{"id":1255,"date":"2020-12-13T21:01:22","date_gmt":"2020-12-13T14:01:22","guid":{"rendered":"http:\/\/weathervn.com\/?p=1255"},"modified":"2020-12-13T21:01:22","modified_gmt":"2020-12-13T14:01:22","slug":"mua-sao-bang-12-2020","status":"publish","type":"post","link":"https:\/\/vietweather.com\/index.php\/mua-sao-bang-12-2020\/","title":{"rendered":"\u201cM\u01b0a sao b\u0103ng\u201d 12\/2020"},"content":{"rendered":"
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HAAC – C\u00e2u l\u1ea1c b\u1ed9 Thi\u00ean v\u0103n nghi\u1ec7p d\u01b0 TP.HCM<\/strong><\/a><\/div>\n<\/div>\n
22 November at 13:14<\/a><\/span>\u00a0<\/span> \u00b7 <\/span><\/span><\/i><\/span><\/div>\n<\/div>\n<\/div>\n<\/div>\n
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Ch\u1ee7 \u0111\u1ec1 c\u1ee7a tr\u1ea1i thi\u00ean v\u0103n th\u00e1ng 12 t\u1edbi l\u00e0 \u201cM\u01b0a sao b\u0103ng\u201d, n\u0103m nay t\u00e2m \u0111i\u1ec3m c\u1ee7a tr\u1eadn m\u01b0a sao b\u0103ng Geminids \u0111\u00e1ng ch\u00fa \u00fd nh\u1ea5t n\u0103m n\u00e0y kho\u1ea3ng 12-13\/12 tr\u00f9ng th\u1eddi \u0111i\u1ec3m kh\u00f4ng tr\u0103ng \u201c New Moon\u201d, r\u1ea5t thu\u1eadn l\u1ee3i cho vi\u1ec7c quan s\u00e1t. Ch\u00fang ta h\u00e3y th\u1ea3o lu\u1eadn v\u00e0i c\u00e2u chuy\u1ec7n l\u00fd th\u00fa v\u1ec1 \u201cm\u01b0a sao b\u0103ng\u201d s\u1eafp t\u1edbi nh\u00e9:<\/div>\n<\/div>\n
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1. Sao b\u0103ng (meteor) l\u00e0 g\u00ec?<\/div>\n
Th\u1ec9nh tho\u1ea3ng s\u1ebd th\u1ea5y \u0111\u1ed9t nhi\u00ean xu\u1ea5t hi\u1ec7n m\u1ed9t v\u1ec7t s\u00e1ng l\u01b0\u1edbt qua r\u1ea5t nhanh tr\u00ean b\u1ea7u tr\u1eddi r\u1ed3i bi\u1ebfn m\u1ea5t. \u0110\u00f3 ch\u00ednh l\u00e0 sao b\u0103ng. Sao b\u0103ng ch\u00ednh l\u00e0 c\u00e1c m\u1ea3nh \u0111\u00e1\/b\u1ee5i b\u00ean ngo\u00e0i Tr\u00e1i \u0110\u1ea5t (meteoroid), \u0111i v\u00e0o b\u1ea7u kh\u00ed quy\u1ec3n c\u1ee7a h\u00e0nh tinh ch\u00fang ta v\u1edbi t\u1ed1c \u0111\u1ed9 r\u1ea5t nhanh (v\u00e0i ch\u1ee5c km\/s), ch\u00e1y s\u00e1ng t\u1ea1o th\u00e0nh v\u1ec7t, v\u00e0 \u0111a ph\u1ea7n ch\u00e1y s\u00e1ng h\u1ebft tr\u01b0\u1edbc \u0111i ch\u1ea1m t\u1edbi m\u1eb7t \u0111\u1ea5t.<\/div>\n
Do v\u1eady:<\/div>\n
– V\u00e0o b\u1ea5t k\u1ef3 \u0111\u00eam \u0111\u1eb9p tr\u1eddi n\u00e0o, c\u00e1c b\u1ea1n c\u0169ng c\u00f3 th\u1ec3 quan s\u00e1t \u0111\u01b0\u1ee3c sao b\u0103ng, t\u1eeb v\u00e0i v\u1ec7t t\u1edbi v\u00e0i ch\u1ee5c v\u1ec7t t\u00f9y \u0111i\u1ec1u ki\u1ec7n th\u1eddi ti\u1ebft, th\u1eddi \u0111i\u1ec3m quan s\u00e1t v\u00e0 vi\u1ec7c c\u00f3 quan s\u00e1t ch\u00fang \u0111\u00fang c\u00e1ch kh\u00f4ng n\u1eefa. Do \u0111\u00f3, quan s\u00e1t sao b\u0103ng c\u0169ng c\u1ea7n b\u1ea1n ph\u1ea3i c\u00f3 ch\u00fat k\u1ef9 n\u0103ng n\u1eefa nh\u00e9, HAAC lu\u00f4n nh\u1eadn \u0111\u01b0\u1ee3c c\u00e2u h\u1ecfi quen thu\u1ed9c r\u1eb1ng \u201csao b\u1ea1n b\u00ean c\u1ea1nh c\u1ee9 th\u1ea5y ho\u00e0i m\u00e0 m\u00ecnh th\u00ec kh\u00f4ng k\u1ecbp th\u1ea5y v\u1ec7t sao b\u0103ng n\u00e0o c\u1ea3?\u201d.<\/div>\n
– Do \u0111i v\u00e0o b\u1ea7u kh\u00ed quy\u1ec3n c\u1ee7a h\u00e0nh tinh ch\u00fang ta v\u1edbi v\u1eadn t\u1ed1c r\u1ea5t l\u1edbn, n\u00ean \u0111a ph\u1ea7n ch\u00fang ta ch\u1ec9 quan s\u00e1t c\u00e1c v\u1ec7t sao b\u0103ng trong th\u1eddi gian v\u00f4 c\u00f9ng ng\u1eafn ng\u1ee7i (v\u00e0i gi\u00e2y \u0111\u00e3 l\u00e0 hi\u1ebfm g\u1eb7p, v\u00e0 \u0111a ph\u1ea7n nh\u1ecf h\u01a1n 1 gi\u00e2y) m\u00e0 th\u00f4i, n\u00ean kh\u00f4ng k\u1ecbp c\u1ea5t l\u00ean b\u1ea5t k\u1ef3 l\u1eddi \u01b0\u1edbc n\u00e0o nh\u01b0 \u0111\u1ed3n \u0111\u1ea1i \u0111\u00e2u nh\u00e9.<\/div>\n
– K\u00edch th\u01b0\u1edbc c\u00e1c m\u1ea3nh \u0111\u00e1\/b\u1ee5i \u0111i v\u00e0o b\u1ea7u kh\u00ed quy\u1ec3n Tr\u00e1i \u0110\u1ea5t c\u00e0ng l\u1edbn, th\u00ec sao b\u0103ng c\u00e0ng s\u00e1ng [c\u00f3 v\u1ec7t sao r\u1ea5t s\u00e1ng g\u1ecdi l\u00e0 fireball (qu\u1ea3 c\u1ea7u l\u1eeda) hay \u0111\u1eb7c bi\u1ec7t s\u00e1ng\/th\u1eadm ch\u00ed c\u00f2n ph\u00e1t n\u1ed5 trong b\u1ea7u kh\u00ed quy\u1ec3n l\u00e0 bolide]; t\u1ea1o th\u00e0nh v\u1ec7t d\u00e0i, v\u00e0 khi \u0111\u1ee7 l\u1edbn \u0111\u1ec3 kh\u00f4ng b\u1ecb ch\u00e1y h\u1ebft trong b\u1ea7u kh\u00ed quy\u1ec3n, ph\u1ea7n c\u00f2n s\u00f3t l\u1ea1i khi t\u1edbi m\u1eb7t \u0111\u1ea5t ch\u00fang ta ch\u00ednh l\u00e0 \u201cthi\u00ean th\u1ea1ch\/meteorite\u201d.<\/div>\n<\/div>\n
