Λεοντίδες (LEO): 06 ως 30 Νοεμ. Μέγιστο: 18 Νοεμ. 2011

[Bi2L]

Leonids (LEO)

πηγη imo.net

http://www.imo.net/calendar/2011#leo

Active: November 6–30; Maximum: November 18, 03h40m UT (nodal crossing

at λ⊙ = 235.27°), but see below; ZHR = 20+?;

Radiant: α = 152°, δ = +22°; Radiant drift: see Table 6;

V∞ = 71 km/s; r = 2.5;

TFC: α = 140°, δ = +35° and α = 129°, δ = +06° (β > 35° N);

or α = 156°, δ = −3° and α = 129°, δ = +6°(β < 35° N).

IFC: α = 120°, δ = +40° before 0h local time (β > 40° N);

α = 120°, δ = +20° before 4h local time and α = 160°, δ = 0° after 4h local time (β > 0° N);

α = 120°, δ = +10° before 0h local time and α = 160°, δ = −10° (β < 0° N).

 

The most recent perihelion passage of the Leonids' parent comet, 55P/Tempel-Tuttle, in 1998 may be more than a decade ago now, but the shower's activity has continued to be fascinatingly variable from year to year recently. This year might produce enhanced rates (though these may be observable using only particularly sensitive radio and radar systems), and theoretical work has suggested there may be several peaks. Jérémie Vaubaillon has indicated part of the 1800 AD dust trail may be encountered around 22h36m UT on November 16, and could produce ZHRs of ∼ 200. Unfortunately, the dust particles involved are expected to be exceptionally small, of order 10–100 microns, and this could mean no optically-detectable meteors at all. This activity may be observable instead as an increase in underdense radio meteor echoes, by those systems capable of recording the equivalent of such 'invisibly-faint' meteors, and by sensitive radar meteor systems. Mikhail Maslov has proposed that there may be two peaks, one on November 17, around 21h UT, when ZHRs may be ∼ 5–10 above the underlying 'normal' activity, the second on November 18 near 23h UT, with ZHRs of ∼ 10 above normal. Taking the typical ZHR to be ∼ 10–15 could suggest ZHRs at either might be ∼ 20 ± 5. The second peak he noted may produce somewhat fainter than average meteors, however. Another potential maximum time is that given above for the nodal crossing, when ZHRs are liable to be simply 'normal'.

 

Whatever the case, the Moon is bright and waning from full on all three dates, with last quarter on November 18. Thus it will be on-view throughout the time the Leonid radiant is usefully-observable, from about local midnight onwards (or indeed afterwards south of the equator). This will make even the typical activity difficult enough to see, but if there are any faint to very faint meteor maxima as well, these could pass entirely unobserved by optical or imaging methods. The November 16, and November 18 ∼ 23h, peak timings would be best-detectable for sites at eastern European longitudes eastwards across most of central Asia. That on November 17 would be similarly available from places with longitudes equivalent to the Near East east to eastern Asia, while the ∼ 04h peak on November 18 would be ideal for European longitudes. Note that other possible maxima are not excluded by these expectations! All observing techniques can be usefully employed, avoiding facing the Moon for optical and imaging work, naturally. VID has indicated weak Leonid activity might be detected for a much longer interval than had been previously suspected, and though this remains unconfirmed visually, the active dates for the shower have been expanded accordingly this year.

[Quaoar]

Παρα πολυ ωραια ιστορια και ευτυχως που διασωθηκε!!!

Μακαρι και ο καιρος να βοηθησει την Παρασκευη!!!

[Bi2L]

Γεια σου Κέρκυρα!!!

Χαίρομαι που έχουμε όλο και περισσότερες συμμετέχεις απ'το νησί

 

αν και η βροχή δεν θα είναι κάτι τρελό, αφού μιλάμε για 20+ διάττοντες την ώρα, όπως επίσης ότι θα θα έχουμε Φεγγάρι στο τελευταίο Τέταρτο και περίπου 16° απ'το ακτινοβόλο αλλά αυτό δεν θα μας αποτρέψει να ανέβουμε στο Κοράκιο όρος (στην Πηλίδα δηλαδή) και να κάνουμε παρατήρηση και καταγραφή της βροχής, μακάρι βέβαια να έχουμε καλό καιρό

 

 

Υγ

όσοι δεν διαβάσατε για τον Παπασαββανή ρίξτε μια ματιά στο κείμενο παραπάνω αξίζει

[Bi2L]

Το Θέμα διαχωρίστηκε, ΒΡΟΧΗ ΔΙΑΤΤΟΝΤΩΝ «ΛΕΟΝΤΙΔΕΣ» 1866

εδω: http://www.astrovox.gr/forum/viewtopic.php?p=175589

[Quaoar]

Σημερα διαβαζω σε ολες τις ιστοσελιδες οτι....

Το φαινόμενο θα κορυφωθεί τη νύχτα της Τετάρτης 16 προς Πέμπτη 17 Νοεμβρίου και θα είναι ορατό από τη 1 μετά τα μεσάνυχτα μέχρι τις 4.30 τα ξημερώματα.

