Prof P Rinawma
1. Introduction: Kan hriat theuh angin kan awmna lei hi khawthlang lam atangin khawchhak zawngin a vir vel reng a, darkar 24 chhungin vawi khat a virchhuak hman a, chumi rual chuan ni velah a kal kual reng bawk a. Kum khat chhungin ni khi vawikhat a hel chhuak hman bawk a ni. Kan leiin ni a helchhuah hun chhung hian khawvel hmun hrang hrangah sik leh sa awmdan pawh nasa takin a danglam a ni. Kan lei hian energy leh light hi ni atanga a hmuh chauh a nih avangin khawvel hmun hrang hranga a semdarh dan pawh a inang chiah lova, chuvangin, mithiamte chuan khawvel hi zone hrang hrangah an then sawm a, chungte chu - Torrid zone, Temperate zone leh Frigid zone te an ni. Torrid zone – tropical leh sub-tropical zone huam chhung a awm ram ten energy leh light an hmu tha ber a, frigid zone-a awm ramte chuan ni eng an hmuh dan a tlem deuh avangin a lum leh a vawh lamah pawh zone dang ai chuan nasa takin a danglam a ni. Chutiang bawkin ram leilung pianhmang (phaizawl leh tlangram) a zir pawhin a danglam ve bawk.
Kan chenna lei hi ama axis-a a vir kual reng avanga chhun leh zan lo awm a nih angin chhim tawp leh hmar tawp bul vel a awm te chauh lo chuan chhun leh zan hi kan nei vek a ni. Nimahsela, kan lei axis hi 23.50 a plane of the orbit-a a awn (inclined) avang erawh chuan hmun tina darkar 12 chhun leh darkar 12 zan ni mai tur chu a ni thei lo a ni. Equator hmar lam leh chhim lam ram leh hmartawp leh chhim tawp ram te’n chhun leh zan kan neih dan a inang thei lo a ni. Tin, kan leiin ni a hel kual reng avang pawhin kum khat chhunga chhun leh zan kan neih rei leh rei loh pawh hi a inthlak danglam ve reng bawk.
Lei hi a mum a nih avangin hmun awmna lantir hi geographer-ten harsatna an tawh pakhat a ni a. A teh theih dan rintlak ber chu centre angle chhutchhuah a\angin a ni. Lei a lai taka hawlhtlanga axis degree 900(right angle) a ni zel a, chu chu Great Circle vuah a ni. He Great Circle a\ang hian chhim tawp leh hmar tawp hlat dan a inang chiah a. He Great Circle hi Equator tih a ni a, Equator a\ang hian chhimtawp leh hmartawp hlat zawng teh a ni. Chutichuan equator a\angin Great Circle parallel zelin parallel lines siam a ni a, chu parallel lines te chu lines of latitude kan tih hi a ni. North pole chu 900N latitudes a ni a, south pole chu 900S latitudes a ni. East leh west zawnga han then hrang tur in Equator (Great Circle) ang hi a awm ve lova. Map tam ber hi England ram Greenwich a\anga teh a ni deuh ber. Greenwich kaltlanga line rin chu Prime Meridian tih a ni. Longitude degree chu Prime meridian a\anga a angle hlat dan anga siam a ni. Khawvel pumpui hi Prime meridian a\angin, khawthlang a\anga khawchhak hualin longitude 3600-ah then a ni a, longitude degree thuhmuna awmte chuan a tlangpui thuin (north pole leh south pole) tih loh ah chuan ni vanlaizawl (midday) hi a in ang tlang a, chuti chuan longitude degree thuhmun a awmte chuan local time ang khat an nei a ni.
