Eratosthenes Festivity is an annual event organized by the the Planetarium Science Center (PSC) on 21 June every year since 2003; the day of Summer Solstice in Alexandria and Aswan. Eratosthenes, the Greek scientist and the third librarian of the Ancient Library of Alexandria, was the first scientist who measure the circumference of the Erath before 2000 years ago in these two cities.
Eratosthenes, at the time Director of the Great Library of Alexandria in Egypt, proposed a purely geometrical method to measure the length of the Earth’s meridian (circle passing through the poles). He started by using the observation of shadows made at two different places, Alexandria and Syene (now Aswan) distanced approximately 800 km apart (distance estimated in relation to the time taken by a caravan of camels to connect the two towns !) at the time of the Summer solstice and at noon local solar time.
Local Partners Governorate
Latitude
Longitude
Circumference (km)
Aswan
24.0889
32.8998
0
Alexandria
31.2001
29.9187
40,075 km
El Minia
28.0889
30.7586
40,671 km
Suhag
26.5591
31.6957
40,360 km
Damietta
31.3626
31.6739
41,500 km
El Behira
30.8481
30.3436
45,000 km
Mansoura
31.0832
31.4913
40,000 km
Aswan
24.0908
32.8994
0
Luxor
25.6872
32.6396
43,020 km
Qena
26.0513
32.2200
40,550 km
El Monufia
52.374
4.8896
39,670 km
Guarne Colombia
Brazรณpolis Brazil Piranguinho Brazil Rio de Janeiro Brazil
Alta Gracia Chivilcoy
Argentina Argentina
Băicoi Romania Busteni Romania MargineniRomania Oradea Romania Pogana Romania
Cernay France Lafrançaise France
Medvode Slovenia
Úbeda Spain Mohammedia Tunisia
Aigio Greece Ilion Greece PetroupoliGreece Piraeus Greece Jagadhri India Yamunanagar India
Aigio Greece 1st High School of Aigio
Gnomon Shadow Angle (°) height [cm ] length [cm ] 18/06/2018 30 7.9 14.8 Date
Alta Gracia Argentina Fundacion Caminos de Anisacate Gnomon Shadow Angle (°) height [cm ] length [cm ] 18/06/2018 38 -53.5 -54.6 21/06/2018 40 -56.5 -54.7 22/06/2018 40 -56.6 -54.8 Date
Băicoi Romania Liceul Tehnologic Constantin Cantacuzino
Gnomon Shadow Angle (°) height [cm ] length [cm ] 22/06/2018 100 39 21.3 Date
Brazópolis Brazil Pico dos Dias Observatory Gnomon Shadow Angle (°) height [cm ] length [cm ] 20/06/2018 49 -51.3 -46.3 Date
Busteni Romania Scoala Gimnaziala Sanatoriala
Date 19/06/2018 20/06/2018 21/06/2018 22/06/2018
Gnomon Shadow Angle (°) height [cm ] length [cm ] 34.7 14 22 27.2 11 22 20 8.1 22 22.3 9 22
Cernay France Collège René Cassin
Gnomon Shadow Angle (°) height [cm ] length [cm ] 21/06/2018 368.5 167 24.4 Date
Chivilcoy Argentina Parque Cielos del Sur
Date 18/06/2018 19/06/2018 20/06/2018 21/06/2018
Gnomon Shadow Angle (°) height [cm ] length [cm ] 80 -130 -58.4 80 -130 -58.4 80 -130 -58.4 80 -130 -58.4
Guarne Colombia Grupo Astrofánaticos
Date 18/06/2018 19/06/2018 20/06/2018 21/06/2018 22/06/2018
Gnomon Shadow Angle (°) height [cm ] length [cm ] 31 -9.6 -17.2 31 -9.7 -17.4 31 -9.3 -16.7 31 -9.3 -16.7 31 -9.5 -17
Ilion Greece 11th Junior High School of Ilion
Gnomon Shadow Angle (°) height [cm ] length [cm ] 21/06/2018 30.4 7.9 14.6 Date
Jagadhri India S.V.N.Public School Jagadhri
Gnomon Shadow Angle (°) height [cm ] length [cm ] 20/06/2018 58.2 22.6 21.2 Date
Lafrançaise France Collège Antonin Perbosc
Gnomon Shadow Angle (°) height [cm ] length [cm ] 18/06/2018 100 37.8 20.7 21/06/2018 100 37.8 20.7 22/06/2018 100 37.8 20.7 Date
Margineni Romania Secondary School Gh. Popescu
Gnomon Shadow Angle (°) height [cm ] length [cm ] 20/06/2018 100 39.4 21.5 21/06/2018 100 39.4 21.5 22/06/2018 100 39.4 21.5 Date
Medvode Slovenia Osnovna ĹĄola Preska
Gnomon Shadow Angle (°) height [cm ] length [cm ] 19/06/2018 20.3 7.9 21.3
Date
Mohammedia Tunisia Osnovna ĹĄola Preska
Gnomon Shadow Angle (°) height [cm ] length [cm ] 21/06/2018 90 20 12.5 Date
Oradea Romania Colegiul Tehnic Traian Vuia
Gnomon Shadow Angle (°) height [cm ] length [cm ] 21/06/2018 100 43.8 23.7 22/06/2018 100 43.8 23.7 Date
Petroupoli Greece 4th Junior High School of Petroupolis
Gnomon Shadow Angle (°) height [cm ] length [cm ] 18/06/2018 52.3 13.6 14.6 Date
Piraeus Greece 2nd Junior High School of Korydallos
Gnomon Shadow Angle (°) height [cm ] length [cm ] 20/06/2018 100 24 13.5 Date
Piranguinho Brazil Universidade Federal de Itajubå Gnomon Shadow Angle (°) height [cm ] length [cm ] 19/06/2018 70 -71.9 -45.8 21/06/2018 70 -71.7 -45.7 22/06/2018 70 -71.7 -45.7 Date
Pogana Romania Scoala Gimnaziala Nr.1 Pogana
Gnomon Shadow Angle (°) height [cm ] length [cm ] 19/06/2018 60 25.1 22.7 21/06/2018 80.1 33.8 22.9 Date
Rio de Janeiro Brazil Centro Educacional Nosso Mundo
Gnomon Shadow Angle (°) height [cm ] length [cm ] 20/06/2018 100 -98 -44.4 21/06/2018 100 -98 -44.4 Date
Ăšbeda Spain Colegio Salesiano Santo Domingo Savio
Gnomon Shadow Angle (°) height [cm ] length [cm ] 22/06/2018 130.4 33.7 14.5 Date
Yamunanagar India C V Raman Science Club
Gnomon Shadow Angle (°) height [cm ] length [cm ] 21/06/2018 28 3.3 6.7 Date