[Prev][Next][Index][Thread]
(meteorobs) Those pesky path lengths (was Re: OBSERVATION Aug 6/7 GRALE)
Lew wrote:
>BTW, on another note, Wayne pointed out something to me I had missed from
>the current IMO Handbook: radiant sizes must actually correlate with meteor
>path lengths! Because IMO believes that visual (and plotting) path accuracy
>decreases steadily with distance from the radiant, the further your meteor
>is from the radiant, the WIDER (in degrees) the radiant has to be for you
>to ID the meteor with that shower
It's not the accuracy of the plot which changes, it't the error of the backward
prolongation at the radiant which increases until a distance of 90 deg, then
decreases again. And yes, the radiant size to be considered for shower
association increases with larger distance of the meteor. This results from the
study of plotting accuracy and sporadic pollution. The loss of meteors due to
plotting errors should compensate the plus of misaligned sporadics. In the case
of major showers like the Perseids, shower association is much less problematic
since the portion of sporadic meteors is small, and hence the error in the ZHR
is fairly small even if all sporadics are counted as Perseids...
Rainer
-----------------------------------------
Rainer Arlt -- Visual Commission Director
International Meteor Organization
visual@imodot net
Home page of IMO: http://www.imodot net
-----------------------------------------