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(meteorobs) Re: NM determining perception
Jure,
In regard to your question,
>How do you measure perception? Do you consider the FOV size? Mean LM for an
observer?
>Or is it just the number of meteors?
I determine perceptions relative to what I see. With my data available from
throughout the year, any night anyone observes under any sky condition, I
can come up with their perception. If our sky LM's differ I can either
correct to reduce mine, or raise theirs, using my own system. Then compare
the rates directly. Most observers have a FOV as big as they can get by
getting away from obstructions so I don't need that.
My perception is set arbitrarily, but not totally arbitrarily, at 1.0.
There is much evidence to show that I am very close to normal. From old
books going back several decades are shower rates that I still see today,
particularly Lyrids (15/hr), Eta Aquarids 10-15, Orionids 25, Taurids 15,
and Leonids away from storm years 10-15. The other showers have changed
with time.
Around 1981 Jeff Wood in Australia had a large group of observers recruited
from school. He compared my rates with his group and found I was almost
right in the middle : half of them saw more, half saw less. Jeff himself
rated 1.95 ; the group leader usually has the highest perception which
sustains his interest the longest, for obvious reasons.
Among all the people I have ever observed with, either casually or
systematically, the majority of them have seen between 70% and 130% of my
rates. I keep landing in the middle.
Thus far I haven't lost any eyesight. The sky looks the same as always, and
I still see the same general rates as in my early days. In 1973 Bill Gates
did an interesting study of our group of five, observing from the Keys in
July. He compared our perceptions hour by hour to the group average. I was
the only one that had no spikes or slumps. In our five-hour sessions, Gates
himself was best during the third hour with perception 5.0 ! His first hour
he was in a stupor (his term) with perception only 2.8, and by the final
hour he fell back to about that level.. Overall Gates worked out to 3.8.
It would be difficult to keep up long-term interest if I were seeing 20%
less, and impossible at 30% less. My first observing partner had poor
eyesight with perception 0.5 ; once college started, he quit for good.
Three others in the early group were just a shade below me. So I thought I
had very good eyes for meteors. When someone with 1.5 came along in 1963, I
could not understand how anyone could see more meteors than me.
There are other ways to determine perception, to be sure. Results vary
depending on where you start.
Norman
Norman W. McLeod III
Asst Visual Program Coordinator
American Meteor Society
Fort Myers, Florida
nmcleod@peganet.com
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