A partial solar eclipse occurred on April 13, 1801. The eclipse was visible in Russia, Northern Europe and Greenland.http://en.wikipedia.org/wiki/Solar_eclipse_of_April_13,_1801
Transit of Mars across the Sun's disc, which occurred for the planet Jupiter on April 13, 1886http://adsabs.harvard.edu/abs/1886MNRAS..46..161M
Rongali Bihu celebrates the beginning of the Assamese New Year on April 13http://en.wikipedia.org/wiki/Bohag_Bihu#Rongali_Bihu
Project MKULTRA, or MK-ULTRA, was the code name for a covert CIA human experimentation programhttp://astronomy.activeboard.com/t48704019/project-mkultra/
Missing experimental Corona satellite capsule (Discoverer II) inadvertently landed near Spitzbergen on April 13, 1959http://en.wikipedia.org/wiki/Corona_(satellite)#Popular_culture
The Transit 1B Satellite was launched on April 13, 1960http://en.wikipedia.org/wiki/Transit_%28satellite%29Westar 1 was America's first domestic and commercially launched geostationary communications satellite, launched on April 13, 1974.http://en.wikipedia.org/wiki/Westar_1
Jean-Jacques Favier (Born April 13, 1949) is a French engineer and a former CNES astronauthttp://en.wikipedia.org/wiki/Jean-Jacques_Favier
Werner Voss (13 April 1897 - 23 September 1917) was a World War I German flying ace credited with 48 aerial victories.http://en.wikipedia.org/wiki/Werner_Voss
Robert Alexander Watson-Watt (13 April 1892 - 5 December 1973) is considered by many to be the "inventor of radar". http://en.wikipedia.org/wiki/Robert_Watson-Watt
Richard Assmann (13 April 1845 - 28 May 1918) was a German meteorologist and physicianhttp://en.wikipedia.org/wiki/Richard_AssmannBruno Benedetto Rossi (13 April 1905 - 21 November 1993) was an Italian experimental physicist. http://en.wikipedia.org/wiki/Bruno_Rossi
Arthur Matthew Weld Downing (13 April 1850 - 8 December 1917) was a British astronomer.http://en.wikipedia.org/wiki/Arthur_Matthew_Weld_Downing
Star Trek: "Operation: Annihilate!" was first broadcast on April 13, 1967.
NGC 2835 was discovered by Wilhelm Tempel on the 13th April 1884.http://astronomy.activeboard.com/t57289818/ngc-2835/NGC 3365 was discovered by John Herschel on the 13th April 1828.http://astronomy.activeboard.com/t57289803/ngc-3365/NGC 3539 was discovered by John Herschel on the 13th April 1831.http://astronomy.activeboard.com/t57289795/ngc-3539/
NGC 3567 was discovered by William Herschel on the 13th April 1784.http://astronomy.activeboard.com/t59639906/ngc-3567/NGC 3678 was discovered by John Herschel on the 13th April 1831.http://astronomy.activeboard.com/t57289781/ngc-3678/NGC 4001 was discovered by George Johnstone Stoney on the 13th April 1852.http://astronomy.activeboard.com/t57289773/ngc-4001/NGC 4180 was discovered by William Herschel on the 13th April 1784.http://astronomy.activeboard.com/t57289766/ngc-4180/NGC 4197 was discovered by William Herschel on the 13th April 1784.http://astronomy.activeboard.com/t57289755/ngc-4197/NGC 4260 was discovered by William Herschel on the 13th April 1784.http://astronomy.activeboard.com/t57289744/ngc-4260/NGC 4261 was discovered by William Herschel on the 13th April 1784.http://astronomy.activeboard.com/t57289733/ngc-4261/NGC 4264 was discovered by William Herschel on the 13th April 1784.http://astronomy.activeboard.com/t57289727/ngc-4264/NGC 4296 was discovered by William Herschel on the 13th April 1784.http://astronomy.activeboard.com/t57289723/ngc-4296/NGC 4297 was discovered by William Herschel on the 13th April 1784.http://astronomy.activeboard.com/t57289718/ngc-4297/
NGC 4370 was discovered by William Herschel on the 13th April 1784.http://astronomy.activeboard.com/t60197957/ngc-4370/NGC 4400 was discovered by George Johnstone Stoney on the 13th April 1850.http://astronomy.activeboard.com/t57289702/ngc-4400/NGC 4532 was discovered by William Herschel on the 13th April 1784.http://astronomy.activeboard.com/t57289690/ngc-4532/NGC 4526 was discovered by William Herschel on the 13th April 1784.http://astronomy.activeboard.com/t52467337/ngc-4526/NGC 4563 was discovered by Heinrich d'Arrest on the 13th April 1864.http://astronomy.activeboard.com/t57289665/ngc-4563/NGC 4570 was discovered by William Herschel on the 13th April 1784.http://astronomy.activeboard.com/t57289658/ngc-4570/NGC 4588 was discovered by William Herschel on the 13th April 1784.http://astronomy.activeboard.com/t57289652/ngc-4588/NGC 4623 was discovered by William Herschel on the 13th April 1784.http://astronomy.activeboard.com/t57289645/ngc-4623/NGC 4853 was discovered byJohn Herschel on the 13th April 1831.http://astronomy.activeboard.com/t57289637/ngc-4853/NGC 4864 was discovered by John Herschel on the 13th April 1831.http://astronomy.activeboard.com/t57289630/ngc-4864/NGC 5210 was discovered by William Herschel on the 13th April 1784.http://astronomy.activeboard.com/t57289623/ngc-5210/NGC 5235 was discovered by William Herschel on the 13th April 1784.http://astronomy.activeboard.com/t57289619/ngc-5235/NGC 5239 was discovered by William Herschel on the 13th April 1784.http://astronomy.activeboard.com/t57289614/ngc-5239/NGC 5682 was discovered by George Johnstone Stoney on the 13th April 1850.http://astronomy.activeboard.com/t57289606/ngc-5682/NGC 5683 was discovered by George Johnstone Stoney on the 13th April 1850.http://astronomy.activeboard.com/t57289599/ngc-5683/NGC 5693 was discovered by George Johnstone Stoney on the 13th April 1850.http://astronomy.activeboard.com/t57289593/ngc-5693/NGC 5906 was discovered by George Johnstone Stoney on the 13th April 1850.http://astronomy.activeboard.com/t57289583/ngc-5906/NGC 5910 was discovered by William Herschel on the 13th April 1785.http://astronomy.activeboard.com/t57289578/ngc-5910/NGC 6106 was discovered by William Herschel on the 13th April 1784.http://astronomy.activeboard.com/t57289574/ngc-6106/Messier 4 was discovered by Philippe Loys de Chéseaux in 1746. http://astronomy.activeboard.com/t47335167/messier-4/
MeteoritesThe Mulletiwu (L) meteorite fell in Northern, Sri Lanka, on the 13th April, 1795.http://astronomy.activeboard.com/t48703912/mulletiwu-meteorite/The Lesves (L6) meteorite fell in Namur, Belgium, on the 13th April, 1896.http://astronomy.activeboard.com/t48703915/lesves-meteorite/The Sakauchi (L6) meteorite fell in Chubu, Japan, on the 13th April, 1913.http://astronomy.activeboard.com/t48703929/sakauchi-meteorite/The Tomita (L) meteorite fell in Chugoku, Japan, on the 13th April, 1916.http://astronomy.activeboard.com/t48703918/tomita-meteorite/The Mason Gully (H5 chondrite) meteorite fell in Western Australia, on the 13th April, 2010.http://astronomy.activeboard.com/t57290025/mason-gully-meteorite/