{"id":3620,"date":"2021-08-01T15:53:57","date_gmt":"2021-08-01T13:53:57","guid":{"rendered":"http:\/\/robinfo.oma.be\/?p=3620"},"modified":"2025-02-24T16:46:33","modified_gmt":"2025-02-24T15:46:33","slug":"aout-2021-dans-le-ciel-d","status":"publish","type":"post","link":"https:\/\/robinfo.oma.be\/fr\/aout-2021-dans-le-ciel-d\/","title":{"rendered":"Ao\u00fbt 2021 (Dans le ciel d\u2019)"},"content":{"rendered":"

AVIS IMPORTANT\u00a0: Pour obtenir l\u2019heure officielle, ajouter DEUX heures aux heures indiqu\u00e9es ci-dessous (en Temps Universel UT pour Uccle)<\/i><\/span><\/span><\/p>\n

Ph\u00e9nom\u00e8nes c\u00e9lestes int\u00e9ressants<\/h3>\n

1<\/b><\/span><\/span><\/span> La Lune<\/span><\/span><\/span> <\/b>\u00e0 2\u00b0 au sud d\u2019Uranus (+5,8) \u00e0 0 h<\/span><\/span><\/span><\/p>\n

Mercure en conjonction sup\u00e9rieure avec le Soleil \u2013 d\u00e8s lors non observable \u2013 \u00e0 14 h <\/span><\/span><\/span><\/p>\n

2 <\/b><\/span><\/span><\/span>Saturne (+0,2) en opposition avec le Soleil \u2013 d\u00e8s lors observable pendant toute la dur\u00e9e de la nuit \u2013 \u00e0 6 h <\/span><\/span><\/span><\/p>\n

La Lune \u00e0 l\u2019apog\u00e9e <\/span><\/span><\/span>(\u00e0 404 412 km de la Terre \u2013 Diam\u00e8tre apparent\u00a0: 29\u201934\u2019\u2019) <\/span><\/span><\/span>\u00e0 8 h<\/span><\/span><\/span><\/p>\n

3<\/b><\/span><\/span><\/span> La Lune \u00e0 6\u00b0 au nord de l\u2019\u00e9toile Ald\u00e9baran [Alpha Tau (+0,9)] \u00e0 6 h<\/span><\/span><\/span><\/p>\n

4<\/b><\/span><\/span><\/span> Du lever de Jupiter (-2,8) \u00e0 19 h 56 m au 5 ao\u00fbt \u00e0 3 h 36 m (d\u00e9but du cr\u00e9puscule civil), <\/span><\/span><\/span>huit<\/b><\/i><\/span><\/span><\/span> ph\u00e9nom\u00e8nes int\u00e9ressants \u00e0 observer dans les mouvements des quatre principaux satellites de la plan\u00e8te, \u00e0 savoir successivement\u00a0: \u00e0 20 h 41 m, d\u00e9but d\u2019\u00e9clipse de J III (Ganym\u00e8de) dans l\u2019ombre de la plan\u00e8te\u00a0; \u00e0 23 h 25 m, d\u00e9but d\u2019un passage de l\u2019ombre (immersion) de J II (Europa) sur la plan\u00e8te\u00a0; \u00e0 0 h 11 m, d\u00e9but d\u2019un passage de J II (Europa) devant le disque de la plan\u00e8te\u00a0; \u00e0 0 h 47,5 m, d\u00e9but d\u2019une \u00e9clipse de J I (Io) dans l\u2019ombre de la plan\u00e8te\u00a0; \u00e0 1 h 50 m, r\u00e9apparition en fin d\u2019occultation de J III (Ganym\u00e8de) par le disque de la plan\u00e8te\u00a0; \u00e0 2 h 15 m, fin d\u2019un passage de l\u2019ombre (\u00e9mersion) de J II (Europa) sur Jupiter\u00a0; \u00e0 2 h 59 m, fin d\u2019un passage de J II (Europa) devant Jupiter\u00a0; et \u00e0 3 h 27 m, r\u00e9apparition en fin d\u2019occultation de J I (Io) par le disque de Jupiter. D\u00e8s lors, de 0 h 47 m \u00e0 1 h 50 m, J\u00a0IV (Callisto) seul satellite visible de Jupiter.<\/span><\/span><\/span><\/p>\n

5 <\/b><\/span><\/span><\/span>La petite plan\u00e8te (3) Juno (+10,7) stationnaire<\/span><\/span><\/span><\/p>\n

