Histoire(de(l`Astronomie( ( IV(–(Les(XIXe(et(XXe(siècles

!"#$%"&'()'(*+#$&%,%-"'(
./&(01%-/#(2")'-/,,((
34#'&5/$%"&'()'(6/&"#(789:;+<(
(
;=(>(8'#(?;?'('$(??'(#"@A*'#(
!
!
!
!
!
(
BCBDEBFGF(
H +.&@#(*I.%JK'()'#(."%,,"'&#()'#(?=;'('$(?=;;'(#"@A*'#(>(0LA1%(
M&/1IN(O/*"*I'(%K(P'.*'&N(('$(*/(&K.$K&'(",A/&,I'(./&(Q'R$%,N(*'(
?;?'(#"@A*'('#$(-/&JKI(./&(K,(",$I&S$(",$',#'(.%K&(*%4#'&5/$"%,(
)K(A"'*N(I.'&%,,I(./&(*'(#%KA"(,%K5'/K()'(*/(-I$I%&%*%T"'('$(*'#(
.&%T&@#()'(*/(-'#K&'()K($'-.#U(VK(.%",$()'(5K'($1I%&"JK'N(A'#$(
K,'(.I&"%)'()'(*/$',A'N(/5/,$(*'#(,%K5'**'#(&I5%*K$"%,#()K(??'(
#"@A*'(7$1I%&"'()'#(JK/,$/('$(&'*/$"5"$I<(-/"#(*'#(.&%T&@#()'#(/K$&'#(
#A"',A'#('$($'A1,"JK'#(7,/$K&/*"#-'N(I5%*K$"%,N(-I)'A",'N(
$I*IT&/.1"'N(.1%$%T&/.1"'<('$(*'#(%4#'&5/$"%,#(#'(-K*$".*"',$U(9**'#(
A%,A'&,',$()'(,%K5'**'#(.*/,@$'#(7W&/,K#(',(BXCBN(Q'.$K,'(',(
BCDY<N(*/(,/$K&'(T/Z'K#'()'(*/(#K&[/A'()K(#%*'"*('$()'(A'&$/",'#(
I$%"*'#N(*'#(-I$I%&"$'#(7)%,$(*/(A1K$'()'(8/"T*'N(',(BC\]N(-%$"5/(K,(
5I&"$/4*'(5%L/T'(#A"',$"^JK'<N(*'#(A%-@$'#N(*/(=%"'(*/A$I'(7JK'(*%,(
A%--',_/"$(`(/..'*'&(*/(T/*/a"'<N(*'#(,I4K*'K#'#N('$AU(b'(.&%T&@#(
)'#(A%,,/"##/,A'#(#/AA%-./T,'()'(*/(-"#'(',(.*/A'(
)",#$"$K$"%,#(,%K5'**'#(>(`(A%--',A'&(./&(*'(MK&'/K()'#(
*%,T"$K)'#N(A&II(',(BXFcN(/KJK'*([K$(4"',$d$(&/$$/A1I(
*34#'&5/$%"&'()'(6/&"#U(
Première!détermination!de!la!vitesse!de!la!lumière!!
73*'(ef-'&N(BYDDEBXB\<!
