D'Antu à Yepun, la construction du VLT
L'ESO a cinquante ans cette année, pour célébrer cet anniversaire important nous allons vous montrer des morceaux de notre histoire. Une fois par mois durant 2012, une Photo de la Semaine comparant le Passé et le Présent montrera comment les choses ont changé durant les décennies au observatoires de La Silla et de Paranal, les installations ESO à Santiago du Chili et le Siège Social à Garching / Munich, Allemagne.
Le Very Large Telescope VLT, l'installation principale sur Cerro Paranal au Chili, est constitué de quatre Unit Telescopes (UTs) géants, chacun contenant un miroir de 8.2 mètres de diamètre, et de quatre Auxiliary Telescopes (ATs) mobiles de 1.8 mètres. Les deux photos de cette semaine montrent un Unit Telescope en construction et durant les jours actuels.
Le début des travaux sur le dôme du premier Unit Telescope (UT1) peuvent être vus dans cette image historique, prise vers la fin d'Octobre 1995. Les fondations en béton étaient finies et la partie inférieure du dôme y a été fixé. Les premières pièces de la partie tournante du dôme du télescope étaient également déjà mis en place, le début de la grande ouverture de laquelle le télescope observera et la lourde structure horizontale qui supporte les portes coulissantes peuvent être vus sur l'image. Le Unit Telescope a vu le jour le 25 Mai 1998 (Voir eso9820).
À l'inauguration de Paranal en 1999 (Voir eso9921), chaque UT a reçu un nom dans la langue de la tribu Mapuche. Les noms, Antu, Kueyen, Melipal et Yepun pour les quatres UTs allant de un à quatre, représentent quatre beaux et fameux aspects du ciel: Le Soleil, la Lune, la constellation de la Croix du Sud et Vénus [1] respectivement.
La photo de notre époque est celle de l'UT4, Yepun, qui a vu le jour en Septembre 2000 (Voir eso0028). Toutefois, elle sert, tout aussi bien que son jumeau UT1, à montrer la structure achevée du VLT car tous les UTs sont identiques. Seuls les instruments sur chacun d'eux sont différents ce qui donne aux astronomes une large gamme d'outils pour étudier l'univers. La structure jaune devant Yepun est la plate-forme de levage M1, qui peut être bougée entre les différents UTs et est utilisé lorsque les miroirs primaires géants de 8.2 mètres sont enlevés et revêtus périodiquement.
Durant les années après la photo historique, le premier des UTs a trouvé un nom, Antu, et une famille lorsque les autres télescopes l'ont rejoint au sommet de cette montagne. Aujourd'hui le VLT est le télescope astronomique le plus performant en lumière visible au monde, et Antu, Yepun et les autres télescopes de Paranal ont joué un rôle crucial pour faire de l'ESO l'observatoire terrestre le plus productif du monde!
Notes
[1] Yepun a été traduit comme "Sirius" au moment de l'inauguration de Paranal, mais après une investigation supplémentaire la traduction correcte semble être "Vénus".
Liens
- L'image historique
- L'image actuelle
- Composite côte-à-côte de l'image historique et actuelle
- Plus sur le Very Large Telescope de l'ESO
Crédit
À propos de la comparaison d'images
| Identification: | potw1249a |
| Date de publication: | 3 décembre 2012 10:00 |
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