data processing

(the ESA www pages have many more)

along with some of the early scientific and technical meetings.

[For the gallery images, double click for the slide viewer; navigate with left/right arrows; captions are given below them]

Assembling the M1 mirror on the silicon carbide torus (EADS Astrium)

The CCD focal plane (ESA)

Satellite Soyuz launch, French Guiana, 19 December 2013

Assembling the M1 mirror on the silicon carbide torus (EADS Astrium)

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The Gaia satellite under construction

Early Data Release 3 (Dec 2020): catalogue sky plots and statistics [a selection from the ESA archive]

Early Data Release 3: density counts

Density counts for sources with a 5-parameter solution from EDR3 (Galactic coordinates). Densities range from around 100 (light blue) to some 10,000 (dark red) stars per square degree (ESA)

Early Data Release 3: position errors

Median right ascension error for sources with a 5-parameter solution from EDR3 (Galactic coordinates). These range from below 50 micro-arcseconds (dark blue) to about 300 micro-arcseconds (dark red) (ESA)

Sky coverage due to the scanning law

Sky coverage from Data Release 1

Early Data Release 3: density counts

Density counts for sources with a 5-parameter solution from EDR3 (Galactic coordinates). Densities range from around 100 (light blue) to some 10,000 (dark red) stars per square degree (ESA)

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The accuracy of star positions through history. It shows the numbers of stars measured, the technologies used (top), some reference quantities (right), and some of the scientific breakthroughs achieved along the way [pdf version here]

A figure from ESA showing the number of refereed publications per year resulting from its various scientific programme missions over the years 2001–2020. The scientific impact of Gaia is evident from these statistics.

Hipparcos animations

Three 'historical' animations constructed from the Hipparcos catalogue results on the Hyades star cluster. The fields are 8 x 6 degrees. The first shows the proper motions extended over 60,000 years. The second shows a (looped) 'swing' video illustrating the (exaggerated) individual stellar parallaxes (with nearer stars oscillating more than the more distant). The third shows the combination of both proper motions and parallaxes, schematically illustrating how the relative stellar positions change with time. The same principles apply to the Gaia observations. The bright foreground star (moving 'downwards') is Aldeberan [Michael Perryman & Jos de Bruijne]

Three 'historical' animations constructed from the Hipparcos catalogue results on the Pleiades star cluster. The fields are 8 x 6 degrees. The first shows the proper motions extended over 150,000 years. The second shows a (looped) 'swing' video illustrating the (exaggerated) individual stellar parallaxes (with nearer stars oscillating more than the more distant). The third shows the combination of both proper motions and parallaxes, schematically illustrating how the relative stellar positions change with time [Michael Perryman & Jos de Bruijne]

Hipparcos stereo images

These two 'historic' stereo image pairs, constructed from the Hipparcos catalogue, hint at the information contained in the vast Gaia catalogue. They are designed for 'cross-eyed' viewing, with the left image placed to the right, and vice versa. The resulting stereo effect shows how the stars are really distributed in space. The areas of the sky covered are eight by six degrees for each. Sizes are shown according to the star brightnesses, and the colours reflect their temperatures, with white corresponding to hotter stars, and red to cooler.

To view the stereo pairs, concentrate on the images from a distance of around arm's length, although a little closer or further might work better. The idea is to focus the eyes on the page, but to `cross' the eyes so that the right eye looks at the left image, and vice versa. Give some time for the two images to merge into one, and bear in mind that the bright stars in both fields are in the foreground, such that they will be seen `hanging' in front of the paper. Once you have figured out the effect, which may take some minutes the first time, it can usually be repeated again rather easily.

The Hyades star cluster lies at a distance of about 40 parsec or about 130 light-years. The brightest star, just to the above left of centre, is the foreground star Aldebaran.