6"A/&)(5"#"$'(W&/,"',4%&T(.%K&(-'#K&'&(/5'A(
.&IA"#"%,(*/(*%,T"$K)'()'#(%4#'&5/$"%,#()'(
0LA1%(M&/1IU(;*(L(&',A%,$&'(ef-'&(
7BYDDEBXB\<(JK’"*(",5"$'(`($&/5/"**'&(`(
*’34#'&5/$%"&'()'(6/&"#(#%K#(*/()"&'A$"%,()'(
b/##","(.%K&(I$/4*"&(*'#($/4*'#()'#(
.1I,%-@,'#(-K$K'*#()'#(#/$'**"$'#()'(
gK."$'&(7"--'&#"%,(bN(I-'&#"%,(V<U((
(
;*([K$(*'(.&'-"'&(`()I$'&-",'&(*/(5"$'##'()'(*/(
*K-"@&'(',(%4#'&5/,$(*'#(IA*".#'#()'#(
#/$'**"$'#(./&(*’%-4&'()'(gK."$'&(`()'#(
)"#$/,A'#(0'&&'EgK."$'&()"hI&',$'#U(8'(&'$/&)(
#K&(*'#(I.1I-I&")'#(/KT-',$'(/5'A(*/(
)"#$/,A'U((
8/()"hI&',A'('#$()'(BY(-",(GY(#(',$&'()'Ka(
#I&"'#()'(-'#K&'#(7PN(8<(%K(7iNO<U3,()I)K"$(
/",#"(*/()K&I'(7FCY(#<(-"#'(./&(*/(*K-"@&'(
.%K&(./&A%K&"&(K,'()"#$/,A'(A%&&'#.%,)/,$(`(
*’K,"$I(/#$&%,%-"JK'U((
C!
g/-'#(M&/)*'L(7BYF]EBXYG<(
(
BXGC(j()IA%K5&'(*/4'&&/$"%,(/,,K'**'U(8'()'-"ET&/,)(/a'()'(*'**".#'N(
./&/**@*'(`(*IA*".$"JK'N(-'#K&'(G\NDCk(.%K&($%K$'#(*'#(I$%"*'#(
%4#'&5I'#U(M&/)*'L()I-%,$&'(/",#"(*/(A%,l'A$K&'()'(ef-'&(#K&(*/(
*K-"@&'N('$(/..%&$'(*/(.&'-"@&'(.&'K5'(('a.I&"-',$/*'()K(-%K5'-',$(
%&4"$/*()'(*/(0'&&'(7+#$&%,%-'(e%L/*(',(BXDGN(#KAA@)'(`(!/**'L<(
i&"')&"A1(2"*1'*-(M'##'*(7BXCDEBCDY<(
(
VIA%K5&'(*/(./&/**/a'(#$'**/"&'U(9,(BC]C(j(-'#K&'((
*/(./&/**/a'()'(*I$%"*'(YB(bLT,"(IT/*'(`(\UGFCU(
B(./&#'A(m(]NGY(/,,I'#E*K-"@&'(m(./&/**/a'(B(U(
8K,"5'&#(#$'**/"&'(`(]()"-',#"%,#(j(
8/(./&/**/a'(#$'**/"&'(7BC]C<(
!"#$%&'!($)*+!!!!!!
!,-../!0!1$*234'5!-6789!
!
!:)+)';*!<34'*4=!
,-.660>?==4!2:@3&A5!-67.9!
(*/(*K-"@&'('#$(K,'(%,)'(A/&('**'(
#'K*'(.'&-'$()'a.*"JK'&(*'#(
.1I,%-@,'#()'()"h&/A$"%,('$(
)'(.%*/&"#/$"%,U(
(!L.%$1@#'()K(n(5',$()I$1'&(o(
;(>(8/(*K-"@&'N()'(i&/K,1%['&(`(6*/,Ap(
g%#'.1(5%,(i&/K,1%['&(7BXCX(E(BCGY<(
i&/,_%"#(+&/T%(7BXCY(E(6/&"#N(BCc]<(
8I%,(i%KA/K*$(76/&"#N(BCBF(E(BCYC<(
!"..%*L$'(i"Z'/K(7BCBB(E(BCXX<(
