Star Chart 2 with Leo, Cancer, Perseus, Gemini, Taurus, Orion etc. circa 1860

Antique star map first published by A.K.Johnston. This map illustrates the visible stars and constellations in the northern hemisphere circa 1860 . The celestial coordinates are shown on the right ascension and declination. The magnitude of the stars in a particular constellation, their brightness as it appears as observed from a location on earth, are labelled according to the Bayer system - 24 letters of the Greek alphabet, from Alpha to Omega, with alpha being the brightest on a descending scale thereafter. In 1603 it was Johann Bayer, a German celestial cartographer, who first used the Greek alphabet for labelling the brightness of stars in a constellation in star cartography. In his star atlas ‘Uranometria’ every star in a constellation was given a letter from the Greek alphabet depending on its apparent brightness from the Earth, or its magnitude. There are 24 letters from Alpha to Omega, with alpha being the brightest. The size of the star illustrated on the maps published here is also indicative of its magnitude based on a scale of 1- 5. The largest illustrated star is the brightest with a magnitude of 1. The ecliptic line details the path of the sun across the sky over the course of a year. 'Neb' refers to the clouds of interstellar matter known as nebulae.

21st century Astronomer’s define a stars brightness in terms of magnitude – how bright the star appears from earth, and absolute magnitude or luminosity – how bright the star appears at a standard distance of 32.6 light years. In 150 BC Greek astronomer Hipparchus was the first to make a catalogue of stars according to their brightness on a magnitude scale of 1 – 6, with 1 being the brightest, but the apparent brightness of a star depends on the location of the observer and distance from the star. Stars that are closer to the Earth but fainter, could appear brighter than far more luminous ones far away. Absolute magnitude measures the luminosity of the star – the power of the star – the amount of energy (light) that star admits from its surface, recorded from an equal distance away without any extinction of the stars light by interstellar dust along the line of sight of the observer, for example.

Please see our blog www.foldingmaps.co.uk/blog/mapping-the-stars for further details.

When this map was published:

Zodiac Constellations are constellations that lie along the plane of the ecliptic.The earliest recorded star list was created by the Babylonians around 1000 BC. It contains around 71 stars and constellations with their associated deity, along with their rising and setting times. It also catalogues the constellations that follow the path of the ecliptic. The ecliptic is the apparent path of the Sun in the Earth’s sky that the sun takes over the course of one year; from another view point, the projection on the celestial sphere of the orbit of the Earth around the Sun. At certain points over the year the sun appears in each of the 13 constellations that fall along the ecliptic line and it is these constellations that astronomers recognise as the zodiacal constellations. As most of the constellations through which the Sun passes represent animals, the ancient Greeks called its zone the “circle of little animals”. Astrologers use 12 of these constellations as signs of the zodiac, omitting Ophiuchus, and unlike astronomy, astrology is not based on scientific fact.
Zodiacal Constellations -
Leo - The Lion. There are a number of luminous galaxies within Leo, including the Leo triplet of M66, M65, and NGC 3628. In Greek mythology, Leo is the Nemean Lion, killed by Hercules.
Cancer - The Crab. The constellation contains the Beehive Cluster, a small star cluster that resembles a swarm of bees.
Perseus - In Greek mythology Perseus was a hero who slayed the Grogon Medusa, who ad snakes for hair and whose gaze turned men to stone. The Perseus constellation contains the Algol star, also known as the Demon Star. This star is said to depict the head of Medusa.
Gemini - Twins. The two brightest stars in the constellation Castor and Pollux represent the heads of twins by the same name in Greek mythology. It also contains The Eskimo nebula, also known as the Clownface Nebula, discovered by William Hershel in 1787.
Taurus - The Bull. One of the oldest documented constellations, with descriptions of Taurus going back to the early Bronze Age. The red star Aldebaran is the eye of Taurus.

Popular Constellation -
Orion - The Hunter. Orion is on the celestial equator and it's position means it is visible across the world from both the North and South Hemisphere. It is one of the brightest and best known of the constellations, along with the Orion Nebula which can be easily seen through small binoculars. The three bright stars that form Orion's Belt - Alnitak, Alnilam, and Mintaka - are also known as the Three Sisters or the Three Kings.