Riporto un alert apparso su "meteorobs", attenzione che da questa notte, 19-20 al 25 Ottobre potrebbe aumentare il numero di Orionidi, per arrivare a ( secondo questa previsione ) anche a ZHR 40-50:
"I am Mikiya Sato. I send the information of Orionids.
This year, two trails will approach the earth by my simulation.
The forecast of peak time is as follows;
-1265 trail : 206.8 - 207.7, Oct.20 11h - Oct.21 9h (UT)
-910 trail : 209.9 - 211.5, Oct.23 23h - Oct.25 4h (UT)
However, the usual peak time about 208-209 (solar longitude, day of
Oct 21-22) was also active in 2008 and 2009.
I think that this enhanced activities at usual peak might be caused
from an effect of older dust which I can not calculate.
So, the peak will be broad, between Oct 20 and 25.
The expected max. ZHR is 40-50, it is the same level as one in 2009.
Next year's activity of Orionids will return to the normal level,
before 2006. So, it is a final chance to observe an enhanced Orionids
in this year. The moon condition is very bad, but I hope that
many people try to observe Orionids.
Additional remark :
The dust of -1265 trail and -910 trail is in a mean motion resonance
of Jupiter, its ratio is 1:6. So the structure of the dust trail is kept.
I do not have a information about the older dust, however, I think that
the older dust which have an active effect may also be in a
same resonance.
Best wishes,
Mikiya Sato (National Astronomical Observatory of Japan)"
Saluti
Ferruccio
Titolo: alert Orionidi 2010 
Mar Ott 19, 2010 7:04 pm
