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June 17, 2019 - The Brewer who Discovered Triton

The Brewer who Discovered Triton  William Lassell, born 220 years ago this week, made a fortune brewing beer in Liverpool during the mid-19th century. With his sizable profits, Lassell financed his real passion, astronomy. He built a 61 cm (24 in) reflecting telescope, which at the time was the most powerful telescope in England. In September 1846, he read about the discovery of the planet Neptune, and less than a month later he turned his telescope toward Neptune and discovered its largest Moon, Triton, which is slightly smaller than Earth’s Moon. It has one of the coldest surfaces known anywhere in the solar system, and it is one of only a few worlds that possess a nitrogen-rich atmosphere. This composite view, based on Voyager 2 data, shows Neptune as seen from the surface of Triton.

Image credit: NASA / JPL

Weekly Calendar

June 17 - 23, 2019

Holidays - Sky Events - Space History


Moon phase Monday 17

Full Moon 4:31 AM ET
Venus 5° north of Aldebaran

1985: STS-51G Discovery launched

Moon phase Tuesday 18

Mercury 0.2° north of Mars

1799: William Lassell born
1983: STS-7 Challenger launched; Sally Ride becomes first American woman in space
2009: Lunar Reconnaissance Orbiter (LRO) and Lunar Crater Observation and Sensing Satellite (LCROSS) launched

Moon phase Wednesday 19

Saturn 0.4° north of Moon
Pluto 0.07° north of Moon

1999: QuikSCAT launched

Moon phase Thursday 20

1985: NASA announces cola wars will take place on shuttle mission STS-51F
1996: STS-78 Columbia launched

Moon phase Friday 21

Mercury 6° south of Pollux
Solstice 11:54 AM ET

1993: STS-57 Endeavour launched
2004: SpaceShipOne launched, first privately-funded human space flight

Moon phase Saturday 22

Neptune appears stationary

1675: Royal Greenwich Observatory founded
1973: 28-day Skylab 2 mission ends
2000: NASA announces evidence of present-day liquid water on Mars

Moon phase Sunday 23

Mars 6° south of Pollux
Moon at apogee
Mercury at greatest elongation (25° E)

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