g/-'#(b*'&p(q/aR'**(7BC]B(E(BCXF<(
q/a(6*/,Ap(7BCcC(E(BFDX<((
(

g%#'.1(5%,(i&/K,1%['&(7BXCXEBCGY<(
3&.1'*",(`(BB(/,#N("*($&/5/"**'(
A%--'(/..&',$"(.%K&(K,(
[/4&"A/,$()'(5'&&'U(+(BD(/,#("*(
#K&5"$(/(K,('h%,)&'-',$()'(
*/$'*"'&('$('#$(.&%$ITI()K(
6&",A'(I*'A$'K&()'(M/5"@&'(
q/a"-"*"',(g%#'.1U((
(
H(BCBD(j(",5',$'(*'(
#.'A$&%#A%.'('$()IA%K5&'(cXD(
&/"'#(#%-4&'#()/,#(*'(#.'A$&'(
#%*/"&'(
(
H(VIA%K5&'(JK'(*/(.*K./&$()'#(
#.'A$&'#()I$%"*'#()'(.&'-"@&'(
T&/,)'K&()"h@&',$()'(A'*K"()K(
#%*'"*(
:.'A$&%-I$&"'('$(.1%$%-I$&"'(
8/(,/$K&'()'(*/(*K-"@&'(
(
+K(?;?'(#"@A*'(j(()'Ka($1I%&"'#(j(V'#A/&$'#(7%,)K*/$%"&'<((
Q'R$%,(7BYD]EBXGX<(.',#/"$(JK'**'(I$/"$(A%,#$"$KI'()'(A%&.K#AK*'#(I-"#(./&(*/(
#%K&A'(*K-",'K#'(7$1I%&"'(A%&.K#AK*/"&'<U((
(
6%K&(i&'#,'*(7BXCCEBCGX<(.K"#(i&/,_%"#(+&/T%N(*/(*K-"@&'('#$(K,'(%,)'(A/&('**'(#'K*'(
.'&-'$()'a.*"JK'&(*'#(.1I,%-@,'#()'()"h&/A$"%,('$()'(.%*/&"#/$"%,U((
(
8'#()'Ka($1I%&"'#(&',)/"',$(./&(/"**'K&#(A%-.$'()'([/_%,()"hI&',$'()'#(*%"#()'(*/(
&I[&/A$"%,N(A'#$E`E)"&'()K(.1I,%-@,'(",)K"$(./&(*'(./##/T'()'(*/(*K-"@&'()K,(
-"*"'K($&/,#./&',$(`(K,(/K$&'(j((
E !"#$%&'()%&#*+,-%(&(I$/"$(*/($1I%&"'()'(* I-"##"%,(7A%&.K#AK*/"&'<U(b'**'EA"(#K..%#/"$(
JK'(*/(AI*I&"$I()'(*/(*K-"@&'(/KT-',$'(/5'A(*/()',#"$I()K(-"*"'KN(((((((((()%,A('**'(
#'&/"$(.*K#(I*'5I'()/,#(* /"&(JK'()/,#(*'(5")'U(#
!"#.&/-01&#*+,-%(&(I$/"$(*/($1I%&"'(%,)K*/$%"&'(#'*%,(*/JK'**'(*/(5"$'##'()'(*/(
*K-"@&'(I$/"$(",5'&#'-',$(.&%.%&$"%,,'**'(`(* ",)"A'()'(&I[&/A$"%,(7,(#K.I&"'K&(%K(
IT/*(`(B<N()%,A('**'(#'&/"$(.*K#([/"4*'()/,#(* '/KU(
6%K&($&/,A1'&N("*([/**/"$()%,A(A%-./&'&('a.I&"-',$/*'-',$(*/(5"$'##'()'(*/(*K-"@&'(
)/,#(*r'/K('$()/,#(*r/"&N(A'(JK+&/T%(',$&'.&"$(',(BCD](/5/,$()'()'5%"&(L(&',%,A'&(
.%K&()'#(&/"#%,#()'(#/,$IU(i%KA/K*$('$(i"Z'/K(.&"&',$(#/(&'*@5'U((
(
