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Re: (meteorobs) Re: Recording meteors while fatigued
Kim Youmans wrote:
>Multiple attestation: One several occasions I have discounted a flash
>only to have an observing partner immediately say, "there's one!" and point to
>the appropriate area of the sky.
When I started meteor observing my rates turned out to be low.
We conducted several observing sessions with a partner, and we
exchanged information about every more or less unsurely seen
meteor. It was most illuminating to find out what was a real
meteor and what was not. I was surprised to find several of the
dubious flashes to be meteors, since my partner sawq exactly
the same thing. Now I think I have a better feeling of what is
a real meteor. If someone has the chance to make this experiment,
it's worth trying.
Cathy Hall wrote:
>If I don't know with absolute certainty that it is a meteor, I don't
>call it.
This sounds very strict. It is certainly correct in the sense
of having a 'clean' meteor sample. Yet we should bear in mind
that the information we derive from visual observations are
STATISTICAL. The individual meteor is practically not interesting.
When averaging many many observations for an activity measure
(or other properties) we will be close to a 'true' value of an
'average observer'. The better the individual observer behaves
like this average observer, the more useful is his/her observation
in the case of bad coverage, e.g. an unexpected outburst.
Cathy, I noticed that your rates are at the lower end (as an
effect of your principle), but this should not worry you. The
most important thing for visual observations is do it in a CONSTANT
manner. If somebody has a constant history of observations it is
always possible to judge about a particular event quite confidently.
>I have never, ever, seen floaters at night.
Neither have I, but I have the impression they cause a twinkling
of stars when passing over them. This is a quite annoying effect
in my eyes, particularly when it is not close to the centre of
the field of view.
>However, it is interesting to see the effect of low light on your eyes,
>especially for coloured surroundings.
Yes, take a blue and a red book (having about the same 'brightness')
and watch them at night: The blue appears almost like a white book,
the red is black. (I just rechecked this in the basement of the
observatory...)
Lew Gramer wrote:
>My personal criterion is simple: if I
>catch something for which I can confidently estimate at least ONE of two
>pieces of information, I will count that as a meteor and record it. Those
>two pieces of information are meteor path and meteor magnitude:
That sounds like a good solution. It gives a sample of the unsure
fraction of meteors, of which several will be true according to my own
experience and that of list members here. Of course, this may smears out
the actual meteor shower information, but it is probably much more
trouble to leave out all +5 and +6 meteors. Yet we can encounter
a selective effect: You see something, you notice it could have
emanated from a known radiant, you say 'ok, then it could be real,
I plot it.' It prefers shower members to sporadics.
All this should not be sophisticated. A good way of doing is certainly
the alternate observing with companions and without. If only in a group,
group-effect can appear (the most terrible being competition on LM).
Ok, I gabbed enough on this and hope everybody continues observing
more or less as before...
Best wishes, Rainer
--
Rainer Arlt -- Astrophysikalisches Institut Potsdam -- www.aipdot de
Visual Commission - International Meteor Organization -- www.imodot net
rarlt@aipdot de -- phone: +49-331-7499-533 -- fax: +49-331-7499-526
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