Longitude degree thuhmuna awmte hian mahni local time an hman \heuh chuan a buaithlak lutuk dawn avangin a siam rem dan zawn a ni a. Ram bung khat a chengte’n local time hrang hrang hman a nih chuan khawchhak zawng emaw khawthlang zawngin emaw, zin chhuah chuan 10 longitude zelah sana minute li zelin herh hma emaw paih emaw a ngai \hin. Hmanlai hunah chuan mi an zin kual vak vak lemloh avangin harsatna a awm teh chiam lo. Nimahsela Transport leh communication, a bikin rail road leh air transport lamah kum zabi 19-na tawp lam a\angin hma a lo sawn tak zel avangin problem hrang hrang a lo awm ta a. Railway time keeper te’n sana chi li chi nga an hman te a lo \ul ta. North America khuan Europe leh khawmualpui dangte aiin harsatna an ngah leh zual a ni. Canada mi Sir Sandford Fleming chuan local time tam lutuk hman ai chuan a lo awlsam zawk nan ram bung hrang hrang te’n standard time neih a \ul thu a au chhuahpui a, kum 1884 khan khawvel hi time zone darkar khat emaw, 150 longitude dan zelah time zone siam rem tih a ni. Time zone thuhmuna awmte chuan hun thuhmun an nei ang a, an sana pawh time zone danga an kal chuahin tihdanglam a ngai chauh ang. Standard time kan hman hian local time leh standard time a inmil loh dan ai chuan harsatna tam tak a su kiang zawk a ni.
Khawvel pumpui hi Standard Time Zone 25 ah \hen a niin UTC time (Coordinated Universal Time (tunhma chuan GMT ti a hriat) mila siam a ni. Entirna +5 hours or -10 hours to UTC. UTC time-ah 12:00 noon a nihin +5 zone ah chuan 17:00 or 5:00 p.m) a ni ang.
Daylight Saving Time (DST) chu miten tlai lamah darkar khat tal ni eng an hman theih dan ruahman a ni. DST hi kan sana darkar khata kan herh hma hian kan nei thei a ni. Electric power hman pawh nasa takin a hniam ang. DST (Daylight Saving Time) chungchang ah chuan DST emaw, summer time ti a Britain a an sawi \hin hi William Wilette (1857-1915), London khaw hmasawn nana thawk \hin Petts Wood Kent a cheng \hin chuan 1907 khan pamphet te buatsaihin MP rualte, khaw roreltute, sumdawngte leh pawl hrang hrangte hnenah a thawn a, a thu tlangau pui ber chu kum chanve dawn lai hi darkar tam tak kan muthilh hlan hian ni eng a kal ral a, hna kan han thawh zawh tawh hnua ina kan han haw thlen meuh chuan niin min liamsan leh mai \hin, a ti a. A rawtnaah chuan sana hi minute 20-in April thlaa Sunday vawi 4 hi sawn hma ni se, chumi vek chu September Sunday 4 ah hian paih leh ni se, hriselna kawng leh economy ah pawh kan hlawkpui zawk ang, a ti a. Chu bakah chuan electric eng a senso pawh hi £ maktaduai hnih leh a chanve lain a tla thla bawk ang, a ti a. He thil hi miten an ngai thu tak vak lo chungin Daylight Saving Bill (1909) siam a ni a, nimahsela Indopui hma chuan hman zui a ni ta chuang lo a ni. April 1916 ah Daylight Saving Time hi indo puahchaha economy tihsan nan British ho chauh lo pawhin kar reilote chhungin Europe ram tam tak chuan an hmang a. Vanduaithlak takin William-a chu a kum leh ah a thih tak avangin ngaihsak zui a ni ta lova. Indopui a lo tawp chuan an hmang zui leh ta lo a ni.
Kum 1968-1971 chho ah khan British ho in enchhin nan BST (British Standard Time) kum tluana hman a tan an duang a, nimahsela Scotland School naupang ten thim hnuah School kalte a tul \hin avangin chu an enchhinna chu an ti tawp leh ta a ni. Thlasikah chuan UTC (GMT), nipuiah chuan BST an zawm a ni.
USA khu 52030' West longitude leh 165030' West longitude inkarah a awm a, Time zone pariat laiin a tan tlang a. A ram khawthlang tawp a\anga khawchhak tawp khu 1130 in a in thlau a, hun thuah pawh khawthlang tawp leh khawchhak tawp chu darkar 7 leh minute 30 in a in thlau a ni. Chumi anih avangin Standard Time pawh panga (New York, Mexico City/ Chicago, Denver, Los Angeles, Alaska) an nei a ni.