8'(GX(/5&"*(BCc\N(i%KA/K*$(76/&"#N(BCBF(E(BCYC<(&IK##"$(*'(.&'-"'&(*'a.I&"',A'N(&K",/,$(
)I^,"$"5'-',$(A'(JK"*(/..'*/"$(n(A'$$'(./K5&'($1I%&"'()'(*I-"##"%,(o(s(i"Z'/K(L(
./&5",$(#"a(#'-/",'#(.*K#($/&)U((
8I%,(i%KA/K*$((
76/&"#N(BCBF(E(BCYC<(
8'(.',)K*'()'(i%KA/K*$(
6&'-"@&'(.&'K5'(-IA/,"JK'(
)K(-%K5'-',$()"K&,'(

8'(.',)K*'()'(i%KA/K*$(
6&'-"@&'(.&'K5'(-IA/,"JK'(
)K(-%K5'-',$()"K&,'(
g/-'#(b*'&p(q/aR'**(79)"-4K&TN(BC]B(E(BCXF<(
Q/$K&'(I*'A$&%-/T,I$"JK'()'(*/(.&%./T/$"%,(*K-",'K#'(
tK/,$"^A/$"%,()K(&/L%,,'-',$()'(A%&.#(,%"&(j(((
q/a(6*/,Ap(7BCcCEBFDX<(.K"#(9",#$'",(7BCXFEBFcc<#
q/a(6*/,Ap(`(P"'*('$('h'A$K'()'#(I$K)'#()'(
-/$1I-/$"JK'#(`(qK,"A1U(;*($&/5/"**'(',#K"$'(#K&(*'(
&/L%,,'-',$($1'&-"JK'N(JK"N(`(*rI.%JK'('#$(-/*(
-%)I*"#I(./&(*'#($1I%&"'#(A*/##"JK'#U(;*(&IA%,A"*"'(*'(
&/L%,,'-',$($1'&-"JK'(A%,$",K(7A%&.#(,%"&<(/5'A(
*/($1'&-%)L,/-"JK'(#$/$"#$"JK'(',([/"#/,$(
",$'&5',"&(K,'(JK/,$"^A/$"%,()'#(#%K&A'#()'(
*rI,'&T"'N(`(*r%&"T",'()'(*/(.1L#"JK'(JK/,$"JK'()K(
??'(#"@A*'U((
(
9",#$'",(A%-.*@$'&/(*'($&/5/"*()'(6*/,ApN(',(
JK/,$"^/,$(*'(&/L%,,'-',$(I*'A$&%-/T,I$"JK'(*K"E
-S-'(7.1%$%,#<U(q/a(6*/,Ap(&'_%"$(*'(Q%4'*(',(
BFBCU((;*(&'#$'(',(+**'-/T,'(.',)/,$(*/(TK'&&'N(%u(
#/(5"'([/-"*"/*'('#$()&/-/$"JK'j(#%,(I.%K#'(-'K&$(
$&@#(l'K,'N($&%"#()'(#'#(JK/$&'(',[/,$#()IA@)',$(
IT/*'-',$(7*rK,(/K([&%,$('$()'Ka(^**'#(*%&#()'(*'K&#(
/AA%KA1'-',$#<U(W,(^*#("##K()'(#%,(#'A%,)(
-/&"/T'(#'&/([K#"**I(./&(*'#(/**'-/,)#N(/.&@#(K,'(
$',$/$"5'()r/##/##",/$()r!"$*'&U(:/(-/"#%,('#$(
4%-4/&)I'(./&(*'#(/**"I#(',(BFDcU(;*(#'&/(&'AK'"**"(
./&(K,'(-"##"%,(/-I&"A/",'U(
!'&$Z.&K,TEeK##'*((
7BF\c('$(BFB]<(
;;(>(6&%T&@#()'(*/#$&%,%-"'(.1L#"JK'((
'$(A%,$&%5'&#'#([&/,A%E/,T*/"#'#(
g%1,(b%KA1(+)/-#(7BCBFEBCFG<(
W&4/",(8'(='&&"'&(7BCBBEBCXX<(
gK*'#(g/,##',(((
(
bLA*'()'(:A1R/4'(7BCD]<((
'$(,%-4&'()'(2%*[(7BCDX<(