8<\/b><\/span><\/span><\/span> Nouvelle Lune <\/b><\/span><\/span><\/span>\u00e0 13 h 50 m<\/span><\/span><\/span><\/p>\n

10 <\/b><\/span><\/span><\/span>Premier jour (1 Mouharram) de l\u2019ann\u00e9e 1443, <\/span><\/span><\/span>commune<\/i><\/span><\/span><\/span> (354 jours), <\/i><\/span><\/span><\/span>du calendrier musulman<\/span><\/span><\/span><\/p>\n

12<\/b><\/span><\/span><\/span> D\u00e9but d\u2019une \u00e9clipse (disparition) de J III (Ganym\u00e8de) dans l\u2019ombre de Jupiter (-2,9) \u00e0 0 h 41,4 m, suivie \u00e0 1 h 59 m d\u2019un d\u00e9but de passage de l\u2019ombre de J II (Europa) sur la plan\u00e8te, puis \u00e0 2 h 24 m d\u2019un d\u00e9but de passage de J II (Europa) devant le disque de Jupiter, et enfin \u00e0 2 h 41,6 m d\u2019un d\u00e9but d\u2019une \u00e9clipse de J I (Io) dans l\u2019ombre de la plan\u00e8te\u00a0: d\u00e8s lors, \u00e0 partir de ce moment et jusqu\u2019au lever du jour, J IV (Callisto) seul satellite visible de Jupiter<\/span><\/span><\/span><\/p>\n

Du <\/span><\/span><\/span>17 juillet au 24 ao\u00fbt, p\u00e9riode d\u2019observation \u2013 optimale du <\/span><\/span><\/span>11<\/b><\/span><\/span><\/span> au <\/span><\/span><\/span>15<\/b><\/span><\/span><\/span> ao\u00fbt dans des conditions moyennes <\/span><\/span><\/span>(Premier Quartier de Lune le 15 \u00e0 15 h 20 m)<\/i><\/span><\/span><\/span> – en seconde partie de nuit de l\u2019essaim m\u00e9t\u00e9orique des <\/span><\/span><\/span>Pers\u00e9ides <\/b><\/i><\/span><\/span><\/span>(\u00e9toiles filantes) <\/i><\/span><\/span><\/span> <\/b><\/i>avec un maximum th\u00e9orique d\u2019activit\u00e9 pr\u00e9vu le <\/span><\/span><\/span>12<\/b><\/span><\/span><\/span> ao\u00fbt vers 19 h <\/span><\/span><\/span>(Taux horaire au z\u00e9nith THZ pr\u00e9vu\u00a0: <\/i><\/span><\/span><\/span>100<\/b><\/i><\/span><\/span><\/span>, voir explications compl\u00e9mentaires dans les \u00e9ph\u00e9m\u00e9rides du mois d\u2019ao\u00fbt 2019)<\/i><\/span><\/span><\/span><\/p>\n

15 Premier Quartier<\/b><\/span><\/span><\/span> de Lune \u00e0 15 h 20 m<\/span><\/span><\/span><\/p>\n

16 <\/b><\/span><\/span><\/span>La Lune \u00e0 4\u00b0 au nord de l\u2019\u00e9toile Antar\u00e8s [Alpha Sco A (+1,2)] \u00e0 19 h<\/span><\/span><\/span><\/p>\n

17 <\/b><\/span><\/span><\/span>La Lune au p\u00e9ri<\/span><\/span><\/span>g\u00e9e <\/span><\/span><\/span>(\u00e0 369 127 km de la Terre \u2013 Diam\u00e8tre apparent\u00a0: 32\u201922\u2019\u2019)<\/span><\/span><\/span> \u00e0 9 h<\/span><\/span><\/span><\/p>\n

20<\/b><\/span><\/span><\/span> Jupiter (-2,9) en opposition avec le Soleil \u2013 d\u00e8s lors observable pendant toute la dur\u00e9e de la nuit \u2013 \u00e0 0 h<\/span><\/span><\/span><\/p>\n

Uranus (+5,8) stationnaire dans la constellation du B\u00e9lier \u00e0 4 h<\/span><\/span><\/span><\/p>\n

La Lune \u00e0 4\u00b0 au sud de Saturne (+0,3) \u00e0 22 h<\/span><\/span><\/span><\/p>\n

