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(meteorobs) I-V ALPO Classifications
-- [ From: Robert Lunsford * EMC.Ver #2.5.1 ] --
Lew,
I created these classifications a few years back in order to help ALPO
members plan their observations. This was strictly an ALPO scale and is
not officially recognized by any other organization. These
classifications are not permanent and a particular shower may move from
one classification to another depending on the recent activity. I
recommended (and still do) that novice observers stick to categories I &
II (IMO Showers) until they gain sufficient experience in all aspects of
meteor observing. I suspect an average observer would require
approximately 100 hours to achieve this goal.
The following is a brief description of each classification and example
showers:
Class I The strongest annual showers with ZHR's greater than 3 at
maximum activity. (QUA, LYR, ETA, SDA, CAP, PER, ORI, STA, NTA, LEO, GEM
, URS)
Class II Dependable minor showers with ZHR's of at least 3 at maximum
activity. (DCA, DLE, VIR, SAG, JPE, PAU, SIA, NDA, KCG, AUR, DAU, SPI,
EGE, AMO, XOR, MON, HYD, COM)
Class III Periodic showers that can produce strong activity one year
and be totally absent the next year. (Pi Puppids, Giacobinids, and
perhaps the Aries-Triangulids)
Class IV Minor showers that usually produce annual activity. ZHR's are
usually less than 3. Only experienced observers are advised to attempt
to resolve these showers from the sporadic background. (Mu Virginids,
Alpha Bootids, Theta Ophiuchids, Pi Eridanids, Kappa Aquarids, Annual
Andromedids, Sigma Orionids, and Delta Arietids are the best examples).
Class V Very weak showers not positively known to exist. ZHR's are
usually less than 1. Only photographic and radar methods can distinguish
these showers. Good examples are seen in the old IMO lists plus Gary
Kronk's book: Meteor Showers: A Descriptive Catalog.
All comments all welcome!
Bob Lunsford
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