:A1R/4'(7BCD]<(,%$'(*/(.I&"%)"A"$I()'(B\(/,#(',5"&%,(JK'(
2%*[(7BCDX<(5/(&'$&/A'&(#K&(*/(.I&"%)'(BXDF(E(BCYGU((

9h'$(V%..*'&Ei"Z'/K(
.&'K5'(I*'A$&%-/T,I$"JK'()K(-%K5'-',$(/,,K'*(
2345#6#2378#9#23:5#;#<(&="#&*#=">&%.&#1,*-(=&.#?="0*&.##
1@#5A#0->&'B%&#23A5(
(
M"'*/('#$()IA%K5'&$'(*'(GX([I5&"'&(BCGY(./&(K,(%vA"'&(/K$&"A1"',N(M"'*/N(`(g%#'.1#$/)$U(
B\(l%K&#(.*K#($/&)N('**'('#$()IA%K5'&$'(`(q/&#'"**'(./&(O/,4/&$N('$(&'A%,,K$(JKr'**'(
I$/"$(*/(-S-'(JK'(A'**'()IA%K5'&$'(./&(q%,$/T,'N(`(8"-%T'#N(*'(C(-/&#(BXXG('$(./&(
6%,#N(`(q/&#'"**'N(*'(F(,%5'-4&'(BC\cU(
(
BC]G(E(V/-%"#'/K(A/*AK*'(*/($&/l'A$%"&'()'(M"'*/('$(A%,#$/$'(JKr'**'(A&%"#'&/(*r%&4"$'(
)'(*/(0'&&'(*'(GF(%A$%4&'(BC]G(.'K(/5/,$(-",K"$U(8'(./##/T'(#r'h'A$K'&/()/,#(*'(.*/,N(
K,(.'K(',()')/,#()'(*r%&4"$'()'(*/(0'&&'N(`(DNY(&/L%,#($'&&'#$&'#N(*/(A%-/(/L/,$(K,(
)"/-@$&'()'(cN](&/L%,#($'&&'#$&'#U(eI#K*$/$#(/..KLI#()'($%K$'(*r/K$%&"$I(#A"',$"^JK'N(
lK#JKr`(A'(JKr+&/T%N()/,#(*rAnnuaire!du!Bureau!des!Longitudes!.%K&(BC]GN(IA&"5w$(JK'(
*/(0'&&'(,r/&&"5'&/"$(',(A'(.%",$(JK'(*'(GX(,%5'-4&'(/K(-/$",N(Ar'#$E`E)"&'(.*K#()rK,(
-%"#(/.&@#(*'(./##/T'()'(*/(A%-@$'U(
(
BCDY(E(VI)%K4*'-',$()'(M"'*/(76(m(YNYG(/,#N(Jm\NCY(W+N(.mYNBF(W+<(5K(',(BCDY('$(
BCcGU(8'(B](l/,5"'&(BCDYN(*/(A%-@$'('#$(A%K.I'(',()'KaU(8'(B\([I5&"'&N()Il`(GD\U\\\(
p-(',$&'(*'#()'KaU(i",([I5&"'&N(q/K&L(72/#1",T$%,<(/.'&_%"$(K,(]@-'(.%",$(
*K-",'KaN(*/(A%-@$'(.&",A"./*'(/L/,$(](JK'K'#()%,$(*rK,'()"&"TI'(5'&#(*/()'Ka"@-'(
A%-@$'U((
(
BCcG(E(8'#()'Ka(A%-@$'#(&'5"',,',$N(A'$$'([%"#(#I./&I'#()'(GUD\\U\\\(p-U((
BCcFN(BCYc(j(*/(A%-@$'(,r/(./#(I$I(&'5K'U(W,(/AA")',$(T&/5'(/()K(*K"(/&&"5'&U(
(
:%"&I'()K(GX(,%5'-4&'(BCXG(j(averse()rI$%"*'#(^*/,$'#(7]\\\(x(1'K&'<(
n(;,$',#'(-'$'%&()"#.*/L#(R'&'(/*#%(,%$')()K&",T($1'(A%-'$r#(,'a$('a.'A$')(
&'$K&,#(",(BCCc(7BcN\\\(.'&(1%K&<N(BCFG(7YN\\\(.'&(1%K&<N(/,)(BCFF(7Bc\(.'&(1%K&<U(
