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Re: Radiants, was Re: (meteorobs) A blank meteor reporting form


 GeoZay>>Such as the "assumed" diameters of the Orionids being 10 degrees and
 >Leonids being 5 degrees? I'm really curious how NAMN can explain these
 >designators?<<
 
 mark>>Hi George,
 These are from the meteor shower calendar, which we use for our visual count
 programs. <<

Rainer Arlt told me about a year ago that these radiant diameters listed in
the IMO shower calendar are suppose to be deleted. It appears that it is a
matter of getting the word out so that future calendars won't have this
outdated information.

mark>>The tables you mention (8-3 and 8-4) I use with plots, so we are
 in agreement on that point.<<

This hasn't been in dispute all along. What is in dispute is the use of
erroneous radiant diameters to indicate the location of a radiant before any
meteors are even recorded. After a meteor is sighted, does the information on
tables 8-3 and 8-4 come into play. 

 mark>>Although useable for both types of observing,
 the form we are discussing is mostly used by observers for visual counts.
  >>

Visual Counts or Plotting, there isn't any necessity in listing a radiant
diameter on a meteor reporting form....particularly if it's some arbitrary
figure. It has no function in meteor recording. What is functional is an
understanding how the area around the actual radiant is enlarged in relation
to a meteor's distance from the radiant. As a meteor observer...whether Visual
Counts or PLotting, All you need to know is the "point" in the sky that the
radiant is located at. If you are plotting, all you have to do is draw a
circle small enough to put the appropriate three letters that are that
particular shower's Code letters for a reference point. As you see the
meteors, you then make a judgement call on whether a meteor's alignment is
within acceptance to a varying ballooned radiant in relation to it's distance
from the radiant. To get in step with IMO, you might want to consider removing
from your forms a radiant diameter for each shower. Or....Assign them all a
standard arbitrary size such as 5 degrees?  In the past, erroneous radiant
diameter sizes included 4, 5, 6, 8, 10, 10X5, and 15X10 degrees for various
showers. What's the meaning in labeling one shower at 4 degrees and another at
10 when it has no functional purpose? Again, I wouldn't know why you would
want to do that since there is no need to show a false radiant diameter
without the presence of a meteor....and that is going to vary depending upon
how far away the meteor is. 
George Zay