 

Πρόκειται για μια πλούσια βροχή διαττόντων που εμφανίζεται κάθε χρόνο αυτή την περίοδο. Το θέαμα αναμένεται να είναι αρκετά έντονο, με την εμφάνιση περίπου 75 μετεώρων ανά ώρα, σύμφωνα με τον διευθυντή του Πλανηταρίου του Ιδρύματος Ευγενίδου, Διονύση Σιμόπουλο.

 

Δηλαδη 24 ωρες νωριτερα....

Ποια ημερομηνια ισχυει κανονικα?

[Bi2L]

Χάρη υποθέτω ότι το έχουν γράψει λάθος και να έχουν πάρει δεδομένα από προηγούμενη χρονιά, εκτός και αν υπάρχει και άλλο Μέγιστο το οποίο δεν έχει δημοσιευθεί στο Imo.net

 

edit: ότι λεει το imo.net

 

The most recent perihelion passage of the Leonids' parent comet, 55P/Tempel-Tuttle, in 1998 may be more than a decade ago now, but the shower's activity has continued to be fascinatingly variable from year to year recently.

This year might produce enhanced rates (though these may be observable using only particularly sensitive radio and radar systems), and theoretical work has suggested there may be several peaks. Jérémie Vaubaillon has indicated part of the 1800 AD dust trail may be encountered around 22h36m UT on November 16, and could produce ZHRs of ∼ 200. Unfortunately, the dust particles involved are expected to be exceptionally small, of order 10–100 microns, and this could mean no optically-detectable meteors at all.

This activity may be observable instead as an increase in underdense radio meteor echoes, by those systems capable of recording the equivalent of such 'invisibly-faint' meteors, and by sensitive radar meteor systems.

Mikhail Maslov has proposed that there may be two peaks, one on November 17, around 21h UT, when ZHRs may be ∼ 5–10 above the underlying 'normal' activity, the second on November 18 near 23h UT, with ZHRs of ∼ 10 above normal. Taking the typical ZHR to be ∼ 10–15 could suggest ZHRs at either might be ∼ 20 ± 5. The second peak he noted may produce somewhat fainter than average meteors, however. Another potential maximum time is that given above for the nodal crossing, when ZHRs are liable to be simply 'normal'.

 

 

Whatever the case, the Moon is bright and waning from full on all three dates, with last quarter on November 18.

Thus it will be on-view throughout the time the Leonid radiant is usefully-observable, from about local midnight onwards (or indeed afterwards south of the equator).

This will make even the typical activity difficult enough to see, but if there are any faint to very faint meteor maxima as well, these could pass entirely unobserved by optical or imaging methods. The November 16, and November 18 ∼ 23h, peak timings would be best-detectable for sites at eastern European longitudes eastwards across most of central Asia.

That on November 17 would be similarly available from places with longitudes equivalent to the Near East east to eastern Asia, while the ∼ 04h peak on November 18 would be ideal for European longitudes. Note that other possible maxima are not excluded by these expectations!

All observing techniques can be usefully employed, avoiding facing the Moon for optical and imaging work, naturally. VID has indicated weak Leonid activity might be detected for a much longer interval than had been previously suspected, and though this remains unconfirmed visually, the active dates for the shower have been expanded accordingly this year.

[astrovox]

Υπάρχουν διάφορα πιθανά μέγιστα σύμφωνα με τις προβλέψεις ενώ ανάλογα με το που στη Γη είσαι μπορεί κάποια μέγιστα να πέφτουν την ημέρα ή με το ακτινοβόλο πολύ κάτω από τον ορίζοντα.

 

Το κείμενο στα αγγλικά στο πρώτο post τα αναλύει όλα. Με λίγα λόγια, μάλλον η μεγαλύτερη πιθανότητα για εμάς είναι πριν την ανατολή της 18ης Νοεμβρίου.

 

Οι παρατηρήσεις που θα γίνουν μπορούν να βοηθήσουν να επαληθευτούν ή να βελτιωθούν τα μοντέλα.

[Bi2L]

Πολύ λίγα πράγμα είδαμε χθες, κρίμα το ξενύχτι... περισσότερους Ταυρίδες, Διδυμίδες & Σποραδικούς είδαμε παρα Λεοντίδες

[astrovox]

Βασίλη δυστυχώς οι δόξες των Λεοντίδων έχουν περάσει. Όποιος πρόλαβε προς δεκαετίας είδε πολλά αλλά τώρα απλά φθίνουν...

[tolis45]

Βασίλη,

 

Οι δυνατές εξάρσεις των Λεοντίδων συμπίπτουν

με την επιστροφή του πρόγονου κομήτη, 55P/Tempel-Tuttle ,

στο περιήλιο. Η τελευταία επιστροφή ήταν το 1998, η επόμενη

το 2031 +- 1 έτος. 20 χρονάκια ακόμα..

 

 

Τόλης.