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(meteorobs) Re: Reviving the old "where to look" discussion (NOT!)
Lew,
When I was advising observers to look close to the radiant this was
meant for observing any potential January Coma Berenicids. Your method
of watching 20 to 30 degrees away from the radiant is perfectly
acceptable for major showers. The example listed in the IMO Handbook
uses a sporadic "pollution" of 2 meteors per hour and a major shower
producing 80 meteors per hour. It's stated that with a major shower in
progress at that strength the relative error (the number of sporadics
accidentally included) in shower association is only 2.5 percent. If the
hourly rate is only 4 (minor shower strength) then the relative error is
50 percent! Therefore under minor shower conditions it is imperative to
look closer to the radiant so that all of the shower members seen would
be short and slow. This most definitely aids in their identification.
Sorry I could not provide more hard numbers. Perhaps one of our more
mathematically gifted readers could comment.
Clear Skies!
Bob Lunsford
Lew Gramer wrote:
>
> Reopening the "perception coefficient" debate wasn't enough pot-stirring
> for me, so I thought I'd ask the following question. :)
>
> A statement was made not too long back, the effect that looking more than
> 15 degrees away from a radiant begins to introduce measurable errors when
> the observe attempts to trace meteors back to that radiant.
>
> I don't have my IMO observing guide handy, but I wanted to ask about the
> geometry and/or observational data behind this statement. Does observing
> at 20 to 30 degrees from the radiant (which I often do) really reduce my
> quality of radiant association? If so, how exactly, and by how much?
>
> (If this topic is inappropriate for IMO-NEWS, feel free to respond only
> to 'meteorobs', or to me privately if you wish.)
>
> Clear skies,
> Lew Gramer <GRALE>
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