USSR (Russia) chu 450 E Longitude leh 1600 E Longitude inkarah awmin Time Zone pakua lain a tan tlang a, khawthlang tawp atanga khawchhak inkar chu 1150-in a inthlau a, hun thuah pawh darkar kua lain a inthlau a ni. Standard Time pawh pali (Moscow, Yekaterinburg, Krasnoyarsk leh Yakutsk) an hmang a ni.
China khi 750 E Longitude leh 1350 E Longitude inkar ah a awm a, Time Zone pali laiin a tan tlang a, khawthlang a\anga khawchhak ber chu hun thuah pawh darkar thumin a inthlau a ni. Standard Time pakhat (China Standard Time) an hmang.
2.India in Time Zone pakhat a hman avanga NE India a nghawng dan: Asia khawmualpui hian time zone 11 an hmang a, he time zone hi UTC (GMT) +4 atanga UTC (GMT) +10 ah a awm a. Asia ram tam be rte chuan Daylight Saving Time hi an hmang lova, Asia ram a\anga Daylight Saving Time hmang ram te chu – Armenia, Azerbaijan, Mongolia, Pakistan leh Russia te an ni a. Middle East (Asia minor or South West Asia) Daylight Saving Time hmang ram te chu – Iraq, Israel, Jordan, Lebanon, Palestinian leh Syria te an ni.
India hi khawvela ram zau ber pasarihna niin mihring tam ber pahnihna a ni bawk a. Khawvel pumpui a 2.4% hi a awh a, khawvel mihring 16% hi India mi kan ni bawk a ni. A ram pum hian Equator hmar lamah a awm. India ram hi 68°7' leh 97°25' E longitudes inkarah leh 8°4' leh 37°6' N latitudes-ah a awm. India khawchhak tawp leh khawthlang tawp ber hmun te chu darkar 1 leh minute 56 in a inthlau a. NE India central meridian 93°30' hi (IST) 82°30' nen hian hun thuah 44 minute-in a inthlau a, Western India central meridian 75°15' E Longitude hi IST 82°30' E longitude hi minutes 25 in an in thlau a. Chutichuan NE India central meridian chu (IST) 82030' ai in 44 minutes in a hma a, chutih laiin Western India central meridian chu 25 minues in (IST) aiin a tlai thung a ni.
India ram hian Daylight Saving Time a hman loh avangin NE India a chengte tan hian Central leh West India a chengte ai hian hnathawh hun chhung hi kan nei tlem zawk a ni. A chhan leh vang chu nipui lain Equator hmar lam ram te chu zan aiin chhun hun arei zawk a, mipui tam ber NE India a chengte tiamin sana mila hun kan hman \hin avangin zing ni chhuah hnu fe a\anga hna thawk \anin tlai nitlak thlengin hna an thawk a, thilsiamna hmuna thawkte phei chu khaw thim hnu reife thleng pawhin an thawk a ni. Central India leh Western India a chengte chuan zing a\anga tlai thlengin ni eng hnuaiah hnatawhna hun an nei tam zawk a ni.
Sun Elevation Angle chungchangah pawh NE India leh Central India hi a hrang daih bawk a. Central India a Midday (12:00 noon) a nih chiahin NE India-ah chuan 12:00 noon IST ah chuan ni chu khawthlang lamah a inher daih tawh \hin avangin hun hman kawngah NE India hian harsatna a tawk \hin a ni.
NE India-a school naupang te, thilsiamna hmun a thawk te, company leh government office a thawkte hian thlasik lai hian harsatna an tawk bawk a, office zing dar 9 a\anga tlai lam dar 5 thleng thawh a ngaih si a vangin hnathawhna hmun khawthim dawnah chhuahsan a ngai \hin a, central India a chengte tan erawh chuan tlai dar 5 hi a la tlai lutuk loh avangin harsatna an nei ve lem lo a ni.
