Musca. It is southwest of γ Muscae (Gamma Muscae) and west of the southern end of the Dark Doodad Nebula (Sandqvist 149), a 3° thin streak of black across a southern section of the great plane of the Milky Way.- Musca (Wikipedia)
Musca (Latin for ‘“the fly”’) is a small constellation in the deep southern sky. It was one of 12 constellations created by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman, and it first appeared on a celestial globe 35 cm (14 in) in diameter published in 1597 (or 1598) in Amsterdam by Plancius and Jodocus Hondius. The first depiction of this constellation in a celestial atlas was in Johann Bayer’s Uranometria of 1603. It was also known as Apis (Latin for ‘“the bee”’) for 200 years. Musca remains below the horizon for most Northern Hemisphere observers.
- Foliation (geology) (Wikipedia)
Foliation in geology refers to repetitive layering in metamorphic rocks. Each layer can be as thin as a sheet of paper, or over a meter in thickness. The word comes from the Latin folium, meaning “leaf”, and refers to the sheet-like planar structure. It is caused by shearing forces (pressures pushing different sections of the rock in different directions), or differential pressure (higher pressure from one direction than in others). The layers form parallel to the direction of the shear, or perpendicular to the direction of higher pressure. Nonfoliated metamorphic rocks are typically formed in the absence of significant differential pressure or shear. Foliation is common in rocks affected by the regional metamorphic compression typical of areas of mountain belt formation (orogenic belts).