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– \u201cK\u1ebb th\u00f9\u201d l\u1edbn nh\u1ea5t c\u1ee7a vi\u1ec7c quan s\u00e1t sao b\u0103ng: l\u00e0 th\u1eddi ti\u1ebft (tr\u1eddi m\u01b0a hay m\u00e2y) v\u00e0 \u00f4 nhi\u1ec5m s\u00e1ng, v\u00e0 b\u1ea1n c\u00f3 bi\u1ebft r\u1eb1ng ngu\u1ed3n \u201c\u00f4 nhi\u1ec5m s\u00e1ng t\u1ef1 nhi\u00ean\u201d t\u1eeb \u00e1nh tr\u0103ng ch\u00ednh l\u00e0 tr\u1edf ng\u1ea1i c\u1ef1c k\u1ef3 l\u1edbn cho vi\u1ec7c quan s\u00e1t c\u00e1c v\u1ec7t sao b\u0103ng. Do \u0111\u00f3, h\u00e3y tr\u00e1nh xa c\u00e1c th\u00e0nh ph\u1ed1 l\u1edbn (\u00f4 nhi\u1ec5m s\u00e1ng\/b\u1ee5i), ch\u1ecdn c\u00e1c v\u1ecb tr\u00ed c\u00f3 b\u1ea7u tr\u1eddi kh\u00e1 \u0111\u00eam t\u01b0\u01a1ng \u0111\u1ed1i trong v\u00e0 tr\u00e1nh ch\u1ecdn g\u1ea7n th\u1eddi \u0111i\u1ec3m tr\u0103ng tr\u00f2n \u0111\u1ec3 quan s\u00e1t.<\/div>\n<\/div>\n<\/div>\n
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2. M\u01b0a sao b\u0103ng (meteor shower)?<\/div>\n
Nh\u01b0 \u0111\u00e3 \u0111\u1ec1 c\u1eadp \u1edf tr\u00ean, ch\u00fang ta c\u00f3 th\u1ec3 quan s\u00e1t kh\u00e1 nhi\u1ec1u v\u1ec7t sao b\u0103ng t\u1ea1i b\u1ea5t k\u1ef3 \u0111\u00eam \u0111\u1eb9p tr\u1eddi n\u00e0o, nh\u01b0ng v\u1eabn hay \u0111\u1ecdc c\u00e1c th\u00f4ng tin r\u1eb1ng t\u1ea1i m\u1ed9t th\u1eddi \u0111i\u1ec3m nh\u1ea5t \u0111\u1ecbnh n\u00e0o trong n\u0103m s\u1ebd c\u00f3 m\u1ed9t s\u1ed1 tr\u1eadn \u201cm\u01b0a sao b\u0103ng\u201d di\u1ec5n ra.<\/div>\n
C\u00e1c tr\u1eadn m\u01b0a sao b\u0103ng di\u1ec5n ra t\u1ea1i th\u1eddi \u0111i\u1ec3m Tr\u00e1i \u0110\u1ea5t ch\u00fang ta \u0111i ngang qua \u0111\u00e1m b\u1ee5i v\u00e0 \u0111\u00e1 (m\u1ea3nh v\u1ee5n \u0111\u00e1 b\u1ee5i thi\u00ean th\u1ea1ch) \u0111\u1ec3 l\u1ea1i b\u1edfi c\u00e1c sao ch\u1ed5i hay ti\u1ec3u h\u00e0nh tinh trong qu\u00e1 kh\u1ee9. K\u1ebft qu\u1ea3 l\u00e0, thay v\u00ec ch\u1ec9 l\u00e0 m\u1ed9t v\u00e0i v\u1ec7t sao b\u0103ng, hay c\u00f2n g\u1ecdi l\u00e0 c\u00e1c \u201csao r\u01a1i-sao sa hay sao \u0111\u1ed5i ng\u00f4i\/shooting star\u201d m\u00e0 ch\u00fang ta th\u1ea5y v\u00e0o m\u1ed7i \u0111\u00eam tr\u1eddi trong, ch\u00fang ta s\u1ebd th\u1ea5y m\u1ed9t tr\u1eadn m\u01b0a sao b\u0103ng: h\u00e0ng ch\u1ee5c hay th\u1eadm ch\u00ed h\u00e0ng tr\u0103m c\u00e1c v\u1ec7t sao b\u0103ng d\u01b0\u1eddng nh\u01b0 xu\u1ea5t ph\u00e1t t\u1eeb c\u00f9ng m\u1ed9t h\u01b0\u1edbng tr\u00ean b\u1ea7u tr\u1eddi trong c\u1ea3 \u0111\u00eam.<\/div>\n
Sao ch\u1ed5i (comet) l\u00e0 nh\u1eefng thi\u00ean th\u1ec3 quay quanh M\u1eb7t Tr\u1eddi v\u1edbi qu\u1ef9 \u0111\u1ea1o Hyperbol ho\u1eb7c elip r\u1ea5t d\u1eb9t. Do \u0111\u01b0\u1ee3c c\u1ea5u t\u1ea1o ch\u1ee7 y\u1ebfu b\u1edfi b\u0103ng, b\u1ee5i v\u00e0 \u0111\u00e1 n\u00ean khi di chuy\u1ec3n t\u1edbi g\u1ea7n M\u1eb7t Tr\u1eddi, d\u01b0\u1edbi t\u00e1c \u0111\u1ed9ng c\u1ee7a gi\u00f3 M\u1eb7t Tr\u1eddi, c\u00e1c v\u1eadt ch\u1ea5t t\u1ea1o th\u00e0nh n\u00ean sao ch\u1ed5i n\u00e0y s\u1ebd tan r\u00e3 (comet breakup) v\u00e0 t\u1ea1o th\u00e0nh nh\u1eefng d\u1ea3i \u0111\u00e1\/b\u1ee5i (meteoroid swarm) \u0111\u1ec3 l\u1ea1i tr\u00ean qu\u1ef9 \u0111\u1ea1o di chuy\u1ec3n c\u1ee7a ch\u00ednh sao ch\u1ed5i \u0111\u00f3 trong kh\u00f4ng gian. Khi Tr\u00e1i \u0110\u1ea5t ch\u00fang ta trong qu\u00e1 tr\u00ecnh chuy\u1ec3n \u0111\u1ed9ng quanh M\u1eb7t Tr\u1eddi, \u0111i qua c\u00e1c v\u00f9ng kh\u00f4ng gian \u0111\u00f3, th\u00ec s\u1ed1 l\u01b0\u01a1ng \u0111\u00e1\/b\u1ee5i theo l\u1ef1c h\u1ea5p d\u1eabn di chuy\u1ec3n v\u00e0o trong b\u1ea7u kh\u00ed quy\u1ec3n h\u00e0nh tinh ch\u00fang ta s\u1ebd nhi\u1ec1u h\u01a1n th\u1eddi \u0111i\u1ec3m kh\u00e1c, l\u00e0m xu\u1ea5t hi\u1ec7n r\u1ea5t nhi\u1ec1u v\u1ec7t sao b\u0103ng h\u01a1n v\u00e0 \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 \u201cm\u01b0a sao b\u0103ng\u201d.<\/div>\n<\/div>\n
