(meteorobs) Miscellaneous questions

[Roberto G.]

> Thanks Robert for your answer !
>
> But that brings another question to my mind ! Does anyone now why the 
> activity
> profile of Geminids has such a shape ? Is it similar to other showers ? 
> Are
> there any sources for which the profile is the inversal (that means a very 
> fast
> increase of activity, and then a slower decrease) ?
>
> For information, just look at the Ursid briefly yesterday (one hour, but 
> quite
> tired, so didn't make a real session), and saw 4 nice Ursids. It was 
> around 20h
> 00 UT-21h 00 UT.
>
> Thanks in advance !
> Karl

The Quadrantids show a similar shape, more strong of Geminids, this is the 
effect of
the separation by mass of meteors by solar action, in Quadrantid we see a 
peak of
radio meteor (+8a, +9a meteors) 17 hour before the optical maximum, then 
follow
a peak of bolid some hour after, naturally this "peak" it's very little, in 
a place it
can to be see perharps a very big bolid each 10 year (this it's only a 
number no real).
On the question on the shape: the profil of shape of Geminids was studied in 
the
last near a century and changed from the inverse of today at the actual 
profile,
and following this studies the shower should end in the next years but we 
can see
that this shower is incresing his ZHR, for data on this question you can 
read
the "Handbook visual meteor observations" edited by Paul Roggemans in
1987, pag 130-131-132, there is a new edition but I not read it.
Best greetings.
Roberto Gorelli