A chunga kan han tarlan te khi India in Standard Time pakhat chauh a hman avanga North East India State ten harsatna kan neih \henkhat te an ni a. Chutihlai chuan India hian Standard Time pahnih Western Standard Time leh Eastern Standard Time nei pawh ni ta teh reng se, a \hatlohna pawh sawi tur a tam thei viau tho ang. A nihna takah chuan Time Zone avangin ram hi a hausain a rethei hranpa lova, geographical factors tam tak vang a ni zawkin a lang. DST (Daylight Saving Time) hmang turin NE India State te hian thei tawp chhuah ila kawng engkimah hma kan sawn zawk ngei ang.
Kan chenna lei hi ama axis-a a vir kual reng avanga chhun leh zan lo awm a nih angin chhim tawp leh hmar tawp bul vel a awm te chauh lo chuan chhun leh zan hi kan nei vek a ni. Nimahsela, kan lei axis hi 23.50 a plane of the orbit-a a awn (inclined) avang erawh chuan hmun tina darkar 12 chhun leh darkar 12 zan ni mai tur chu a ni thei lo a ni. Equator hmar lam leh chhim lam ram leh hmartawp leh chhim tawp ram te’n chhun leh zan kan neih dan a inang thei lo a ni. Tin, kan leiin ni a hel kual reng avang pawhin kum khat chhunga chhun leh zan kan neih rei leh rei loh pawh hi a inthlak danglam ve reng bawk.
Lei hi a mum a nih avangin hmun awmna lantir hi geographer-ten harsatna an tawh pakhat a ni a. A teh theih dan rintlak ber chu centre angle chhutchhuah a\angin a ni. Lei a lai taka hawlhtlanga axis degree 900(right angle) a ni zel a, chu chu Great Circle vuah a ni. He Great Circle a\ang hian chhim tawp leh hmar tawp hlat dan a inang chiah a. He Great Circle hi Equator tih a ni a, Equator a\ang hian chhimtawp leh hmartawp hlat zawng teh a ni. Chutichuan equator a\angin Great Circle parallel zelin parallel lines siam a ni a, chu parallel lines te chu lines of latitude kan tih hi a ni. North pole chu 900N latitudes a ni a, south pole chu 900S latitudes a ni. East leh west zawnga han then hrang tur in Equator (Great Circle) ang hi a awm ve lova. Map tam ber hi England ram Greenwich a\anga teh a ni deuh ber. Greenwich kaltlanga line rin chu Prime Meridian tih a ni. Longitude degree chu Prime meridian a\anga a angle hlat dan anga siam a ni. Khawvel pumpui hi Prime meridian a\angin, khawthlang a\anga khawchhak hualin longitude 3600-ah then a ni a, longitude degree thuhmuna awmte chuan a tlangpui thuin (north pole leh south pole) tih loh ah chuan ni vanlaizawl (midday) hi a in ang tlang a, chuti chuan longitude degree thuhmun a awmte chuan local time ang khat an nei a ni.Longitude degree thuhmuna awmte hian mahni local time an hman \heuh chuan a buaithlak lutuk dawn avangin a siam rem dan zawn a ni a. Ram bung khat a chengte’n local time hrang hrang hman a nih chuan khawchhak zawng emaw khawthlang zawngin emaw, zin chhuah chuan 10 longitude zelah sana minute li zelin herh hma emaw paih emaw a ngai \hin. Hmanlai hunah chuan mi an zin kual vak vak lemloh avangin harsatna a awm teh chiam lo. Nimahsela Transport leh communication, a bikin rail road leh air transport lamah kum zabi 19-na tawp lam a\angin hma a lo sawn tak zel avangin problem hrang hrang a lo awm ta a. Railway time keeper te’n sana chi li chi nga an hman te a lo \ul ta. North America khuan Europe leh khawmualpui dangte aiin harsatna an ngah leh zual a ni. Canada mi Sir Sandford Fleming chuan local time tam lutuk hman ai chuan a lo awlsam zawk nan ram bung hrang hrang te’n standard time neih a \ul thu a au chhuahpui a, kum 1884 khan khawvel hi time zone darkar khat emaw, 150 longitude dan zelah time zone siam rem tih a ni. Time zone thuhmuna awmte chuan hun thuhmun an nei ang a, an sana pawh time zone danga an kal chuahin tihdanglam a ngai chauh ang. Standard time kan hman hian local time leh standard time a inmil loh dan ai chuan harsatna tam tak a su kiang zawk a ni.