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V\u00ec qu\u1ef9 \u0111\u1ea1o c\u1ee7a Tr\u00e1i \u0110\u1ea5t v\u00e0 c\u00e1c sao ch\u1ed5i l\u00e0 x\u00e1c \u0111\u1ecbnh n\u00ean c\u00e1c giao \u0111i\u1ec3m l\u00e0 x\u00e1c \u0111\u1ecbnh tr\u00ean \u0111\u01b0\u1eddng \u0111i c\u1ee7a Tr\u00e1i \u0110\u1ea5t. Trong h\u00e0nh tr\u00ecnh chuy\u1ec3n \u0111\u1ed9ng quanh M\u1eb7t tr\u1eddi h\u00e0ng n\u0103m c\u1ee7a m\u00ecnh Tr\u00e1i \u0110\u1ea5t s\u1ebd \u0111i qua nh\u1eefng giao \u0111i\u1ec3m \u0111\u00f3 t\u1ea1i th\u1eddi \u0111i\u1ec3m x\u00e1c \u0111\u1ecbnh, do \u0111\u00f3 c\u00e1c tr\u1eadn m\u01b0a sao b\u0103ng l\u00e0 c\u00f3 chu k\u1ef3, v\u00e0 chu k\u1ef3 c\u1ee7a t\u1ea5t c\u1ea3 c\u00e1c tr\u1eadn m\u01b0a sao b\u0103ng \u0111\u1ec1u l\u00e0 1 n\u0103m.<\/div>\n
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3. T\u00e2m \u0111i\u1ec3m (radiant) v\u00e0 c\u1ef1c \u0111i\u1ec3m (peak) c\u1ee7a m\u01b0a sao b\u0103ng l\u00e0 g\u00ec?<\/div>\n
Khi quan s\u00e1t c\u00e1c tr\u1eadn m\u01b0a sao b\u0103ng ta th\u01b0\u1eddng c\u00f3 c\u1ea3m gi\u00e1c c\u00e1c v\u1ec7t sao b\u0103ng \u0111\u1ec1u xu\u1ea5t ph\u00e1t ho\u1eb7c h\u01b0\u1edbng v\u1ec1 m\u1ed9t khu v\u1ef1c c\u1ee5 th\u1ec3 tr\u00ean b\u1ea7u tr\u1eddi (xem \u1ea3nh), khu v\u1ef1c \u0111\u00f3 g\u1ecdi l\u00e0 t\u00e2m \u0111i\u1ec3m (radiant) c\u1ee7a tr\u1eadn m\u01b0a sao b\u0103ng. Trong c\u00e1c tr\u1eadn m\u01b0a sao b\u0103ng, t\u00e2m \u0111i\u1ec3m n\u00e0y n\u1eb1m trong khu v\u1ef1c c\u1ee7a ch\u00f2m sao n\u00e0o th\u00ec tr\u1eadn m\u01b0a sao b\u0103ng s\u1ebd \u0111\u01b0\u1ee3c g\u1ecdi theo t\u00ean ch\u00f2m sao \u0111\u00f3, v\u00ed d\u1ee5 m\u01b0a sao b\u0103ng Geminids \u2013 ch\u00f2m sao Gemini (Song Sinh), m\u01b0a sao b\u0103ng Leonids \u2013 ch\u00f2m sao Leo (S\u01b0 T\u1eed), m\u01b0a sao b\u0103ng Perseids \u2013 ch\u00f2m sao Perseus (Anh Ti\u00ean). C\u00e1c tr\u1eadn m\u01b0a sao b\u0103ng \u0111\u1ec1u c\u00f3 t\u00e2m \u0111i\u1ec3m xu\u1ea5t hi\u1ec7n nh\u01b0ng kh\u00f4ng c\u00f3 ngh\u0129a ch\u1ec9 \u1edf h\u01b0\u1edbng c\u1ee7a t\u00e2m \u0111i\u1ec3m m\u1edbi c\u00f3, ch\u1ec9 l\u00e0 quan s\u00e1t h\u01b0\u1edbng n\u00e0y s\u1ebd d\u1ec5 g\u1eb7p sao b\u0103ng h\u01a1n m\u00e0 th\u00f4i.<\/div>\n
Khi t\u00e2m \u0111i\u1ec3m n\u00e0y c\u00e0ng cao kh\u1ecfi ch\u00e2n tr\u1eddi bao nhi\u00eau th\u00ec c\u00e1c v\u1ec7t sao b\u0103ng xu\u1ea5t hi\u1ec7n c\u00e0ng nhi\u1ec1u, th\u1eddi \u0111i\u1ec3m quan s\u00e1t l\u00fd t\u01b0\u1edfng nh\u1ea5t l\u00e0 khi t\u00e2m \u0111i\u1ec3m \u1edf \u0111\u1ec9nh \u0111\u1ea7u. Tuy nhi\u00ean c\u1ea7n l\u01b0u \u00fd, quan s\u00e1t sao b\u0103ng kh\u00f4ng n\u00ean ch\u1ec9 ch\u00fa t\u00e2m v\u00e0o t\u00e2m \u0111i\u1ec3m m\u00e0 ph\u1ea3i \u0111\u01b0a m\u1eaft bao qu\u00e1t c\u1ea3 v\u00f9ng tr\u1eddi xung quanh n\u00f3.<\/div>\n<\/div>\n
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C\u1ef1c \u0111i\u1ec3m (peak) l\u00e0 th\u1eddi \u0111i\u1ec3m m\u00e0 Tr\u00e1i \u0110\u1ea5t \u0111i v\u00e0o v\u00f9ng kh\u00f4ng gian c\u00f3 nhi\u1ec1u \u0111\u00e1\/b\u1ee5i sao ch\u1ed5i nh\u1ea5t (meteoroid swarm) v\u00e0 th\u01b0\u1eddng k\u00e9o d\u00e0i trong 1-2 ti\u1ebfng. Nh\u01b0ng th\u1eddi \u0111i\u1ec3m n\u00e0y kh\u00f4ng h\u1eb3n l\u00e0 th\u1eddi \u0111i\u1ec3m quan s\u00e1t \u0111\u01b0\u1ee3c nhi\u1ec1u sao b\u0103ng nh\u1ea5t \u1edf m\u1ed9t \u0111\u1ecba ph\u01b0\u01a1ng. C\u00f3 nh\u1eefng l\u00fac c\u1ef1c \u0111i\u1ec3m c\u1ee7a m\u1ed9t tr\u1eadn m\u01b0a sao b\u0103ng l\u1ea1i t\u01b0\u01a1ng \u1ee9ng v\u00e0o ban ng\u00e0y t\u1ea1i Vi\u1ec7t Nam, do \u0111\u00f3 ch\u00fang ta kh\u00f4ng th\u1ec3 quan s\u00e1t \u0111\u01b0\u1ee3c c\u00e1c v\u1ec7t sao b\u0103ng v\u00e0o l\u00fac n\u00e0y.<\/div>\n
Do v\u1eady, ngo\u00e0i th\u1eddi gian c\u1ef1c \u0111i\u1ec3m, c\u00e1c nh\u00e0 thi\u00ean v\u0103n c\u00f2n cho d\u1ef1 b\u00e1o v\u1ec1 th\u1eddi gian l\u00e2n c\u1eadn c\u1ef1c \u0111i\u1ec3m v\u1edbi c\u00e1c tr\u1eadn m\u01b0a sao b\u0103ng l\u1edbn, \u0111\u00e2y l\u00e0 th\u1eddi gian c\u00f3 m\u1eadt \u0111\u1ed9 sao b\u0103ng theo l\u00fd thuy\u1ebft r\u1ea5t cao, th\u1eddi gian n\u00e0y th\u01b0\u1eddng k\u00e9o d\u00e0i kho\u1ea3ng m\u1ed9t v\u00e0i ng\u00e0y quanh c\u1ef1c \u0111i\u1ec3m. T\u1ea1i Vi\u1ec7t Nam, c\u00f3 l\u00fac c\u1ef1c \u0111i\u1ec3m r\u01a1i v\u00e0o gi\u1eefa tr\u01b0a, v\u00e0o ban ng\u00e0y th\u00ec l\u00e0 th\u1eddi \u0111i\u1ec3m \u201cl\u01a1 l\u1eedng\u201d<\/div>\n
