28th August 1789
Saturn’s moon Enceladus is discovered by Sir William Herschel during the first use of his new 1.2 m telescope, then the largest in the world. Enceladus is about 500 km in diameter and orbits Saturn every 32.9 hours, fast enough for its motion to be observed over a single night of observation. Enceladus is the sixth-largest moon of Saturn and orbits keeping one face pointed toward the planet. The moon is named after the giant, Enceladus, of Greek mythology
18th August 1836
Helium is discovered. The first evidence of helium is discovered by French astronomer Jules Janssen when he noticed a yellow line in the Sun's spectrum while studying a total solar eclipse in 1868. Helium is the second most abundant element in the universe and makes up about 0.0005% of the earth's atmosphere. It is a colourless, odourless, tasteless, non-toxic, inert, monatomic gas, the first in the noble gas group in the periodic table. Its boiling point is the lowest among all the elements.
19th August 1960
Russian spacecraft Sputnik 5 launched. On board were two dogs – Strelka (“Little Arrow”) and Belka (“Squirrel”) - 1 rabbit, 40 mice, 2 rats, flies, plants. They all survived the mission and were the first Earth creatures to return to Earth from space alive.The stamp above,was produced on the 50th anniversary of the flight courtesy Wiki Commons.
16th August 1744 Pierre Mechain. French astronomer. Together with Charles Messier he was a major contributor to the early study of deep sky objects and comets. Like Messier he never set out to observe deep-sky objects and was solely interested in cataloguing objects that might be mistaken for comets; Altogether, he discovered around 25 deep-sky objects, eight comets, and co-discovered three comets.
1st August 1905 Helen Sawyer Hogg, pictured above in the 1960s. American astronomer. Noted for pioneering research into globular clusters and variable stars. She was the first female president of several astronomical organizations and a notable woman of science in a time when many universities would not award scientific degrees to women.
19th August 1924 Willard Boyle. Canadian physicist. He was a pioneer in the field of laser technology and co-inventor of the charge-coupled device, a piece of metal about the size of a 5 cent piece that captures and stores light and displays it by turning it into an electrical charge. The device made digital photography possible and revolutionized astronomy and space science. As director of Space Science and Exploratory Studies at Bell Labs he helped select lunar landing sites and provided support for the Apollo space program.