Khawvel pumpui hi Standard Time Zone 25 ah \hen a niin UTC time (Coordinated Universal Time (tunhma chuan GMT ti a hriat) mila siam a ni. Entirna +5 hours or -10 hours to UTC. UTC time-ah 12:00 noon a nihin +5 zone ah chuan 17:00 or 5:00 p.m) a ni ang.
Daylight Saving Time (DST) chu miten tlai lamah darkar khat tal ni eng an hman theih dan ruahman a ni. DST hi kan sana darkar khata kan herh hma hian kan nei thei a ni. Electric power hman pawh nasa takin a hniam ang. DST (Daylight Saving Time) chungchang ah chuan DST emaw, summer time ti a Britain a an sawi \hin hi William Wilette (1857-1915), London khaw hmasawn nana thawk \hin Petts Wood Kent a cheng \hin chuan 1907 khan pamphet te buatsaihin MP rualte, khaw roreltute, sumdawngte leh pawl hrang hrangte hnenah a thawn a, a thu tlangau pui ber chu kum chanve dawn lai hi darkar tam tak kan muthilh hlan hian ni eng a kal ral a, hna kan han thawh zawh tawh hnua ina kan han haw thlen meuh chuan niin min liamsan leh mai \hin, a ti a. A rawtnaah chuan sana hi minute 20-in April thlaa Sunday vawi 4 hi sawn hma ni se, chumi vek chu September Sunday 4 ah hian paih leh ni se, hriselna kawng leh economy ah pawh kan hlawkpui zawk ang, a ti a. Chu bakah chuan electric eng a senso pawh hi £ maktaduai hnih leh a chanve lain a tla thla bawk ang, a ti a. He thil hi miten an ngai thu tak vak lo chungin Daylight Saving Bill (1909) siam a ni a, nimahsela Indopui hma chuan hman zui a ni ta chuang lo a ni. April 1916 ah Daylight Saving Time hi indo puahchaha economy tihsan nan British ho chauh lo pawhin kar reilote chhungin Europe ram tam tak chuan an hmang a. Vanduaithlak takin William-a chu a kum leh ah a thih tak avangin ngaihsak zui a ni ta lova. Indopui a lo tawp chuan an hmang zui leh ta lo a ni.
Kum 1968-1971 chho ah khan British ho in enchhin nan BST (British Standard Time) kum tluana hman a tan an duang a, nimahsela Scotland School naupang ten thim hnuah School kalte a tul \hin avangin chu an enchhinna chu an ti tawp leh ta a ni. Thlasikah chuan UTC (GMT), nipuiah chuan BST an zawm a ni.
USA khu 52030' West longitude leh 165030' West longitude inkarah a awm a, Time zone pariat laiin a tan tlang a. A ram khawthlang tawp a\anga khawchhak tawp khu 1130 in a in thlau a, hun thuah pawh khawthlang tawp leh khawchhak tawp chu darkar 7 leh minute 30 in a in thlau a ni. Chumi anih avangin Standard Time pawh panga (New York, Mexico City/ Chicago, Denver, Los Angeles, Alaska) an nei a ni.
USSR (Russia) chu 450 E Longitude leh 1600 E Longitude inkarah awmin Time Zone pakua lain a tan tlang a, khawthlang tawp atanga khawchhak inkar chu 1150-in a inthlau a, hun thuah pawh darkar kua lain a inthlau a ni. Standard Time pawh pali (Moscow, Yekaterinburg, Krasnoyarsk leh Yakutsk) an hmang a ni.
