Gerard Kuiper discovers one of Neptune's moons, Nereid.
2
192 years ago, in 1780:
The first binary star system to be discovered, Xi Ursae Majoris, is found by William Herschel.
3
311 years ago, in 1661:
Christiaan Huygens observes the planet Mercury transit the Sun.
257 years ago, in 1715:
During an eclipse in England, Edmond Halley is the first to report the phenomenon later known as Baily's Beads.
4
5 years ago, in 1967:
NASA's Lunar Orbiter 4 is launched to photograph the Moon.
5
11 years ago, in 1961:
Alan Shepard is the first American to be in a suborbital flight around the Earth (Mercury/Freedom 7).
5 years ago, in 1967:
Ariel 3, the first satellite designed and constructed in the United Kingdom, is launched to measure properties of the thermosphere and measure large-scale galactic radio frequency noise.
6
219 years ago, in 1753:
Charles Messier makes his first documented observation; the Mercury transit of the Sun.
54 years ago, in 1918:
The 72 inch Plaskett telescope at The Dominion Astrophysical Observatory in Saanich, British Columbia sees first light.
7 years ago, in 1965:
The Lincoln Calibration Sphere 1 (LCS-1), a large aluminium sphere used for radar calibration, launches with the Lincoln Experimental Satellite-2.
7
9 years ago, in 1963:
Telstar 2 is launched.
8
10 years ago, in 1962:
The first Atlas-Centaur rocket is launched, but the Centaur stage ruptures at 53 seconds into the flight and disintegrates, taking the Atlas with it.
5 years ago, in 1967:
Lunar Orbiter 4 becomes the first spacecraft to go into a polar orbit around the Moon.
9
50 years ago, in 1922:
Tthe IAU passes a resolution to formally adopt Annie Jump Cannon's stellar classification system.
7 years ago, in 1965:
Luna 5 is launched to the Moon.
10
26 years ago, in 1946:
A White Sands modified V-2 rocket reaches 69 miles (111 kms).
7 years ago, in 1965:
Last contact is made with Explorer 18.
11
191 years ago, in 1781:
The Sombrero Galaxy (M104) is discovered by Pierre Méchain.
12
42 years ago, in 1930:
The first planetarium in the United States, Adler Planetarium in Chicago, is opened to the public.
7 years ago, in 1965:
Luna 5 crashes into the Moon, instead of a soft landing as planned.
5 years ago, in 1967:
The Soviet Vostok-2 carrier rocket makes its final flight.
13
239 years ago, in 1733:
Birger Wassenius of Sweden, observing an eclipse near Göteborg, is the first to report prominences visible to the unaided eye; he incorrectly attributes them to the Moon.
111 years ago, in 1861:
John Tebbutt of Australia discovers the Great Comet of 1861 (C/1861 J1).
12 years ago, in 1960:
The original Echo 1, a metalized balloon passive-communications satellite, is launched, but the rocket explodes after lift-off.
This year:
Discovered by astronomer Charles Kowal, SN 1972E becomes the prototype for understanding type Ia supernova.
14
8 years ago, in 1964:
Communications fail for the Venus-bound Zond 1 spacecraft.
15
15 years ago, in 1957:
The first launch of a Soviet R-7 Semyorka leads to an unintended crash 400 km (250 mi) from the launch site.
14 years ago, in 1958:
Sputnik 3 is launched to explore the upper atmosphere and near space.
12 years ago, in 1960:
Korabl-Sputnik 1 (Sputnik 4), the first and unmanned test flight of the Vostok, is launched.
9 years ago, in 1963:
Mercury/Faith 7, the last Mercury mission, orbits the earth 22 times, with astronaut L. Gordon Cooper, Jr.
16
7 years ago, in 1965:
Telstar 2 is turned off.
3 years ago, in 1969:
Venera 5 reaches Venus and sends a probe into the atmosphere; it returns data for 53 minutes.
17
90 years ago, in 1882:
On an expedition in Egypt , Dr. Arthur Schuster sees a comet (Tewfik) near the Sun during a total eclipse.
3 years ago, in 1969:
Venera 6 reaches Venus and sends a probe into the atmosphere; it returns data for 51 minutes.
18
3 years ago, in 1969:
Apollo 10 is launched; the first with the complete spacecraft (LM & CM).
19
11 years ago, in 1961:
Venera 1 is the first craft to fly by Venus, though contact is lost.
1 year ago, in 1971:
The Soviet Mars 2 spacecraft is launched.
20
21
188 years ago, in 1784:
William Herschel discovers NGC 6287, a globular cluster in the constellation Ophiuchus.
3 years ago, in 1969:
Apollo 10 enters lunar orbit, circles the Moon 31 times, tests LM separation.
22
188 years ago, in 1784:
William Herschel discovers NGC 6284, a globular cluster in the constellation Ophiuchus.
26 years ago, in 1946:
A White Sands WAC Corporal reaches the then-defined edge of space, 50 miles (80 kms).
23
14 years ago, in 1958:
Explorer 1 makes its final transmission.
24
429 years ago, in 1543:
Nicolaus Copernicus dies at age 70 in Frauenburg, Royal Prussia, Kingdom of Poland.
137 years ago, in 1835:
John Herschel discovers NGC 6325, a globular cluster in the constellation Ophiuchus.
10 years ago, in 1962:
Mercury/Aurora 7 orbits the earth with astronaut Scott M. Carpenter.
4 years ago, in 1968:
Echo 1A re-enters Earth's atmosphere and burns up.
25
11 years ago, in 1961:
President Kennedy makes his famous "Moon speech".
7 years ago, in 1965:
AS-104 (SA-8), is successfully launched, carrying the fourth 'boilerplate' version of the Apollo spacecraft and the second Pegasus micrometeroid detection satellite.
26
3 years ago, in 1969:
Apollo 10 splashes down in the Pacific Ocean and is retrieved by the USS Princeton.
27
28
13 years ago, in 1959:
Launched aboard a Jupiter ICBM, Able and Baker became the first monkeys to survive spaceflight.
8 years ago, in 1964:
AS-101 (SA-6), is successfully launched, carrying the first 'boilerplate' version of the Apollo spacecraft.
1 year ago, in 1971:
The Soviet Mars 3 spacecraft is launched.
29
53 years ago, in 1919:
Arthur Eddington confirms Einstein's theory of general relativity during a total solar eclipse.
This year:
After only 35 days and 425 orbits after its release, the Apollo 16 Particles and Fields Subsatellite (PFS-2) crashes into the Moon.
30
6 years ago, in 1966:
Surveyor 1 is launched for the Moon.
1 year ago, in 1971:
Mariner 9 is launched to Mars.
31
37 years ago, in 1935:
The David Dunlap Observatory in Richmond Hill, Ontario, housing a 74-inch (1.88 m) reflector telescope (still the largest in Canada), has its official opening .
It's been 3960 days
