La discussion par Kummer d’une quadrature sur la réfraction astronomique : commentaire historique

Abstract

In an 1860 memoir, Kummer (1810–1893) discusses analytically the consequences of light rays’ quadrature in a spherically symmetrical medium. This fertile approach is illustrated here by showing its graphical translation using the Young–Kattawar diagram (1998). A detailed classification of occuring phenomena is derived for the case of vision through a steep inversion layer: e.g. hillingar and hafgerdingar effects, multiple horizons. These considerations help discussing the corrections which are essential for an accurate astronomical navigation, including horizon’s depression.

Keywords

• Diagramme de Young–Kattawar
• Inversion raide
• Chenal optique
• Niveau d’accumulation
• Effet <i>hillingar</i>
• Dépression de l’horizon
• Courbe de transfert