November’s top lunar feature to observe
Montes Carpatus
Type: Mountain range
Size: 300km x 95km
Longitude/Latitude: 23.6o W, 14.7o N
Age: 3.2–3.9 billion years
Best time to see: Two days after first quarter (13–14 November) or one day after last quarter (27–29 November)
Minimum equipment: 50mm refractor
Mare Imbrium (1,250km) is bounded by some impressive mountain ranges. One of them, Montes Carpatus, is located along the mare’s southern edge, to the north of the impressive 93km ray crater Copernicus. Although it lacks the grandeur of the lunar Apenninus, Caucasus and Alpes ranges that define Imbrium’s eastern border, there’s still plenty of interest to see within the Carpatus mountains.
The range runs for approximately 300km in an eastwest line. Its southern flanks have been interrupted by secondary impacts from the formation of Copernicus. This is evident in the eastern section of Montes Carpatus, where small chains of craters can be seen radially aligned to the centre of Copernicus. Two distinct craters can also be seen north of Copernicus, invading the range. The larger one is 27km Gay-Lussac; the smaller, to the southeast of Gay-Lussac, is 14km Gay-Lussac A. Furthermore, immediately north of Gay-Lussac is the irregular shape of 11km x 5km Gay-Lussac D. This appears to border a region where lava has infiltrated the Carpatus mountains, creating a division through the range. This 25km-wide expanse of lava runs from Mare Imbrium almost to the northern edge of Gay-Lussac.
Evidence for the inflow of lava into the Carpatus mountains can be found along the northern edge of the range from the mid-section and further west. There appears to be a linearity to some of the features here, oriented towards Mare Imbrium. As you head west you eventually arrive at the 34km crater T Mayer, named after Tobias Mayer, an 18th-century German astronomer. T Mayer has a flat floor with two small clusters of peaks, one near the southwest rim, one northeast of the crater’s centre. Immediately to the east is the smaller 16km T Mayer A. This has well-defined, wide and steep rims which lead down to a flat floor.
Both craters appear towards the western end of the Carpatus range. West of T Mayer lava wins out, covering most of the mountains to leave just a few solitary peaks poking out. It is worth following the range to its conclusion as this leads to one of the more extreme examples of a flooded crater, T Mayer W. This sizeable feature could be described as an ‘almost’ ghost crater. With a diameter of 34km, virtually all of this feature is hidden under the Imbrium lava. However, the rim to the east is elevated enough to poke demonstrably above the mare’s surface. With good illumination, it’s also possible to see the vague remnant of the rest of the rim. A bright Copernican ejecta ray passes through T Mayer W.
The peaks located to the west and northwest of 9km T Mayer E appear bright when the morning terminator passes over them, producing a roughly triangular appearance unofficially known as ‘Promontorium Banat’. It is in this region that the highest mountain of the Carpatus range is located, its peak rising to the low altitude of 2.1km. As you move your gaze north from here into the dark lava plain of Mare Imbrium, it’s interesting to note the variations in surface brightness. These differences are again mostly caused by the impact ejecta from Copernicus overlaying the darker lava, which fills the mare.