V\u1eady ch\u1ecdn th\u1eddi \u0111i\u1ec3m n\u00e0o \u0111\u1ec3 quan s\u00e1t. T\u00f9y m\u1ed7i ng\u01b0\u1eddi \u01b0\u1edbc l\u01b0\u1ee3ng v\u00e0 cho \u0111\u00e1nh gi\u00e1 ri\u00eang c\u1ee7a m\u00ecnh nh\u01b0ng v\u1edbi tr\u01b0\u1eddng h\u1ee3p c\u1ef1c \u0111i\u1ec3m “l\u01a1 l\u1eedng” nh\u01b0 th\u1ebf n\u00e0y theo HAAC th\u00ec ta n\u00ean quan s\u00e1t c\u1ea3 hai \u0111\u00eam tr\u01b0\u1edbc v\u00e0 sau c\u1ef1c \u0111i\u1ec3m v\u00ec c\u00f2n m\u1ed9t y\u1ebfu t\u1ed1 th\u1eddi ti\u1ebft l\u00e0 y\u1ebfu t\u1ed1 m\u00e0 kh\u00f4ng th\u1ec3 n\u00e0o d\u1ef1 b\u00e1o tr\u01b0\u1edbc ch\u00ednh x\u00e1c \u0111\u01b0\u1ee3c.<\/div>\n<\/div>\n
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Kh\u00f4ng ai c\u00f3 th\u1ec3 d\u1ef1 b\u00e1o \u0111\u01b0\u1ee3c s\u1ed1 sao b\u0103ng c\u00f3 th\u1ec3 quan s\u00e1t \u0111\u01b0\u1ee3c \u1edf m\u1ed9t \u0111\u1ecba ph\u01b0\u01a1ng v\u00ec n\u00f3 ph\u1ee5 thu\u1ed9c v\u00e0o r\u1ea5t nhi\u1ec1u y\u1ebfu t\u1ed1 trong \u0111\u00f3 c\u00f3 nh\u1eefng y\u1ebfu t\u1ed1 kh\u00f4ng \u0111o\u00e1n tr\u01b0\u1edbc \u0111\u01b0\u1ee3c nh\u01b0 m\u00e2y, m\u01b0a b\u1ea5t ch\u1ee3t.<\/div>\n
Ta b\u1ecf qua m\u1ecdi y\u1ebfu t\u1ed1 th\u1eddi ti\u1ebft th\u00ec gi\u1ea3 s\u1eed m\u1eadt \u0111\u1ed9 sao b\u0103ng trong \u0111\u00e1m m\u00e2y \u0111\u00e1\/b\u1ee5i l\u00e0 \u0111\u1ec1u nhau \u1edf m\u1ecdi v\u1ecb tr\u00ed th\u00ec:<\/div>\n
– Sau n\u1eeda \u0111\u00eam s\u1ebd quan s\u00e1t \u0111\u01b0\u1ee3c nhi\u1ec1u sao b\u0103ng h\u01a1n tr\u01b0\u1edbc \u0111\u00f3. C\u00e0ng v\u1ec1 s\u00e1ng th\u00ec m\u1eadt \u0111\u1ed9 sao b\u0103ng quan s\u00e1t \u0111\u01b0\u1ee3c c\u00e0ng nhi\u1ec1u.<\/div>\n
– Khi t\u00e2m \u0111i\u1ec3m c\u1ee7a m\u01b0a sao b\u0103ng c\u00e0ng l\u00ean cao th\u00ec s\u1ed1 sao b\u0103ng quan s\u00e1t \u0111\u01b0\u1ee3c c\u00e0ng nhi\u1ec1u, l\u00fd t\u01b0\u1edfng nh\u1ea5t l\u00e0 t\u00e2m \u0111i\u1ec3m l\u00ean \u0111\u1ebfn \u0111i\u1ec3m cao nh\u1ea5t tr\u00ean b\u1ea7u tr\u1eddi.<\/div>\n
– \u00c1nh tr\u0103ng c\u00e0ng s\u00e1ng th\u00ec s\u1ed1 sao b\u0103ng th\u1ea5y \u0111\u01b0\u1ee3c c\u00e0ng gi\u1ea3m, v\u00ec \u00e1nh tr\u0103ng qu\u00e1 s\u00e1ng l\u1ea5n \u00e1t lu\u00f4n c\u00e1c v\u1ec7t sao b\u0103ng.<\/div>\n<\/div>\n
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Do v\u1eady<\/div>\n
, \u0111i\u1ec1u ki\u1ec7n l\u00fd t\u01b0\u1edfng c\u00f3 m\u1eadt \u0111\u1ed9 sao b\u0103ng quan s\u00e1t \u0111\u01b0\u1ee3c l\u1edbn nh\u1ea5t \u1edf m\u1ed9t \u0111\u1ecba ph\u01b0\u01a1ng l\u00e0:<\/div>\n
– Kh\u00f4ng tr\u0103ng (New Moon);<\/div>\n
– C\u1ef1c \u0111i\u1ec3m di\u1ec5n ra khi t\u00e2m \u0111i\u1ec3m l\u00ean \u0111\u1ec9nh \u0111\u1ea7u v\u00e0 di\u1ec5n ra v\u00e0o sau n\u1eeda \u0111\u00eam (\u0111\u1eb7c bi\u1ec7t l\u00e0 sau 2h s\u00e1ng);<\/div>\n
C\u1ef1c \u0111i\u1ec3m theo d\u1ef1 b\u00e1o ch\u1ec9 l\u00e0 th\u00f4ng tin tham kh\u1ea3o quan tr\u1ecdng b\u00ean c\u1ea1nh c\u00e1c y\u1ebfu t\u1ed1 kh\u00e1c nh\u01b0 \u1edf tr\u00ean quy\u1ebft \u0111\u1ecbnh \u0111\u1ebfn s\u1ed1 sao b\u0103ng m\u00e0 ta c\u00f3 th\u1ec3 quan s\u00e1t \u0111\u01b0\u1ee3c. C\u1ef1c \u0111i\u1ec3m kh\u00f4ng ph\u1ea3i l\u00e0 th\u1eddi \u0111i\u1ec3m m\u00e0 \u1edf m\u1ed9t \u0111\u1ecba ph\u01b0\u01a1ng c\u00f3 th\u1ec3 quan s\u00e1t \u0111\u01b0\u1ee3c nhi\u1ec1u sao b\u0103ng nh\u1ea5t.<\/div>\n
Ch\u00fang ta n\u00ean hi\u1ec3u: C\u1ef1c \u0111i\u1ec3m l\u00e0 th\u1eddi gian Tr\u00e1i \u0110\u1ea5t \u0111i v\u00e0o v\u00f9ng c\u00f3 nhi\u1ec1u b\u1ee5i sao ch\u1ed5i nh\u1ea5t, c\u00f2n c\u00f3 quan s\u00e1t \u0111\u01b0\u1ee3c nhi\u1ec1u hay \u00edt sao b\u0103ng th\u00ec c\u00f2n t\u00f9y v\u00e0o v\u1ecb tr\u00ed \u0111\u1ecba l\u00fd \u0111\u1ec3 bi\u1ebft l\u00fac \u0111\u00f3 t\u00e2m \u0111i\u1ec3m m\u1ecdc khi n\u00e0o v\u00e0 c\u00e1c y\u1ebfu t\u1ed1 kh\u00e1c nh\u01b0 th\u1eddi ti\u1ebft, \u00e1nh tr\u0103ng.<\/div>\n<\/div>\n
