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This is the final report about the Eratosthenes Project, a Collaborative project within the Astronomy On-Line Programme.
For earlier reports, see also the article in the Astronomy On-Line Newspaper, a Provisional report of November 16, 1996, and the Provisional report of November 17, 1996.
The project invited the participants to measure the circumference of the Earth, using the method that the ancient Greek astronomer Eratosthenes first introduced around 200 BC.
From November 7th to November 15th, the project Eratosthenes started in collaboration between Greek, Danish, Italian, Czech, Finland and Swedish groups of Astronomy On-Line.
Numerous groups have contributed with exciting measurements. In all, 6 groups from Denmark, 21 from Greece, 1 from Italy, 1 from the Czech Republic, 2 from Sweden and 1 from Finland participated.
Groups in all of these countries have measured the sunlight-shadows of a 1-metre ruler at the instant the Sun passed the local meridian.
The results we have from the different groups are given below:
| Date | Observations between | Earth circumference |
| 7/11/1996 | Greece - Denmark 1st Agias Paraskeuis (GR) - Rosborg (Vejle,DK) |
42.000km |
| 8/11/1996 | Denmark - Greece Toerring Gymnasium (DK) - Ag. Anargiron (GR) |
43.000 km |
| 9/11/1996 | Czech Rep. - Denmark OLH Veseli nad Moravou (CZ) - Southeast Lollandia Stargazers (DK) |
44.000 km |
| 13/11/1996 | Greece - Denmark Supernova (Ioannina, GR) - Soroe Akademi (DK) |
44.500 km | Denmark - Greece Soroe Akademi (DK) - Ziridis Schools, Doukas Schools, 1st Ag. Paraskeuis 19th Peristeriou, 2nd of Holargos (GR) |
43.000 km |
| 14/11/1996 | Denmark - Italy Rosborg (DK) - Kallipolis1 (Sicily, IT) |
39.000 km |
| Greece - Denmark Bjerringbro (DK) - Arsakeio (GR) |
39.500 km | |
| Sweden - Greece Froelundagymnasiet (S) - Arsakeio (GR) |
41.000 km |
The average of the results is 41.500 km and this is less than 5 percent from the official value 40.074 km. This extremely good coincidence is of course merely a question of very good luck - but we still estimate the real accuracy to be within 10 percent. In the calculation we have used the measured values and not those corrected for the atmospheric refraction.
Please direct further enquiries about these results to Dr. Metaxa (e-mail: mmetaxa@athena.compulink.gr).
Below are the results from the schools with the appropriate details about the individual measurements.
Danish Schools
Sonderborg Amtsgymnasium Sonderborg Astronomy Class : Nov 10 : 313 cm +-7 cm (scaled up from a minor gnomon). ------------------------------------------------------------------------- School: Rosborg Amtsgymnasium og HF-kursus, Vejle Place: Vejle Location: 55dg, 43'N, 9dg,31'E Group: Rosborg Amtsgymnasium-1.a,dk Measurements: 8/11 1996: Length of ruler: 100 cm Length of shadow: 311 cm 14/11 1996 Length of ruler: 100 cm Length of shadow: 346 cm ------------------------------------------------------------------------ School: Soroe Akademi. Time: 13/11/96 Length: 11 dg, 33' E Latitude: 55 dg, 26' N Length of ruler: 100 cm Length of shadow: 311 cm Length of shadow: 312cm ---------------------------------------------------------------------------- Toerring Amtsgymnasium Class: 2x and Steen Petersen Besides that the length of shadow was 3,10 m at 1200 nov. 8th our coordinates are: 55 degrees 52' north, 9 degrees 31' east ---------------------------------------------------------------------------- Nysted Youth School Astronomy Team. The longitude of the church in Nysted is stated to be 11 deg 44 min Friday, 08.11, 12.00 MET: Length of shadow =3D 288 cm. Saturday, 09.11, 12.15 MET Length of shadow =3D 297 cm. (cloudy sky until 12.15) Sunday, 10.11, 12.00 MET Length of shadow =3D 298 cm. (beautiful weather !) Wednesday, 13.11, 12.00 MET Length of shadow =3D 298 cm. (cloudy sky, but fair observing conditions) Southeast Lollandia Stargazers --------------------------------------------------------------------------- School: Bjerringbro Gymnasium Group: Astronomyclass Location: 56dg 23'N, 9 dg 39' E Measurements: 14/11 - 1996 Length of ruler: 100cm Length of shadow: 371.5 cmGreek Schools