China khi 750 E Longitude leh 1350 E Longitude inkar ah a awm a, Time Zone pali laiin a tan tlang a, khawthlang a\anga khawchhak ber chu hun thuah pawh darkar thumin a inthlau a ni. Standard Time pakhat (China Standard Time) an hmang.
2.India in Time Zone pakhat a hman avanga NE India a nghawng dan: Asia khawmualpui hian time zone 11 an hmang a, he time zone hi UTC (GMT) +4 atanga UTC (GMT) +10 ah a awm a. Asia ram tam be rte chuan Daylight Saving Time hi an hmang lova, Asia ram a\anga Daylight Saving Time hmang ram te chu – Armenia, Azerbaijan, Mongolia, Pakistan leh Russia te an ni a. Middle East (Asia minor or South West Asia) Daylight Saving Time hmang ram te chu – Iraq, Israel, Jordan, Lebanon, Palestinian leh Syria te an ni.
India hi khawvela ram zau ber pasarihna niin mihring tam ber pahnihna a ni bawk a. Khawvel pumpui a 2.4% hi a awh a, khawvel mihring 16% hi India mi kan ni bawk a ni. A ram pum hian Equator hmar lamah a awm. India ram hi 68°7' leh 97°25' E longitudes inkarah leh 8°4' leh 37°6' N latitudes-ah a awm. India khawchhak tawp leh khawthlang tawp ber hmun te chu darkar 1 leh minute 56 in a inthlau a. NE India central meridian 93°30' hi (IST) 82°30' nen hian hun thuah 44 minute-in a inthlau a, Western India central meridian 75°15' E Longitude hi IST 82°30' E longitude hi minutes 25 in an in thlau a. Chutichuan NE India central meridian chu (IST) 82030' ai in 44 minutes in a hma a, chutih laiin Western India central meridian chu 25 minues in (IST) aiin a tlai thung a ni.
India ram hian Daylight Saving Time a hman loh avangin NE India a chengte tan hian Central leh West India a chengte ai hian hnathawh hun chhung hi kan nei tlem zawk a ni. A chhan leh vang chu nipui lain Equator hmar lam ram te chu zan aiin chhun hun arei zawk a, mipui tam ber NE India a chengte tiamin sana mila hun kan hman \hin avangin zing ni chhuah hnu fe a\anga hna thawk \anin tlai nitlak thlengin hna an thawk a, thilsiamna hmuna thawkte phei chu khaw thim hnu reife thleng pawhin an thawk a ni. Central India leh Western India a chengte chuan zing a\anga tlai thlengin ni eng hnuaiah hnatawhna hun an nei tam zawk a ni.
Sun Elevation Angle chungchangah pawh NE India leh Central India hi a hrang daih bawk a. Central India a Midday (12:00 noon) a nih chiahin NE India-ah chuan 12:00 noon IST ah chuan ni chu khawthlang lamah a inher daih tawh \hin avangin hun hman kawngah NE India hian harsatna a tawk \hin a ni.
NE India-a school naupang te, thilsiamna hmun a thawk te, company leh government office a thawkte hian thlasik lai hian harsatna an tawk bawk a, office zing dar 9 a\anga tlai lam dar 5 thleng thawh a ngaih si a vangin hnathawhna hmun khawthim dawnah chhuahsan a ngai \hin a, central India a chengte tan erawh chuan tlai dar 5 hi a la tlai lutuk loh avangin harsatna an nei ve lem lo a ni.
A chunga kan han tarlan te khi India in Standard Time pakhat chauh a hman avanga North East India State ten harsatna kan neih \henkhat te an ni a. Chutihlai chuan India hian Standard Time pahnih Western Standard Time leh Eastern Standard Time nei pawh ni ta teh reng se, a \hatlohna pawh sawi tur a tam thei viau tho ang. A nihna takah chuan Time Zone avangin ram hi a hausain a rethei hranpa lova, geographical factors tam tak vang a ni zawkin a lang. DST (Daylight Saving Time) hmang turin NE India State te hian thei tawp chhuah ila kawng engkimah hma kan sawn zawk ngei ang.
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Mizo