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4. V\u00ec sao l\u1ea1i quan s\u00e1t nhi\u1ec1u sao b\u0103ng h\u01a1n v\u00e0o sau n\u1eeda \u0111\u00eam?<\/div>\n
Theo h\u00ecnh minh h\u1ecda, sau th\u1eddi \u0111i\u1ec3m n\u1eeda \u0111\u00eam (midnight), n\u1eeda b\u00ean tr\u00e1i Tr\u00e1i \u0110\u1ea5t \u1edf ban \u0111\u00eam (quan s\u00e1t \u0111\u01b0\u1ee3c v\u1ec7t sao b\u0103ng) s\u1ebd \u1edf v\u1ecb tr\u00ed h\u01b0\u1edbng tr\u1ef1c ti\u1ebfp v\u1ec1 ph\u00eda d\u1ea3i \u0111\u00e1\/b\u1ee5i trong kh\u00f4ng gian theo h\u01b0\u1edbng di chuy\u1ec3n c\u1ee7a h\u00e0nh tinh ch\u00fang ta tr\u00ean qu\u1ef9 \u0111\u1ea1o, do \u0111\u00f3 sau n\u1eeda \u0111\u00eam l\u00e0 th\u1eddi \u0111i\u1ec3m ch\u00fang ta c\u00f3 th\u1ec3 quan s\u00e1t \u0111\u01b0\u1ee3c nhi\u1ec1u v\u1ec7t sao b\u0103ng h\u01a1n tr\u01b0\u1edbc \u0111\u00f3.<\/div>\n
5. C\u00e1c nh\u00e0 thi\u00ean v\u0103n d\u1ef1 b\u00e1o c\u1ef1c \u0111i\u1ec3m m\u01b0a sao b\u0103ng nh\u01b0 th\u1ebf n\u00e0o?<\/div>\n
Kh\u00f4ng th\u1ec3 n\u00e0o m\u00e0 d\u1ef1 b\u00e1o ch\u00ednh x\u00e1c \u0111\u01b0\u1ee3c s\u1ed1 l\u01b0\u1ee3ng \u0111\u00e1\/b\u1ee5i do c\u00e1c sao ch\u1ed5i\/ti\u1ec3u h\u00e0nh \u0111\u1ec3 l\u1ea1i c\u1ea3. Vi\u1ec7c t\u00ednh to\u00e1n c\u00f3 l\u1ebd r\u1ea5t ph\u1ee9c t\u1ea1p ph\u1ea3i d\u1ef1a tr\u00ean c\u00e1c m\u00f4 h\u00ecnh m\u00e1y t\u00ednh. D\u1ea3i \u0111\u00e1\/b\u1ee5i c\u0169ng chuy\u1ec3n \u0111\u1ed9ng xung quanh M\u1eb7t Tr\u1eddi theo m\u1ed9t qu\u0129 \u0111\u1ea1o nh\u1ea5t \u0111\u1ecbnh. Trong c\u00e1c d\u1ea3i (\u0111\u00e1m) \u0111\u00e1\/b\u1ee5i n\u00e0y th\u00ec l\u1ea1i c\u00f3 t\u1eebng “c\u1ee5m” \u0111\u00e1\/b\u1ee5i ch\u1ee9 kh\u00f4ng ph\u1ea3i l\u00e0 m\u1eadt \u0111\u1ed9 ph\u00e2n b\u1ed1 lu\u00f4n \u0111\u1ec1u nhau.<\/div>\n
C\u00f3 l\u1ebd c\u00e1c nh\u00e0 thi\u00ean v\u0103n ch\u1ec9 c\u00f3 th\u1ec3 t\u00ednh to\u00e1n \u0111\u01b0\u1ee3c l\u00e0 th\u1eddi gian qu\u0129 \u0111\u1ea1o Tr\u00e1i \u0110\u1ea5t c\u1eaft qua qu\u0129 \u0111\u1ea1o d\u1ea3i \u0111\u00e1\/b\u1ee5i v\u00e0o th\u1eddi \u0111i\u1ec3m n\u00e0o, v\u00e0 th\u1eddi gian g\u1eb7p “c\u1ee5m” b\u1ee5i c\u00f3 m\u1eadt \u0111\u1ed9 cao nh\u1ea5t trong n\u0103m l\u00e0 th\u1eddi gian di\u1ec5n ra c\u1ef1c \u0111i\u1ec3m c\u00f3 th\u1ec3 quan s\u00e1t \u0111\u01b0\u1ee3c nhi\u1ec1u sao b\u0103ng nh\u1ea5t. S\u1ed1 ng\u00e0y m\u00e0 ta c\u00f3 th\u1ec3 quan s\u00e1t \u0111\u01b0\u1ee3c c\u1ee7a m\u1ed9t \u0111\u1ee3t sao b\u0103ng l\u00e0 ph\u1ee5 thu\u1ed9c v\u00e0o \u0111\u1ed9 r\u1ed9ng c\u1ee7a d\u1ea3i \u0111\u00e1\/b\u1ee5i tr\u00ean qu\u0129 \u0111\u1ea1o c\u1ee7a n\u00f3 m\u00e0 Tr\u00e1i \u0110\u1ea5t c\u1eaft qua.<\/div>\n
Vi\u1ec7c \u0111\u00e1nh gi\u00e1 d\u1ef1 b\u00e1o s\u1ed1 v\u1ec7t sao b\u0103ng c\u1ef1c \u0111\u1ea1i\/h c\u00f3 l\u1ebd l\u00e0 qua th\u1ed1ng k\u00ea c\u1ee7a t\u1eebng n\u0103m. V\u00ed d\u1ee5 n\u1ebfu g\u1eb7p \u0111\u01b0\u1ee3c c\u1ee5m \u0111\u00e1\/b\u1ee5i A th\u00ec th\u00f4ng th\u01b0\u1eddng th\u1ea5y \u0111\u01b0\u1ee3c bao nhi\u00eau v\u1ec7t sao b\u0103ng, g\u1eb7p c\u1ee5m \u0111\u00e1\/b\u1ee5i B th\u00ec bao nhi\u00eau v\u1ec7t sao b\u0103ng…, v\u00e0 t\u1eeb \u0111\u00f3 c\u00e1c nh\u00e0 khoa h\u1ecdc cho ra con s\u1ed1 d\u1ef1 b\u00e1o c\u00f3 th\u1ec3 th\u1ea5y \u0111\u01b0\u1ee3c.<\/div>\n<\/div>\n
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V\u00ed d\u1ee5 nh\u01b0 qu\u0129 \u0111\u1ea1o Tr\u00e1i \u0110\u1ea5t c\u1eaft qu\u0129 \u0111\u1ea1o \u0111\u00e1m m\u00e2y b\u1ee5i c\u1ee7a m\u01b0a sao b\u0103ng Leonids v\u00e0o n\u0103m 2000:<\/div>\n
\u1ea2nh c\u1ee7a NASA cho Leonids n\u0103m 2007<\/div>\n
Ta c\u00f3 th\u1ec3 th\u1ea5y v\u1ecb tr\u00ed c\u1eaft c\u1ee7a qu\u0129 \u0111\u1ea1o Tr\u00e1i \u0110\u1ea5t v\u1edbi qu\u0129 \u0111\u1ea1o d\u1ea3i \u0111\u00e1\/b\u1ee5i l\u00e0 kh\u00f4ng c\u1ed1 \u0111\u1ecbnh theo t\u1eebng n\u0103m. Vi\u1ec7c d\u1ef1 b\u00e1o s\u1ed1 l\u01b0\u1ee3ng v\u1ec7t sao b\u0103ng c\u00f3 th\u1ec3 th\u1ea5y \u0111\u01b0\u1ee3c ch\u1ec9 l\u00e0 t\u01b0\u01a1ng \u0111\u1ed1i. \u0110\u1ed1i v\u1edbi tr\u1eadn m\u01b0a sao b\u0103ng Geminids hi\u1ec7n nay m\u1eadt \u0111\u1ed9 b\u1ee5i ph\u00e2n b\u1ed1 kh\u00e1 \u0111\u1ed3ng \u0111\u1ec1u n\u00ean s\u1ed1 l\u01b0\u1ee3ng d\u1ef1 b\u00e1o t\u01b0\u01a1ng \u0111\u1ed1i ch\u00ednh x\u00e1c. C\u00f2n v\u1edbi Leonids th\u00ec c\u00e1c n\u0103m g\u1ea7n \u0111\u00e2y khi Leonids \u0111\u00e3 suy y\u1ebfu th\u00ec d\u1ef1 b\u00e1o kh\u00e1 kh\u00f3 kh\u0103n tr\u00ean IMO cho d\u1ef1 b\u00e1o th\u01b0\u1eddng l\u00e0 t\u1eeb kho\u1ea3ng 20 v\u1ec7t \u0111\u1ebfn “b\u00e3o” sao b\u0103ng\/h;<\/div>\n<\/div>\n
