Promontorium ( / ˌ p r ɒ m ə n ˈ t ɔːr i ə m/) – cape.

Fastigium ( / f æ s ˈ t ɪ dʒ i ə m/) – summit.

Depressio ( / d ɪ ˈ p r ɛ ʃ i oʊ/) – lowland.

Cornu ( / ˈ k ɔːr nj uː/) – horn, peninsula.

These are generally, but not always, second in the name, but are usually ignored in alphabetizing below: Several Latin words involved here are common nouns.

In addition, since most Earth-based amateur telescopes are not powerful enough to resolve the topographic surface features of Mars, amateur astronomers still use many of the old feature-names to orient themselves and record their observations.Ĭlassical albedo features on Mars, whose names date back to Schiaparelli (1888 map above) share some boundaries with more recent satellite observations. However, many of the names used for topographic features on Mars are still based on the classical nomenclature for the feature's location for instance, the albedo feature 'Ascraeus Lacus' provides the basis of the name of the volcano Ascraeus Mons in roughly the same position. The pictures returned by interplanetary spacecraft, notably the observations made from Martian orbit by Mariner 9 over the course of 1972, have revolutionized the scientific understanding of Mars, and some of the classical albedo features have become obsolete as they do not correspond clearly with the detailed images provided by the spacecraft. This involved a considerable amount of pruning Antoniadi's La Planète Mars had mentioned 558 named features.

Of these, 105 came from Schiaparelli, 2 from Flammarion, 2 from Percival Lowell, and 16 from Antoniadi, with an additional 3 from the committee itself. In 1958, the International Astronomical Union set up an ad hoc committee under Audouin Dollfus, which settled on a list of 128 officially recognised albedo features. However, there was still no 'official' system of names for Martian features. In his encyclopedic work La Planète Mars (1930) Antoniadi used all Schiaparelli's names and added more of his own from the same classical sources. Antoniadi took over as the leading telescopic observer of Mars in the early 20th century, he followed Schiaparelli's names rather than Proctor's, and the Proctorian names quickly became obsolete. This variability may explain many of the differences between telescopic observations over the years.Įarly map by Flammarion and Antoniadi. The dust-storms themselves also appear as light patches, can cover vast areas and sometimes last for many weeks when Mariner 9 arrived in Martian orbit in November 1971 the entire planet was covered by a single enormous dust-storm, with only the peaks of the four or five highest mountains showing above it. They are now known to be areas where the wind has swept away the paler dust, exposing a darker surface, often basaltic rock so their borders change in response to windstorms on the Martian surface that move the dust around, widening or narrowing the features. The dark features were then thought by some to be indications of Martian vegetation, since they changed shape and intensity over the course of the Martian year. Within a few decades, however, most astronomers came to agree that Mars lacks large bodies of surface water. When Giovanni Schiaparelli began observing Mars in 1877, he believed that the darker features were seas, lakes, and swamps and named them accordingly in Latin ( mare, lacus, palus etc.). The lighter patches at the poles were correctly believed to be a frozen substance, either water or carbon dioxide, but the nature of the dark patches seen against the general reddish tint of Mars was uncertain for centuries. The origins of the albedo contrasts were a mystery. These lighter and darker patches rarely correspond to topographic features and in many cases obscure them. North is at the bottom, as seen through an inverting telescope.Įarly telescopic astronomers, observing Mars from a great distance through primitive instruments (though they were advanced for their day), were limited to studying albedo contrasts on the surface of the planet. Proctor's map of Mars, which named albedo features after astronomers.

Nodus feature list