สำนักราชบัณฑิตยสภา

«“√ “√ √“™∫— ≥±‘µ¬ ∂“π ªï ∑’Ë Ú˜ ©∫— ∫∑’Ë Ú ‡¡.¬.-¡‘ .¬. ÚıÙı π‘ æπ∏å ∑√“¬‡æ™√ Ùı˜ Abstract Standard Time for Thailand Nibondh Saibejra Fellow, the Academy of Science, the Royal Institute, Thailand Amean solar day is about four minutes longer than a mean sidereal day owing to the motion of the Earth around the sun. It is the mean solar day that is divided into 24 hours and is used in our daily life. The 0˚ longitude passing though Greenwich village in London was accepted internation- ally as the prime meridian in 1884. The standard time of England, using 0˚ longitude, is also known as UT (universal time). The standard times of the countries east of England are ahead of UT, while those of the countries west of England are behind. It has been international practice that the longi- tude passing through a country that is divisible by 15 or 7.5 should be used to represent the standard time of that country. This would make day time and night time in that country more natural, i.e. with the sun rising at about 6 a.m. and setting at about 6 p.m. The 105˚ east longitude, passing through Amnat Charoen and Ubon Ratchathani Provinces in northeastern Thailand, has been used to repre- sent the standard time of the country since 1919. This means that Thai standard time is seven hours ahead of UT, which is more suitable for Thailand than the zone time which is eight hours ahead of London, used by many countries such as China and Singapore. Key words : standard time, Thailand ‡∑à “°— ∫‡√“‰¡à ¡’ §«“¡√⟠§«“¡‡¢â “„® ‡°’Ë ¬«°— ∫‡√◊Ë Õ߇«≈“¡“µ√∞“π‡≈¬. æ√–∫“∑ ¡‡¥Á ®æ√–®Õ¡‡°≈â “‡®â “ Õ¬àŸ À— « ≈â π‡°≈â “œ √— ™°“≈∑’Ë Ù æ√–∫‘ ¥“ ·Àà ß«‘ ∑¬“»“ µ√å ‰∑¬∑√ß„™â ‡«≈“ ¡“µ√∞“π∑’Ë ¥’ °«à “ªí ®®ÿ ∫— π§◊ Õ „™â ‡«≈“ ¡“µ√∞“πµ“¡≈Õß®‘ ®Ÿ ¥ Ò Õß»“ µ–«— πÕÕ° ∑’Ë ºà “π„°≈â æ√–π§√§’ √’ ®— ßÀ«— ¥ ‡æ™√∫ÿ √’ ·≈–°√ÿ ߇∑æ¡À“π§√. „π ¡— ¬°à Õ𧫓¡µ°≈ß√–À«à “ߪ√–‡∑» ∑’Ë „Àâ ‡ â π≈Õß®‘ ®Ÿ ¥  Õß»“ ºà “π°√’ π‘ ™ °“√°”À𥇠â π≈Õß®‘ ®Ÿ ¥  Õß»“ ∫π ‚≈°„π ¡— ¬π—È π ‡ªì π°“√·¢à ߢ— π°— π ∑“ߪí ≠≠“√–À«à “ß¡À“Õ”π“®Õ— ß°ƒ… ·≈–¡À“Õ”π“®Ω√—Ë ß‡» ´÷Ë ßµâ Õß°“√„Àâ ‡ â π≈Õß®‘ ®Ÿ ¥  Õß»“ ºà “π°√ÿ ߪ“√’ ‡™à 𠇥’ ¬«°— π. „π∑’Ë ÿ ¥Ω√—Ë ß‡» ¬Õ¡Õ— ß°ƒ… ‚¥¬¡’ ¢â Õ·¡â «à “Õ— ß°ƒ…µâ Õß„™â ¡“µ√“ ™—Ë ßµ«ß«— ¥‡ªì π√–∫∫‡¡µ√‘ °µ“¡Ω√—Ë ß‡» „Àâ ‡ªì π “°≈¥â «¬ ‡ â π≈Õß®‘ ®Ÿ ¥  Õß»“ ®÷ ßÕ¬à Ÿ ∑’ Ë Õ— ß°ƒ… à «π‡ â π≈Õß®‘ ®Ÿ ¥Õ◊ Ë πÊ °Á «— ¥‡ªì π¡ÿ ¡Àà “ß‰ª∑“ßµ–«— πÕÕ°·≈– µ–«— πµ° ‚¥¬¡’ ‡ â πÀ≈— °Ê ∑’Ë À“√¥â «¬ Òı ≈ßµ— « π’Ë ‡ªì π¢â Õµ°≈ß√–À«à “ß ª√–‡∑». °“√µ—È ß‡«≈“¡“µ√∞“π®÷ ߇ªì π ‡√◊Ë Õß»— °¥‘Ï »√’ ∑“ß«‘ ™“°“√¢Õߪ√–‡∑» ‚¥¬·∑â ·≈–‡√◊Ë Õ߇«≈“‡ªì π«‘ ™“°“√ ∑“ߥ“√“»“ µ√å . ºâŸ ‡¢’ ¬π¡’ §«“¡‡ÀÁ π«à “ª√–‡∑» Õ“‡´’ ¬πÕ◊Ë π ‚¥¬‡©æ“–¡“‡≈‡´’ ¬ ‘ ߧ‚ª√å ·≈–∫“ß à «π¢ÕßÕ‘ π‚¥π’ ‡´’ ¬ Õ¬à Ÿ „π‡¢µ‡«≈“¡“µ√∞“π Òı Õß»“ µ–«— πÕÕ°‡™à π‡¥’ ¬«°— π°— ∫ª√–‡∑»‰∑¬ ª√–‡∑»¥— ß°≈à “«®÷ ߧ«√ª√— ∫‡«≈“ ¡“µ√∞“π¡“‡ªì π·∫∫¢Õ߇√“ ·≈â « æ«°‡¢“®–æ∫«à “™’ «‘ µ§«“¡‡ªì πÕ¬àŸ ®–‡¢â “°— ∫∏√√¡™“µ‘ ∑’Ë ‡°’Ë ¬«°— ∫‡«≈“‰¥â –¥«°¢÷È π¥’ ¢÷È π°«à “∑’Ë ‡ªì πÕ¬àŸ „πªí ®®ÿ ∫— π ·πà πÕπ. °≈à “«‚¥¬ √ÿ ª ‡«≈“¡“µ√∞“π ¢Õߪ√–‡∑»‰∑¬∑’Ë ‡√Á «°«à “‡«≈“Õ— ß°ƒ… ˜ ™—Ë «‚¡ß‡ªì π¢Õߥ’ ·≈–∂Ÿ °µâ Õßµ“¡ À≈— °«‘ ™“°“√Õ¬à Ÿ ·≈â « ‡ªì π ‘ Ë ß∑’ Ë §π‰∑¬ ∑ÿ °§π§«√¿“§¿Ÿ ¡‘ „® ‡æ√“–‡À¡“– ¡ ¥â «¬ª√–°“√∑—È ßª«ß ‚¥¬‡©æ“–‡ªì π ∏√√¡™“µ‘ ¡“°∑’Ë ÿ ¥ ®÷ ߉¡à §«√‡ª≈’Ë ¬π ‡ªì πÕ¬à “ßÕ◊Ë π´÷Ë ß‰¡à ‡ªì πÀ≈— ° “°≈·≈– ‰¡à ∂Ÿ °µâ Õß∑“ß«‘ ™“°“√.