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re: (meteorobs) Zenith Attraction Quuestion
GWG wrote:
So, for radiants from meteors like the alpha Caps, the effect is enough
to make it hard to determine an accurate radiant from mid-northern
latitudes.
Is this a reason why sorting the Aquarid/Capricornid radiant complex is so
difficult to do from mid-northern latitudes??
I don't think that's the problem George. IMHO, it's really that there are 5
showers, all at barely detectable visual levels, all at low elevations,
within about a 30 degree area.
Other than the SDA's (when they are most active ZHR 20), all the other
showers are at or barely above visual detection levels if they are at the
zenith.
Since they are much lower, we see even less. (At 30 deg elev observed rate
is ~ 50%, at 10 deg elev 17%). At these rates, plotting is the best way to
verify membership, along with speed determination, and all these showers
are very close in speed (NDA 42 kps, SDA 41, PAU 35, SIA 34, NIA 31, CAP
25). When you place the radiants on a map you can see they overlap, and
depending on your field of view, some are in a direct line with each other
further complicating the problem. It requires great care. The zenith
attraction, maybe as much as 3 degrees is swamped by the close proximity
and close sppeds making differentiation difficult.
That's what I think anyway, for what it's worth.
Wayne