Diagram showing the spectral class and luminosity of stars
Diagram showing the spectral class and luminosity of stars. The diagram was named The Hertzsprung-Russell Diagram, or the H-R diagram for short. At the beginning of the 20th century two astronomers found that if stars were plotted on a diagram with their luminosity (brightness) on one axis, and their spectral class on the other, that stars formed three distinct groups. The largest group, the Main Sequence Stars, is where 90% of the stars are found. These stars are fusing hydrogen into helium in their cores. This group propagates diagonally from the upper left corner, down to the right corner. The group below the main sequence is the White Dwarfs, which is a group of small, earth-sized stellar remnants. The third group, which is found above the main sequence is that of the giants.
Stars appear on a specific place on the main sequence depending on their mass and age. The mass determines when it will leave the main sequence.The H-R diagram is a significant tool for astronomers, when it comes to understanding stellar evolution.
© Fahad Sulehria/Stocktrek Images
Map of the Course of the River Clyde, England Victorian Engraving, 1840
Very Rare, Beautifully Illustrated Antique Engraving of Map of the Course of the River Clyde, England Victorian Engraving, 1840 from Our Own Country, Great Britain, Descriptive, Historical, Pictorial. Published in 1880. Copyright has expired on this artwork. Digitally restored.
1840 1849, 19th Century, 19th Century Style, 583850934, 78279, 89182, Antique, Art, Art And Craft, Art Product, British Culture, Cartography, Chart, City, Clyde River, Design, Diagram, Direction, Dumbarton, England, English Culture, Engraved Image, Engraving, Etching, Famous Place, Glasgow, Graph, Highlands Region, History, Illustration, Image Created 1840 1849, Image Created 19th Century, Leicestershire, Lincolnshire, Map, Midlands England, Northamptonshire, Old, Panoramic, Plan, Print, Residential District, River, Road, Scotland, Scottish Highlands, Stream, Stream Flowing Water, Street, Thoroughfare, Tourism, Town, Travel, Uk, Vertical, Victorian Style, Village
St. Brandans Celebration of the Holy Mass Engraving, Circa 1550
Beautifully Illustrated Antique Engraved Victorian Illustration of St. Brandans Celebration of the Holy Mass on the Back of a Whale Engraving, Circa 1550. Source: Kristofer Columbus, Lefnad Och Resor (Christopher Columbus, Life and Voyages), Published in 1893. Original edition from my own archives. Copyright has expired on this artwork. Digitally restored.