22<\/b><\/span><\/span><\/span> Pleine Lune<\/b><\/span><\/span><\/span> \u00e0 12 h 02 m<\/span><\/span><\/span><\/p>\n

Le <\/span><\/span><\/span>Soleil<\/b><\/span><\/span><\/span> entre dans le <\/span><\/span><\/span>signe<\/i><\/span><\/span><\/span> de la Vierge \u00e0 21 h 35 m alors qu\u2019il est pass\u00e9 de la <\/span><\/span><\/span>constellation<\/i><\/span><\/span><\/span> du Cancer dans laquelle il se trouvait depuis le 21 juillet dans la <\/span><\/span><\/span>constellation<\/i><\/span><\/span><\/span> du Lion le 10 ao\u00fbt<\/span><\/span><\/span><\/p>\n

24 <\/b><\/span><\/span><\/span>La Lune \u00e0 4\u00b0 au sud de Neptune (+7,8) \u00e0 2 h<\/span><\/span><\/span><\/p>\n

25 <\/b><\/span><\/span><\/span>D\u00e9but de l\u2019\u00e9t\u00e9 astronomique dans l\u2019h\u00e9misph\u00e8re bor\u00e9al de la plan\u00e8te Mars <\/span><\/span><\/span>(par ailleurs non observable)<\/i><\/span><\/span><\/span><\/p>\n

30 <\/b><\/span><\/span><\/span>La Lune \u00e0 l\u2019apog\u00e9e <\/span><\/span><\/span>(\u00e0 404 100 km de la Terre \u2013 Diam\u00e8tre apparent\u00a0: 29\u201934\u2019\u2019) <\/span><\/span><\/span>\u00e0 2 h<\/span><\/span><\/span><\/p>\n

Dernier Quartier<\/b><\/span><\/span><\/span> de Lune \u00e0 7 h 13 m<\/span><\/span><\/span><\/p>\n

Visibilit\u00e9 des plan\u00e8tes<\/h3>\n

Visibles \u00e0 l\u2019\u0153il nu\u00a0: <\/b><\/span><\/span><\/span>Jupiter, <\/span><\/span><\/span>Saturne<\/span><\/span><\/span><\/p>\n

Difficiles \u00e0 observer\u00a0: <\/b><\/span><\/span><\/span>V\u00e9nus, <\/span><\/span><\/span>Uranus, Neptune<\/span><\/span><\/span><\/p>\n

Inobservables\u00a0: <\/b><\/span><\/span><\/span>Mercure, Mars <\/span><\/span><\/span><\/p>\n

Mercure <\/b><\/span><\/span><\/span>(-1,9\/-0,0) passe au m\u00e9ridien le 1 \u00e0 11\u00a0h 50\u00a0m, le 15 \u00e0 12 h 41 m et le 31 \u00e0 13 h 09 m, d\u00e8s lors non observable <\/span><\/span><\/span><\/p>\n

V\u00e9nus<\/b><\/span><\/span><\/span> (-3,9\/-3,9), toujours difficile \u00e0 observer <\/span><\/span><\/span>(voir mois pr\u00e9c\u00e9dents)<\/i><\/span><\/span><\/span> le soir au coucher bas au-dessus de l\u2019horizon ouest d\u2019abord dans la constellation du Lion et ult\u00e9rieurement dans celle de la Vierge, se couche le 1 \u00e0 20 h 42 m, le 15 \u00e0 20\u00a0h 12\u00a0m et le 31 \u00e0 19 h 37 m soit respectivement 1 h 14 m, 1 h 09 m et 1 h 07 m apr\u00e8s le Soleil <\/span><\/span><\/span><\/p>\n

Mars <\/b><\/span><\/span><\/span>(+1,8\/+1,8) passe au m\u00e9ridien le 1 \u00e0 13 h 18 m, le 15 \u00e0 12\u00a0h 55\u00a0m et le 31 \u00e0 12\u00a0h 30\u00a0m, d\u00e8s lors non observable <\/span><\/span><\/span><\/p>\n

Jupiter <\/b><\/span><\/span><\/span>(-2,8\/-2,8), en opposition avec le Soleil le 20 \u2013 et d\u00e8s lors observable pendant toute la dur\u00e9e de la nuit <\/span><\/span><\/span>(le soir au-dessus de l\u2019horizon est, en milieu de nuit au-dessus de l\u2019horizon sud et le matin au-dessus de l\u2019horizon ouest)<\/i><\/span><\/span><\/span> \u2013 d\u2019abord dans la constellation du Verseau et ult\u00e9rieurement dans celle du Capricorne, se l\u00e8ve le 1 \u00e0 20 h 08 m, le 15 \u00e0 19 h 10\u00a0m et le 31 \u00e0 18 h 04 m <\/span><\/span><\/span><\/p>\n

