Zones du ciel les plus affectées par les constellations de satellites
Sur cette image annotée figure le ciel nocturne surplombant l’Observatoire Paranal de l’ESO à l’aube, quelque 90 minutes avant le lever du Soleil. Les cercles de couleur bleue indiquent la hauteur au-dessus de l’horizon.
Une nouvelle étude de l’ESO consacrée à l’impact des constellations de satellites sur les observations astronomiques révèle qu’une centaine de satellites seraient suffisamment brillants pour être visibles à l’oeil nu lors des phases crépusculaires (magnitude 5-6 ou inférieure). La plupart d’entre eux, entourés de petits cercles de couleur verte sur l’image, se situeraient à moins de 30 degrés au-dessus de l’horizon et/ou seraient relativement peu lumineux. Quelques autres, entourés d’un cercle de couleur rouge, se situeraient à plus de 30 degrés au-dessus de l’horizon – dans cette zone du ciel faisant l’objet de la plupart des observations astronomiques – et seraient relativement brillants (magnitude 3-4). A titre comparatif, Polaris, l’Etoile Polaire, est caractérisée par une magnitude égale à 2 : elle est 2,5 fois plus brillante qu’un objet de magnitude 3.
Le nombre de satellites visibles chute vers le milieu de la nuit, à mesure qu’ils entrent dans l’ombre de la Terre, cette zone sombre occupant la gauche de l’image. Les satellites situés dans l’ombre de la Terre sont invisibles.
Crédit:ESO/Y. Beletsky/L. Calçada
À propos de l'image
| Identification: | eso2004a |
| Langage: | fr-ch |
| Type: | Simulation |
| Date de publication: | 5 mars 2020 09:00 |
| Communiqués de presse en rapport: | eso2004 |
| Taille: | 9000 x 9000 px |
À propos de l'objet
| Nom: | Very Large Telescope |
| Type: | Unspecified : Technology : Observatory |
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