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6. Th\u1ed1ng k\u00ea s\u1ed1 v\u1ec7t sao b\u0103ng\/h \u1edf c\u00e1c trang nh\u01b0 IMO \u0111\u01b0\u1ee3c t\u00ednh to\u00e1n nh\u01b0 th\u1ebf n\u00e0o? \u0110\u00f3 c\u00f3 ph\u1ea3i l\u00e0 con s\u1ed1 m\u00e0 th\u1ef1c t\u1ebf ch\u00fang ta xem \u0111\u01b0\u1ee3c?<\/div>\n<\/div>\n
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Tr\u01b0\u1edbc m\u1ed7i tr\u1eadn m\u01b0a sao b\u0103ng th\u01b0\u1eddng c\u00f3 c\u00e1c d\u1ef1 b\u00e1o s\u1ed1 v\u1ec7t sao b\u0103ng c\u00f3 th\u1ec3 quan s\u00e1t \u0111\u01b0\u1ee3c theo gi\u1edd t\u1ea1i th\u1eddi \u0111i\u1ec3m c\u1ef1c \u0111i\u1ec3m. S\u1ed1 v\u1ec7t sao b\u0103ng n\u00e0y th\u01b0\u1eddng \u0111\u01b0\u1ee3c d\u1ef1 b\u00e1o theo con s\u1ed1 th\u1ed1ng k\u00ea c\u00e1c n\u0103m tr\u01b0\u1edbc t\u1eeb c\u00e1c b\u00e1o c\u00e1o c\u1ee7a c\u00e1c n\u01a1i quan s\u00e1t kh\u00e1c nhau.<\/div>\n
Hi\u1ec7n nay, International Meteor Organization (IMO) – Hi\u1ec7p H\u1ed9i M\u01b0a Sao B\u0103ng Qu\u1ed1c T\u1ebf, tuy l\u00e0 m\u1ed9t t\u1ed5 ch\u1ee9c nghi\u1ec7p d\u01b0 nh\u01b0ng c\u00f3 th\u1ec3 xem nh\u01b0 l\u00e0 t\u1ed5 ch\u1ee9c uy t\u00edn nh\u1ea5t tr\u00ean th\u1ebf gi\u1edbi v\u1ec1 c\u00e1c d\u1ef1 b\u00e1o v\u00e0 th\u1ed1ng k\u00ea m\u1eadt \u0111\u1ed9 sao b\u0103ng h\u00e0ng n\u0103m. Trong m\u1ed7i \u0111\u1ee3t m\u01b0a sao b\u0103ng IMO k\u00eau g\u1ecdi ng\u01b0\u1eddi quan s\u00e1t \u1edf kh\u1eafp c\u00e1c n\u01a1i tr\u00ean th\u1ebf gi\u1edbi g\u1eedi b\u00e1o c\u00e1o v\u1ec1 s\u1ed1 sao b\u0103ng m\u00e0 h\u1ecd quan s\u00e1t \u0111\u01b0\u1ee3c \u0111\u1ec3 IMO t\u1ed5ng h\u1ee3p, v\u00e0 \u0111\u00e2y c\u0169ng l\u00e0 s\u1ed1 li\u1ec7u gi\u00fap cho c\u00e1c nh\u00e0 thi\u00ean v\u0103n h\u1ecdc c\u1ed9ng t\u00e1c v\u1edbi IMO cho d\u1ef1 b\u00e1o v\u1ec1 m\u1eadt \u0111\u1ed9 sao b\u0103ng \u1edf c\u00e1c n\u0103m sau.<\/div>\n<\/div>\n
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7. Ch\u00fang ta hay nghe thu\u1eadt ng\u1eef t\u1ea7n su\u1ea5t ZHR v\u1ec7t sao b\u0103ng\/gi\u1edd c\u1ee7a m\u1ed7i tr\u1eadn m\u01b0a sao b\u0103ng, n\u00f3 l\u00e0 g\u00ec?<\/div>\n
ZHR (Zenithal Hourly Rate)<\/div>\n
C\u00e1c th\u1ed1ng k\u00ea v\u1ec1 m\u1eadt \u0111\u1ed9 v\u00e0 d\u1ef1 b\u00e1o c\u1ee7a IMO \u0111\u1ec1u quy v\u1ec1 d\u1ea1ng ZHR (Zenithal Hourly Rate) – t\u1ea7n su\u1ea5t v\u1ec7t sao b\u0103ng\/h khi t\u00e2m \u0111i\u1ec3m sao b\u0103ng \u1edf thi\u00ean \u0111\u1ec9nh trong \u0111i\u1ec1u ki\u1ec7n quan s\u00e1t t\u1ed1i \u01b0u (v\u1edbi b\u1ea7u tr\u1eddi th\u1eadt t\u1ed1i v\u00e0 trong\/gi\u1edbi h\u1ea1n c\u1ea5p sao c\u00f3 th\u1ec3 nh\u00ecn th\u1ea5y \u0111\u01b0\u1ee3c l\u00e0 +6.5).<\/div>\n
T\u1ea7n su\u1ea5t sao b\u0103ng n\u00e0y l\u00e0 con s\u1ed1 l\u00fd t\u01b0\u1edfng nh\u1ea5t c\u00f3 th\u1ec3 quan s\u00e1t \u0111\u01b0\u1ee3c. Th\u1ef1c t\u1ebf kh\u00f4ng th\u1ec3 d\u1ef1 b\u00e1o ch\u00ednh x\u00e1c cho t\u1eebng v\u00f9ng v\u00ec \u0111i\u1ec1u ki\u1ec7n th\u1eddi ti\u1ebft c\u0169ng nh\u01b0 v\u1ecb tr\u00ed t\u00e2m \u0111i\u1ec3m c\u1ee7a sao b\u0103ng khi di\u1ec5n ra c\u1ef1c \u0111i\u1ec3m l\u00e0 kh\u00e1c nhau cho m\u1ed7i n\u01a1i.<\/div>\n
ZHR \u0111\u01b0\u1ee3c t\u00ednh to\u00e1n theo c\u00f4ng th\u1ee9c sau:<\/div>\n<\/div>\n
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ZHR = (HR*F* r^(6.5-lm))\/sin(hR)<\/div>\n<\/div>\n
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V\u1edbi:<\/div>\n<\/div>\n
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HR: L\u00e0 t\u1ea7n su\u1ea5t v\u1ec7t sao b\u0103ng\/h quan s\u00e1t \u0111\u01b0\u1ee3c th\u1eadt s\u1ef1 c\u1ee7a c\u00e1c b\u00e1o c\u00e1o vi\u00ean. HR= N\/Tef, trong \u0111\u00f3 N l\u00e0 s\u1ed1 l\u01b0\u1ee3ng sao b\u0103ng quan s\u00e1t \u0111\u01b0\u1ee3c, Teff l\u00e0 th\u1eddi gian quan s\u00e1t hi\u1ec7u qu\u1ea3 c\u1ee7a b\u00e1o c\u00e1o vi\u00ean.<\/div>\n