<\/a> Saturne<\/b><\/span><\/span><\/span> (+0,2\/+0,3), en opposition avec le Soleil le 2 \u2013 et d\u00e8s lors observable pendant toute la dur\u00e9e de la nuit <\/span><\/span><\/span>(le soir au-dessus de l\u2019horizon sud-est, en milieu de nuit au-dessus de l\u2019horizon sud et le matin au-dessus de l\u2019horizon sud-ouest)<\/i><\/span><\/span><\/span> \u2013 dans la constellation du Capricorne, se l\u00e8ve le 1 \u00e0 19 h 24\u00a0m, le 15 \u00e0 18\u00a0h 27 m et le 31 \u00e0 17 h 21\u00a0m <\/span><\/span><\/span><\/p>\n

Uranus <\/b><\/span><\/span><\/span>(+5,8\/+5,7), le matin au-dessus de l\u2019horizon nord-est dans la constellation du B\u00e9lier, se l\u00e8ve le 1 \u00e0 22 h 24 m, le 15 \u00e0 21 h 29 m et le 31 \u00e0 20 h 26\u00a0m <\/span><\/span><\/span><\/p>\n

Neptune <\/b><\/span><\/span><\/span>(+7,8\/+7,8), une grande partie de la nuit au-dessus de l\u2019horizon est dans la constellation du Verseau, se l\u00e8ve le 1 \u00e0 20\u00a0h 51 m, le 15 \u00e0 19 h 55 m et le 31 \u00e0 18 h 52 m <\/span><\/span><\/span><\/p>\n

Pour en savoir plus :<\/i><\/span><\/span><\/span><\/p>\n

Annuaire 2021 de l\u2019Observatoire Royal de Belgique<\/a> ORB <\/span><\/span><\/span>(En vente \u00e0 l\u2019Observatoire : EUR 13,00)<\/i><\/span><\/span><\/span><\/p>\n

Eph\u00e9m\u00e9rides du mois dans la revue <\/span><\/span><\/span>Ciel et Terre<\/i><\/span><\/span><\/span> de la Soci\u00e9t\u00e9 Royale belge d\u2019Astronomie, de M\u00e9t\u00e9orologie et de Physique du Globe SRBA <\/span><\/span><\/span>(www.srba.be<\/a>)<\/i><\/span><\/span><\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

AVIS IMPORTANT\u00a0: Pour obtenir l\u2019heure officielle, ajouter DEUX heures aux heures indiqu\u00e9es ci-dessous (en Temps Universel UT pour Uccle) Ph\u00e9nom\u00e8nes c\u00e9lestes int\u00e9ressants 1 La Lune \u00e0 2\u00b0 au sud d\u2019Uranus (+5,8) \u00e0 0 h Mercure en conjonction sup\u00e9rieure avec le Soleil \u2013 d\u00e8s lors non observable \u2013 \u00e0 14 h 2 Saturne (+0,2) en opposition […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[51],"tags":[],"featured_image_src":{"landsacpe":false,"list":false,"medium":false,"full":false},"_links":{"self":[{"href":"https:\/\/robinfo.oma.be\/fr\/wp-json\/wp\/v2\/posts\/3620"}],"collection":[{"href":"https:\/\/robinfo.oma.be\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/robinfo.oma.be\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/robinfo.oma.be\/fr\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/robinfo.oma.be\/fr\/wp-json\/wp\/v2\/comments?post=3620"}],"version-history":[{"count":1,"href":"https:\/\/robinfo.oma.be\/fr\/wp-json\/wp\/v2\/posts\/3620\/revisions"}],"predecessor-version":[{"id":3621,"href":"https:\/\/robinfo.oma.be\/fr\/wp-json\/wp\/v2\/posts\/3620\/revisions\/3621"}],"wp:attachment":[{"href":"https:\/\/robinfo.oma.be\/fr\/wp-json\/wp\/v2\/media?parent=3620"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/robinfo.oma.be\/fr\/wp-json\/wp\/v2\/categories?post=3620"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/robinfo.oma.be\/fr\/wp-json\/wp\/v2\/tags?post=3620"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}