Arsakeio high school: Groups "red giants" and "observatory" Town :Athens-Ekali Country :Greece longitude:23deg 51.8min latitude:38deg 2.9min date: 7/11/1996 shadow:142+/-1 cm time:12.00 11/11/1996 147+/-1 cm 12.08 13/11/1996 149+/-1 cm 12.09 14/11/1996 150 +/-1 cm 12.09 --------------------------------------------------------------------------- Doukas Schools Groups: Thalis, Eydimos, Aristinicos, Aristarchos Monday 11 - Time of measurement 12:08 Local Time, Length of the Shadow: 145cm Tuesday 12 -Time: 12:08 Length of the Shadow : 1,45 +(-) 0,02 m Wednesday 13- Time: 12:09 Length of the Shadow : 1,49 +(-) 0,02 m Thursday 14 -Time 12:09 Length of the Shadow : 1.5 +(-) 0,02 m --------------------------------------------------------------------------- 1st Gymnasium School of Ag.Paraskeui Groups :Aristarchus,Ptolemy,Hipparhus,Pythagoras Long 23deg 48min 50sec N Lat 38deg 00min 25sec E DATE | TIME | MEASUREMENT(shadow of an 1m ruler) |WEATHER -------------------------------------------------------------------------- 7/11/1996 | 12.00 | 144cm |greek! 11/11/1996 | 12.08 | 147cm |greek! 12/11/1996 | 12.08 | 149.5cm |fair to bad 13/11/1996 | 12.09 | 150.5cm |greek! 14/11/1996 | 12.09 | 153cm (estimation) |bad 15/11/1966 | 13.00 | 163.5cm |greek! --------------------------------------------------------------------------- Peiramatiko Lykeio Ag.Anargiron Group Eratosthenis DATE TIME LENGTH OF SHADOW 7-11-1996 13:00 1420 mm 8-11-1996 13:00 1474 mm 11-11-1996 12:08 1452 mm 12-11-1996 12:08 1472 mm 13-11-1996 12:09 1463 mm 14-11-1996 12:09 1477 mm --------------------------------------------------------------------------- 19 Gymn.of Peristeri Orion Group Place: Athenes, Greece Lat: 38.01.00N Long: 23.44.00 E measuring: 11 November, time 12.08 Greece time Length of ruler: 100,0 cm Length of shadow: 147cm Time of measuring: 12 November, time 12.08 Greece time Length of ruler: 100,0 cm Length of shadow: 147 cm +- 0.5 cm --------------------------------------------------------------------------- 2nd Lyceum of Holargos Groups: Amphitrite, Ariadny, Voyager B.S.V.A, Iniochos, Aquarius 7/11/96:length of the shadow 140 cm at local noon 11/11/96:length of the shadow 154 cm at local noon 12/11/96:length of the shadow 152 cm at local noon 13/11/96:length of the shadow 154 cm at local noon --------------------------------------------------------------------------- Eniaio Polikladiko Likeio of Ioannina Group: Supernova - Ioannina Place: Ioannina, Greece Long : 20.51 dg Lat : 39.40 dg DATE | TIME | MEASUREMENT (Shadow of 1m ruler) --------------------------------------------------------------- 12-11-96 | 12:18 | 158 cm 13-11-96 | 12:19 | 159 cm 14/11/96 | 12.19 | 160 cm 15/11/96 | 12.19 | 161 cm --------------------------------------------------------------------------- Ziridis Schools=20 Group: ziroid.1 Date Time Shadow length 11/11/96 12.08 158 +/- 2 cm 12/11/96 12.08 162 +/- 5 cm 13/11/96 12.08 156,5 cm +/- 3 cm 14/11/96 12.12 165 cm +/- 5 cm Longtitude/Latitude 38 degrees parallel 23-24 degrees meridien --------------------------------------------------------------------------- Hellenic College of Thessaloniki DATE TIME MEASUREMENT 12/11/96 12:08 162 cm 13/11/96 12:09 165 cm 14/11/96 12:32 169 cmCzech School
Observational Report Name of Group: OLH Veseli nad Moravou Town: Veseli nad Moravou Country: Czech Republic Long.: 17 22 17 E Lat.: 48 57 16 N Date: 1996-11-09. 12:00:00 CET Distance to Base of Ruler: 2,271 m (from 3 measurements) Weather conditions: good (this day only)Italian Schools
School: Liceo Scientifico Leonardo. Group: Kallipolis 1 Place: Giarre (Catania), Sicily, Italy. Location: Lat. 37.44 N , Long. 15.13 E. Time: 11/11/96 , Hour: 12.05 p.m. Length of ruler: 100 cm Length of shadow: 142,0 +/- 0.5 Time: 14/11/96 , Hour: 12.05 p.m. Length of shadow: 145.5 cm +/- 0.5 cm Temperature: 18 C. We calculated the distance Giarre-Vejle (on the same meridian) using these measures: It is about 2000 km.Finnish Schools
Tahtikercho group from Helsinski FinlandSwedish Schools
Spraak Froelundagymnasiet Group Texas Yesterday, Thursday 96 11 14, we measured the length of the shadow of one meter exactly at 12.00 o'clock. And we got 3,745 meters. Our teacher thought it was pretty long. And that is true. It was that long. Our long. is 11,55 and the latitude is 57 39' Group Beda Yesterday (11.56 local time - 11.00 UT, Thu. 14/11 -96) we measured the length of the shadow of a 1 meter long ruler and came up with the result: 4,01 meters. Our location is : Longitud 11 55' Latitud 57 39'
| Contact: | Bernard Pellequer, Geospace, Observatoire d'Aniane |
| Voice: 33 (0)4 67 03 49 49 Fax: 33 (0)4 67 75 28 64 | |
| e-mail: geospace@cnusc.fr |