V\u00ed d\u1ee5: m\u1ed9t ng\u01b0\u1eddi quan s\u00e1t \u0111\u1ebfm \u0111\u01b0\u1ee3c 12 sao b\u0103ng trong 15 ph\u00fat, th\u00ec t\u1ea7n su\u1ea5t sao b\u0103ng\/h l\u00e0 48 (12 chia cho 0.25 gi\u1edd)<\/div>\n<\/div>\n
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F h\u1ec7 s\u1ed1 hi\u1ec7u ch\u1ec9nh v\u00f9ng quan s\u00e1t \u0111\u01b0\u1ee3c, k l\u00e0 % v\u00f9ng nh\u00ecn c\u1ee7a ng\u01b0\u1eddi quan s\u00e1t b\u1ecb che khu\u1ea5t (v\u00ed d\u1ee5 b\u1edfi m\u00e2y), v\u00e0 F = 1\/(1-k)<\/div>\n
V\u00ed d\u1ee5: n\u1ebfu 20% v\u00f9ng nh\u00ecn c\u1ee7a ng\u01b0\u1eddi quan s\u00e1t b\u1ecb m\u00e2y che, h\u1ec7 s\u1ed1 k l\u00e0 0.2 v\u00e0 F s\u1ebd l\u00e0 1.25. N\u1ebfu kh\u00f4ng b\u1ecb che ch\u1eafn c\u00f3 th\u1ec3 ng\u01b0\u1eddi quan s\u00e1t s\u1ebd th\u1ea5y nhi\u1ec1u h\u01a1n s\u1ed1 sao b\u0103ng m\u00e0 h\u1ecd \u0111\u1ebfm \u0111\u01b0\u1ee3c l\u00e0 25% n\u1eefa. V\u00ec th\u1ebf ch\u00fang ta s\u1ebd nh\u00e2n cho t\u1ec9 l\u1ec7 F=1.25<\/div>\n<\/div>\n
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– r^(6.5 \u2013 lm)<\/div>\n<\/div>\n
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\u0110\u00e2y l\u00e0 h\u1ec7 s\u1ed1 hi\u1ec7u ch\u1ec9nh \u0111\u1ed9 s\u00e1ng c\u1ee7a sao b\u0103ng c\u00f3 th\u1ec3 quan s\u00e1t \u0111\u01b0\u1ee3c. \u1ede 2 n\u01a1i kh\u00e1c nhau: n\u1ebfu b\u1ea7u tr\u1eddi \u1edf \u0111\u1ecba ph\u01b0\u01a1ng A trong h\u01a1n c\u00f3 th\u1ec3 quan s\u00e1t \u0111\u01b0\u1ee3c c\u00e1c sao b\u0103ng c\u00f3 c\u1ea5p sao m\u1edd h\u01a1n \u1edf \u0111\u1ecba ph\u01b0\u01a1ng B l\u00e0 +1 th\u00ec s\u1ed1 v\u1ec7t sao b\u0103ng \u0111\u00e1ng l\u1ebd c\u00f3 th\u1ec3 quan s\u00e1t \u0111\u01b0\u1ee3c \u1edf B n\u1ebfu tr\u1eddi c\u0169ng trong nh\u01b0 A = s\u1ed1 sao b\u0103ng \u0111\u1ebfm \u0111\u01b0\u1ee3c \u1edf B nh\u00e2n th\u00eam cho t\u1ec9 l\u1ec7 r^1 n\u1eefa. \u1ede \u0111\u00e2y ta gi\u1ea3 s\u1eed \u0111i\u1ec1u ki\u1ec7n l\u00fd t\u01b0\u1edfng l\u00e0 n\u01a1i quan s\u00e1t c\u00f3 th\u1ec3 th\u1ea5y sao c\u00f3 \u0111\u1ed9 s\u00e1ng +6,5; n\u00ean t\u1eeb c\u00e1c s\u1ed1 sao b\u0103ng th\u1eadt s\u1ef1 ch\u00fang ta quan s\u00e1t \u0111\u01b0\u1ee3c, ta s\u1ebd hi\u1ec7u ch\u1ec9nh l\u1ea1i \u0111\u1ed9 trong c\u1ee7a b\u1ea7u tr\u1eddi \u0111\u1ec3 t\u00ednh ra c\u00e1c sao b\u0103ng m\u00e0 \u0111\u00e1ng ra c\u00f3 th\u1ec3 th\u1ea5y \u0111\u01b0\u1ee3c n\u1ebfu tr\u1eddi th\u1eadt trong.<\/div>\n
– r: cho b\u1edfi th\u1ed1ng k\u00ea \u0111\u1ed9 s\u00e1ng c\u1ee7a t\u1eebng sao b\u0103ng m\u00e0 ta quan s\u00e1t \u0111\u01b0\u1ee3c, IMO th\u01b0\u1eddng cho s\u1eb5n h\u1ec7 s\u1ed1 r \u0111\u1ed1i v\u1edbi m\u1ed7i tr\u1eadn m\u01b0a sao b\u0103ng d\u1ef1a tr\u00ean c\u00e1c b\u00e1o c\u00e1o h\u1eb1ng n\u0103m. Geminids c\u00f3 r l\u00e0 = 2.6<\/div>\n
N\u1ebfu \u1edf v\u00f9ng ven th\u00e0nh ph\u1ed1 H\u1ed3 Ch\u00ed Minh nh\u01b0 Th\u1ee7 \u0110\u1ee9c, ch\u00fang ta ch\u1ec9 quan s\u00e1t \u0111\u01b0\u1ee3c c\u00e1c v\u1ec7t sao b\u0103ng m\u1edd nh\u1ea5t c\u00f3 \u0111\u1ed9 s\u00e1ng l\u00e0 +5.5, nh\u01b0ng \u1edf B\u1ea3o L\u1ed9c tr\u1eddi trong h\u01a1n n\u00ean c\u00f3 th\u1ec3 th\u1ea5y c\u00e1c v\u1ec7t sao b\u0103ng m\u1edd c\u00f3 \u0111\u1ed9 s\u00e1ng \u0111\u1ebfn c\u1ea5p +6.5. Ng\u01b0\u1eddi quan s\u00e1t \u1edf Th\u1ee7 \u0110\u1ee9c n\u1ebfu \u0111\u1ebfm \u0111\u01b0\u1ee3c 50 v\u1ec7t sao b\u0103ng, c\u00f3 th\u1ec3 ng\u01b0\u1eddi \u1edf B\u1ea3o L\u1ed9c th\u1ea5y \u0111\u01b0\u1ee3c g\u1ea5p \u0111\u00f4i l\u00e0 130 v\u1ec7t sao b\u0103ng = 50 x r ^(6.5-5.5) v\u1edbi r =2.6.<\/div>\n<\/div>\n
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\u01af\u1edbc l\u01b0\u1ee3ng gi\u1edbi h\u1ea1n \u0111\u1ed9 s\u00e1ng c\u1ee7a v\u1ec7t sao b\u0103ng m\u00e0 b\u1ea7u tr\u1eddi m\u00e0 m\u00ecnh quan s\u00e1t \u0111\u01b0\u1ee3c nh\u01b0 th\u1ebf n\u00e0o? Ta c\u00f3 th\u1ec3 c\u0103n c\u1ee9 v\u00e0o \u0111\u1ed9 s\u00e1ng c\u1ee7a c\u00e1c sao tr\u00ean b\u1ea7u tr\u1eddi, n\u1ebfu ch\u1ec9 th\u1ea5y \u0111\u01b0\u1ee3c c\u00e1c sao t\u1ea7m +2 nh\u01b0 \u1edf trung t\u00e2m th\u00e0nh ph\u1ed1 th\u00ec \u0111\u1eebng k\u1ef3 v\u1ecdng v\u1ec1 m\u1ed9t \u0111\u00eam quan s\u00e1t m\u01b0a sao b\u0103ng ho\u00e0nh tr\u00e1ng nh\u01b0 \u1edf B\u1ea3o L\u1ed9c.<\/div>\n
