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(meteorobs) Re: questions on observing



Robert Gardner wrote:
> 
> 1.)  Years ago we frequently saw the advice of "one should not face the
> radiant when observing meteors".  Is that ever good advice?
> 
The main reason for this advice is that meteors appear longer the
further one looks away from the radiant (up to 90 degrees that is!).
Meteors seen near the radiant are often one degree or less in length and
often difficult to detect, especially if they are faint. The drawback
to looking far from the radiant is you will see less activity. The
optimum distance would be between 30 and 45 degrees. At this range the
meteors are still long enough to be easily seen plus the radiant would
still be in your field of view allowing you to a chance to see most of
the activity.
 
> 2.) Number one was rather academic to me  when I graduated from viewing
> meteors in a reclining lawn chair to facing the zenith on an army cot.
> Is there anything wrong with this approach since the only data I am
> recording is either hand counters or a computer which I don't have to
> look at?
> 
Actually looking straight up is one of the worse possible areas to face!
In this part of the sky the volume of air is thinnest. This is great for
telescopic work but not for meteor activity. The closer to the horizon
one faces then the volume of air increases. More atmosphere means more
meteor activity. The problem is that the closer one looks toward the
horizon, more of ones field of view becomes blocked by the ground. The
best compromise would be to look 45 to 60 degrees high allowing you to
see more activity but also preventing the ground from blocking any large
fraction of the action.


> 3.) Also number one is hard to observe in light of the fact that by dawn
> the radiant of at least the Perseids and the Leonids are very near the
> local meridian.  In fact I thought that a criteria for a good shower was
> that the radiant would be in the direction of the earths motion at dawn
> which these two are.  Is that true?  

The main criteria for a good display is to have the radiant as high as
possible in ones sky. Having the radiant in the direction of the earths
motion at dawn only provides swift meteors, nothing more. The best
possible scenario would be to have a radiant near the zenith at
midnight. This scenario is best filled by the Geminids, normally the
most active major annual shower.

 
>It has been a long time since I
> observed the Geminids but I do not think that was true of them and it
> was a good shower in quantity but lacked quality.
> 
You must associate quality with a high percentage of persistent trains.
Meteor showers having a swift average velocity such as the Perseids and
Leonids will present more train activity. The Geminids are much slower
than either of these showers and the percentage of persistent trains is
less than 5 percent. The first time you witness a fragmenting Geminid
fireball will change your mind about the quality of this display. 

Bob Lunsford
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