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Final Report on the Eratosthenes Project

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:

DateObservations betweenEarth circumference
7/11/1996Greece - Denmark
1st Agias Paraskeuis (GR) - Rosborg (Vejle,DK)
42.000km
8/11/1996 Denmark - Greece
Toerring Gymnasium (DK) - Ag. Anargiron (GR)
43.000 km
9/11/1996Czech Rep. - Denmark
OLH Veseli nad Moravou (CZ) - Southeast Lollandia Stargazers (DK)
44.000 km
13/11/1996Greece - 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
14/11/1996Denmark - 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.

Dr. M. Metaxa (Greece)

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

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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


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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

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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 cm

Greek 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

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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

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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!

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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

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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

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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

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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

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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 cm

Czech 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 Finland

Swedish 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

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