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Re: (meteorobs) RECENT METEOR SESSION


Congratulations on your first recorded observations, Jon! They look great! Did 
you have fun? If so, now's the time to start preparing for the Geminids in 
December, then the Quadrantids in January! (After that, there's a long stretch 
until April for the next high-rate showers for Northern observers: that lull 
would be a great time to learn meteor plotting, if you're interested!)


You asked a few very good questions in the report. I'm sure Mark Davis will 
answer them best, but here's my $0.02 on what you asked:

>PERIOD(UT)
>1100-1145
Be sure to put your times in "Universal Time", or Greenwich Mean Time. This is 5 
hours ahead of Eastern Standard time, 8 ahead of Pacific Standard, etc.

>           FIELD
>           140o dia
Here, be sure to note where your eyes were "centered" in the sky, rather than 
how wide your field of view was. So for instance, if you were facing the star 
Castor in Gemini while observing (a good spot for the Leonids), you'd put the 
ROUGH position of Castor down under this column: RA 7h30m, Dec +30.

>I don't know what "F" stands for.
This is a tricky one, but there's a formula for calculating "F" in the IMO Web 
pages I pointed you to: this is a "correction factor" for the amount of 
cloudiness you experienced while observing! Usually, for most observations that 
are "keepers" (relatively clear skies), your F should be less than 2. Anyway, 
while you're learning, just leave this one blank for now.

>2.Does "MAP" mean what map they would be located on (George is sending them)?
This is for plotting meteors. Right now (and during all major showers in fact!), 
you're just "counting" meteors rather than plotting them. So don't worry about 
this field right now, until you actually start plotting meteors later on.

>3.What does "ACCURACY" mean?
Again, this is only for meteor plotting. If you were plotting a meteor, and you 
were ABSOLUTELY SURE about the accuracy of your plot, you'd put a "1" here. If 
you're not so sure, but you have a good idea, you'd put a "2". If you're very 
uncertain where the meteor was in the sky, you'd put a "3" - lowest accuracy.

>4.Are my speed notes correct?
The speed doesn't actually refer to how long the meteor lasted, but how rapidly 
it covered the sky. Almost all the meteors you see will last less than 1 second. 
But suppose you saw one that lasted (in the ballpark of) 0.5 second. If it only 
covered a few degrees of the sky, you'd call this a very slow meteor! If on the 
other hand, you saw it arc all the way from western Orion into eastern Aries in 
that 0.5 second, it would be a VERY fast meteor! Basically, as George will tell 
you, this 0-5 "NAMN speed scale" is designed to be a subjective impression of 
how fast the meteor appeared to move in the sky. (George invented it!)

Many of the most experienced meteor observers actually don't use this scale, but 
instead try to estimate how many degrees-per-second the meteor was moving across 
the sky... If you feel you want to try this challenge (I don't do this myself), 
just post something to the list asking the experts how to do it! Otherwise, 
though, just try to pick a number between 1 and 5 (for non-point meteors) that 
gives a *relative* idea how fast the meteor you saw was.

For instance, almost all the Leonids you saw this weekend should have been 4s, 
with a few 3s and 5s. (The Leonids are a very fast shower!) If you saw any 
Taurids, though (very slow!), they should have been mostly 2s and 3s, and maybe 
one or two 1s if you were lucky to see a rare slow meteor!


Last but not least, a computer tip: be sure to use a "fixed pitch" font like 
Courier for your reports, to make sure all the columns of data line up right.

Hope this helps, and keep up the observing! You've already learned more about 
meteors than 90% of amateur astronomers out there, and there's always more!

Clear skies and many, many more meteors!
Lew
References: