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(meteorobs) Re: shower rates
Finally got a little free time now that the initial tax rush is over. Will
be quieter for about a month, then the final rush to April 15. People with
simple returns all pile in early for Rapid Refunds and Earned Income Credit,
a big giveaway. The complex returns are trickling in and will get numerous
by April.
Haven't had time to read all the messages yet. Have been limited to looking
only briefly every 3 or 4 days. Hale-Bopp is generating a lot of traffic
for the slow meteor season.
Here are my expected typical observed meteor rates for the major showers
that average observers can see under various conditions. I have oriented
these to central U.S. latitudes. Atypical shower returns are not used here
(except for ZHR's) which will cover most of the displays. Four rates for
each shower under the following conditions are given: 1) city sky or full
moon, 2) suburb sky or quarter moon, 3) rural sky and moonless, 4) ZHR
using the better years if a sharp observable peak occurs in your longitude.
Quadrantids.........5........10........25..........120
Lyrids...................4.........7...........15.........15
Eta Aquarids.......4........6...........10..........40
Delta Aquarids....4.......7............15.........20
Perseids..............10......20........40...........120
Orionids................5.........10.......25..........25
Taurids.................4..........6..........10.........10
Leonids................5.........10.........15..........15
Geminids.............18........35........85..........85
Ursids..................3............5.........10...........20
Five of the showers pass close enough to overhead that their ZHR's can be
taken as equal to the rural sky rate.
Quadrantids more often than not will give a display in the low 20's ; you
have to be fortunately placed to do better. The showers with unstable rates
(Eta Aquarids, Taurids, Ursids) I have used a comfortable average for.
Sharp-peak showers are Quadrantids and Perseids. The Leonids don't fit any
of these categories for the next few years ; these numbers cover their slow
years (1975-1994 the latest such period just completed).
Norman W. McLeod III
Visual Studies Coordinator
American Meteor Society, Ltd
Fort Myers, Florida