Drawing the path of celestial bodies
Galaxy NGC 3156 captured by the Hubble Space Telescope. Image source: ESA/Hubble and NASA, R. Sharples, S. Kaviraj, W. Kale
This is like a dream Hubble Space Telescope The Image of the Week shows the galaxy known as NGC 3156. It is a lenticular galaxy, which means it lies somewhere between an elliptical galaxy and a spiral galaxy. It is located about 73 million light-years from Earth, in the small constellation Equatorial Sextile.
The historical importance of the two sextants
The sextant is a small constellation belonging to the Hercules family of constellations. It is itself an astronomically themed constellation, named after the machine known as the sextant. Sextants are often thought of as navigational tools invented in the 18th century. However, the sextant as an astronomical tool has been around for much longer than that: Muslim scholars developed astronomical sextants hundreds of years ago in order to measure angles in the sky.
Ulug Beg Observatory in Samarkand, Uzbekistan. Built by Timurid astronomer Ulugh Beg. Credit: European Space Agency
A particularly striking example is the massive sextant with a radius of 36 metres, developed by Ulugh Beg of the Timurid dynasty in the 15th century, located at Samarkand in present-day Uzbekistan. These early sextants were probably a development of the quarter, a measuring device proposed by Ptolemy. The sextant, as its name suggests, has the shape of one-sixth of a circle, roughly the shape of a constellation.
Modern astronomy and NGC 3156
Sextants are no longer used in modern astronomy, having been replaced by instruments capable of measuring the positions of stars and astronomical objects more precisely and precisely. NGC 3156 has been studied in many ways other than pinpointing its exact location, from its collection of globular clusters, to its relatively recent star formation, to stars being destroyed by the supermassive black hole at its center.
A sextant is a navigational instrument used to measure the angle between a celestial body and the horizon, which helps in determining latitude during sea and air navigation.
More about hexagons
A sextant is a navigational instrument used primarily to measure the angle between a celestial body and the horizon, which aids in maritime and air navigation. This tiny instrument, shaped like one-sixth of a circle, uses a small telescope and reflecting mirrors. By observing the altitude of the stars, sun, or moon, sailors and aviators could determine latitude, and sometimes longitude, relative to the Earth’s surface. Historically, the sextant was useful to explorers and navigators, enabling them to accurately chart their courses over vast, unmarked expanses of ocean or air.