Ta c\u0169ng th\u1ea5y \u0111\u01b0\u1ee3c s\u1eed \u1ea3nh h\u01b0\u1edfng c\u1ee7a \u00e1nh tr\u0103ng, \u00e1nh \u0111\u00e8n v\u1edbi quan s\u00e1t sao b\u0103ng nh\u01b0 th\u1ebf n\u00e0o.<\/div>\n<\/div>\n
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– Sin(hR) : H\u1ec7 s\u1ed1 hi\u1ec7u ch\u1ec9nh \u0111\u1ed9 cao c\u1ee7a t\u00e2m \u0111i\u1ec3m sao b\u0103ng (radiant). hR l\u00e0 \u0111\u1ed9 cao c\u1ee7a t\u00e2m \u0111i\u1ec3m c\u00e1ch ch\u00e2n tr\u1eddi.<\/div>\n
S\u1ed1 v\u1ec7t sao b\u0103ng quan s\u00e1t \u0111\u01b0\u1ee3c s\u1ebd c\u00f3 t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi \u0111\u1ed9 cao c\u1ee7a t\u00e2m \u0111i\u1ec3m.<\/div>\n
V\u00ed d\u1ee5: n\u1ebfu t\u00e2m \u0111i\u1ec3m cao trung b\u00ecnh kho\u1ea3ng 30 \u0111\u1ed9 trong th\u1eddi \u0111i\u1ec3m quan s\u00e1t sao b\u0103ng (tr\u1eadn Geminds l\u00e0 t\u1ea7m 9-10h t\u1ed1i), ta c\u00f3 th\u1ec3 chia t\u1ea7n su\u1ea5t sao b\u0103ng th\u1ea5y \u0111\u01b0\u1ee3c cho 0.5 (sin 30\u0111\u1ed9) \u0111\u1ec3 \u01b0\u1edbc l\u01b0\u1ee3ng s\u1ed1 sao b\u0103ng m\u00e0 b\u1ea1n n\u01b0\u1edbc ngo\u00e0i \u1edf n\u01a1i m\u00e0 ch\u00f2m Geminids \u0111\u00e3 l\u00ean cao \u0111\u1ebfn thi\u00ean \u0111\u1ec9nh c\u00f3 th\u1ec3 th\u1ea5y \u0111\u01b0\u1ee3c c\u00f9ng l\u00fac \u0111\u00f3 v\u1edbi ta.<\/div>\n
Ng\u01b0\u1ee3c l\u1ea1i v\u00ed d\u1ee5 tr\u00ean IMO cho th\u1eddi gian c\u1ef1c \u0111i\u1ec3m c\u1ee7a m\u01b0a sao b\u0103ng Geminids l\u00e0 kho\u1ea3ng 10:00PM \u1edf Vi\u1ec7t Nam v\u1edbi ZHR l\u00e0 120 v\u1ec7t sao b\u0103ng\/h khi c\u1ef1c \u0111i\u1ec3m. Nh\u01b0ng r\u1ee7i thay l\u00fac \u0111\u00f3 t\u00e2m \u0111i\u1ec3m sao b\u0103ng \u1edf n\u01b0\u1edbc ta ch\u1ec9 cao kho\u1ea3ng 30 \u0111\u1ed9 th\u00ec s\u1ed1 v\u1ec7t sao b\u0103ng d\u1ef1 b\u00e1o quan s\u00e1t \u0111\u01b0\u1ee3c \u1edf n\u01b0\u1edbc ta v\u1edbi \u0111i\u1ec1u ki\u1ec7n th\u1eddi ti\u1ebft th\u1eadt l\u00fd t\u01b0\u1edfng ngay l\u00fac c\u1ef1c \u0111i\u1ec3m 10:00PM t\u1ed1i ch\u1ec9 c\u00f2n l\u00e0 120×0.5 = 60 v\u1ec7t sao b\u0103ng\/h.<\/div>\n
\"\"<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

HAAC – C\u00e2u l\u1ea1c b\u1ed9 Thi\u00ean v\u0103n nghi\u1ec7p d\u01b0 TP.HCM 22 November at 13:14\u00a0 \u00b7 Ch\u1ee7 \u0111\u1ec1 c\u1ee7a tr\u1ea1i thi\u00ean v\u0103n th\u00e1ng 12 t\u1edbi l\u00e0 \u201cM\u01b0a sao b\u0103ng\u201d, n\u0103m nay t\u00e2m \u0111i\u1ec3m c\u1ee7a tr\u1eadn m\u01b0a sao b\u0103ng Geminids \u0111\u00e1ng ch\u00fa \u00fd nh\u1ea5t n\u0103m n\u00e0y kho\u1ea3ng 12-13\/12 tr\u00f9ng th\u1eddi \u0111i\u1ec3m kh\u00f4ng tr\u0103ng \u201c New Moon\u201d, r\u1ea5t […]\n","protected":false},"author":1,"featured_media":1260,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[37,1,35],"tags":[],"_links":{"self":[{"href":"https:\/\/vietweather.com\/index.php\/wp-json\/wp\/v2\/posts\/1255"}],"collection":[{"href":"https:\/\/vietweather.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vietweather.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vietweather.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/vietweather.com\/index.php\/wp-json\/wp\/v2\/comments?post=1255"}],"version-history":[{"count":1,"href":"https:\/\/vietweather.com\/index.php\/wp-json\/wp\/v2\/posts\/1255\/revisions"}],"predecessor-version":[{"id":1263,"href":"https:\/\/vietweather.com\/index.php\/wp-json\/wp\/v2\/posts\/1255\/revisions\/1263"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/vietweather.com\/index.php\/wp-json\/wp\/v2\/media\/1260"}],"wp:attachment":[{"href":"https:\/\/vietweather.com\/index.php\/wp-json\/wp\/v2\/media?parent=1255"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vietweather.com\/index.php\/wp-json\/wp\/v2\/categories?post=1255"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vietweather.com\/index.php\/wp-json\/wp\/v2\/tags?post=1255"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}