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Re: (meteorobs) Video/Minor Shower Radiants
from Marco Langbroek:
Hello George, Sirko (when back), and the rest
Knowledge of the position of the shower radiant for minor streams CAN be
significantly improved in one or just a few nights by video; Marc de Lignie
and his team did this for a number of streams on a number of occasions. Our
method always employs multistation triangulation, not mono-station radiant
determination. One good DMS video observing campaign was the Leonid
campaign of November 17-22. Apart from the leonid and alfa Monocerotid
outburst result, we obtained several new orbits for the Taurids, but also
other interesting less known streams; 6 'zeta Orionid' orbits, 6 northern
delta Arietids, and four 'beta Leonids' (coming from the back of Leo). That
is enough for a reliable radiant position to be assessed. Note that these
video results give radiant positions with similar accuracy to photographic
multistation radiant positions, i.e. accuracy better than one degree. And
that is better than possible from plottings.
The Orionid night of 21-22 October 1995 also resulted in a nice batch of
multistation video orbits among which 3 Leo minorids (adding to the 3
photographic orbits, amongst which one is a DMS orbit, that existed from
the previous decades in the IAU datafiles), a stream who's existence is
still denied by IMO but certainly exists. That same campaig resulted in 4
Taurid orbits as well and 32 Orionid orbits.
Concerning the radiant size, this indeed needs a substantial number of
radiant determinations, which might take longer than one or a few nights.
Radiant sizes anyway are always a problem, for somewhere the definition of
'what is a stream member and what not' comes in.
Anyway, while Sirko's comments are basically correct, I think he is
slightly too pessimistic regarding the determination of an accurate radiant
position ; for many minor streams, this will certainly take much less than
'a decade or so' and can be accomplished in a few nights (if you don't
believe Sirko; read Marc's papers! He did it already for some streams).
But, as Sirko remarked; video cannot be operational each night (and
certainly not multistation), the task of reducing all results would be
enormous (for one or a few nights, this already is!). Thus, no fear George;
visual observations remain very necessary and will remain for a long time I
think, for the majority of minor streams...!
Marco Langbroek
Dutch meteor Society
Casper ter Kuile, Dutch Meteor Society (DMS)
Akker 145, NL-3732 XD, De Bilt, The Netherlands
Tel. +(31)-30-2203170, Fax. +(31)-30-2202695
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