Q%(,%$/4*'(-'$'%&(&/$'#(%AAK&&')(",($1'(L'/&#($1/$([%**%R')(o(
(
VrW&/,K#(`(Q'.$K,'(
(
((
(D\(/,#(/.&@#(*/()IA%K5'&$'()yW&/,K#(./&(!'&#A1'*(7BXCB<N(*'#(I.1I-I&")'#()'(
.%#"$"%,()yW&/,K#()"h@&',$()'(lK#JKy`(By()y/&A()'#(A%%&)%,,I'#(AI*'#$'#(
%4#'&5I'#U(8y'a"#$',A'()yK,(A%&.#(-/##"[(.'&$K&4/$'K&(7K,'(.*/,@$'(
#K..*I-',$/"&'('#$(/4%&)I'(`(*/([&%"#(',(i&/,A'('$(/K(e%L/K-'(W,"U(
((
((
g%1,(b%KA1(+)/-#(7BCBFEBCFG<(
W&4/",(g'/,Eg%#'.1(8'(='&&"'&(7BCBBEBCXX<(
(
6&I)"A$"%,(',(BCD]N(%4#'&5/$"%,(',(#'.$UBCDY(./&(*/**'-/,)(g%1/,,(
O%$$[&"')(O/**'(7BCBGEBFB\<N(/#$&%,%-'(`(M'&*",(.K"#()"&'A$'K&()'(
*34#'&5/$%"&'()'(M&'#*/K(72&%A*/R<N(`(Bz()'(#/(.%#"$"%,(.&I5K'N()/,#(
*/(A%,#$'**/$"%,()K(='&#'/K(
(
8/*/,)'(/5/"$(%4#'&5I(Q'.$K,'((
#K&(#'#(A/1"'&#()y%4#'&5/$"%,(
*'#(C('$(B\(-/"(BXFcU(
((
BY(/%{$(BCcC(E(6&'-"@&'(*"/"#%,((
./&(A|4*'(',$&'(*;&*/,)'('$(*'#(9$/$#EW,"#(
7#'()I&@T*'(',(K,(-%"#<(((
((
+)&'##'()'(BX\(-%$#()'(*/(e'",'(="A$%&"/(/K(
.&I#")',$(MKA1/,/,(7BCcXEBCYB<((
((
C+&#D%&"*#E".*&%0F#2388#
(
n(i%&($1',N($1'(./&/**/a(%[(=',K#([&%-($1'(#K,(-/L(4'([%K,)(4L($1'(-'$1%)(;(lK#$(
'a.*/",')N(/,)(/**(&'JK"&')(%4#'&5/$"%,#(R"**(4'([/A"*"$/$')(4L(}$1"#(./&/**/a~(4'",T($1&''(
$"-'#(/#(-KA1(/#($1/$(%[($1'(#K,N(#%($1/$([&%-($1"#(.1',%-',%,(/,L(-%&$/*(-/L(T/",(/,(
K,)'&#$/,)",T(%[($1"#(p,%R*')T'U(o(
7•<(n(01"#(#"T1$N(R1"A1("#(4L([/&($1'(,%4*'#$(/#$&%,%-L(/h%&)#N(*"p'($1'(#'AK*/&(T/-'#N("#(
)',"')($%(-%&$/*#([%&(/(R1%*'(A',$K&LN(4L($1'(#$&"A$(*/R#(%[(-%$"%,U(;$(R"**(4'(/[$'&R/&)#(
#1%R,N($1/$(4L($1"#(%4#'&5/$"%,(/*%,'N($1'()"#$/,A'(%[($1'(#K,N([&%-($1'('/&$1N(-"T1$(4'(
)'$'&-",')(R"$1($1'(T&'/$'#$(A'&$/",$LN(R1"A1N(%,(/AA%K,$(%[($1'(./&/**/a(%$1'&R"#'(JK"$'(
",#',#"4*'N(1/#(,%$(1"$1'&$%(4'',(.&'A"#'*L()'^,')U(o(
!/**'LN(e%L/*(:%A"'$LN(](%A$%4&'(BYFBU(
(
(
(
Frances !
Amiral
Mouchez!
camp, !
St-Paul Island,!
1874 transit!
T. Widemann - J. Patrimoine -
16/09/12!

BCDE2?;$*!F3&*G&?'4!24!H&*''4*!&)!H&D$*5!'I&;$*!24!J$K45!-6.L!
T. Widemann - J. Patrimoine -
16/09/12!
H&*''4*'!D#$I$+3&D#?M!34@$=@435!&!
D34M)3'$3!$F!M?*4%&I$+3&D#!N!!
T. Widemann - J. Patrimoine -
16/09/12!
6*/JK'#(.1%$%#(W:(Q/5/*(34#'&5/$%&L(
8'(./##/T'()'(BCCG(#'&/(*r%AA/#"%,()'(,%-4&'K#'#(
'a.I)"$"%,#U((
8'#(i&/,_/"#(%&T/,"#@&',$()"a(-"##"%,#(j((
*rw*'()r!/€$"(7b/**/,)&'/K<N((
q'a"JK'(7M%KJK'$()'(*/(O&L'<N((
q/&$","JK'(70"##'&/,)N(M"T%K&)/,N(6K"#'Ka<N((
i*%&")'(7A%*%,'*(6'&&"'&<N((
:/,$/Eb&KZ()'(6/$/T%,"'(7A/."$/",'()'(i&IT/$'(i*'K&"/"#<N((
b1"*"(7*"'K$',/,$()'(5/"##'/K()'(M'&,/&)"@&'#<(N((
b1K4K$(7!/$$<N((
e"%EQ'T&%(76'&&%$",N(*'()"&'A$'K&()'(*r%4#'&5/$%"&'()'(Q"A'<N(
b/.(!%&,(7*"'K$',/,$()'(5/"##'/K(b%K&A'**'E:','K"*<N((
M&/T/)%(7*"'K$',/,$()'(5/"##'/K(6'&&",<U(
T. Widemann - J. Patrimoine -
16/09/12!
Nagasaki, 1874 (Davidson, près de la station de Janssen) !
T. Widemann - J. Patrimoine -
16/09/12!
Venus Express 28th Science Working
Team, June 4-5 2012, Longyearbyen,
Svalbard!
O*I43*&;$*&=!P43?2?&*!Q$*F434*M45!!
R&'#?*+I$*!SQ5!-66L!
Venus Express 28th Science Working
Team, June 4-5 2012, Longyearbyen,
Svalbard!
Conférence de Washington, octobre 1884
25 pays fixent le méridien
origine à celui passant par
Greenwich, relié par
télégraphie au reste du
monde, malgré lopposition
de la France (Janssen).
Il y eut pour lAngleterre 4
méridiens successifs,
séparés de quelques
mètres : Flamsteed (1675),
Halley (1725), Bradley
(1750), enfin Airy (1851).
Le méridien de Paris, salle
Cassini de lObservatoire,
reste utilisé par la France
jusquaprès lentente
cordiale (1904). Adoption loi
du 9 mars 1911