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(meteorobs) Perseid radiant positions
Greetings all,
Robert Gardner asked:
>I was asked why the radiant of the Perseids is in the constellation of
>"Cepheus". Actually it is in the constellation of Cassiopeia. I notice
>that my pencil scratches in an old atlas places the radiant in
>Perseus. What is the correct answer?
The radiant moves! To see a map of the Perseid radiant positions, look at:
http://www.amsmeteors.org/imo-mirror/calendar/cal99.html#Perseids
This map was in the 1999 International Meteor Organization calendar. The
maps are usually included in the years where the shower is highlighted, ie.
not hampered by the moon.
As you can see, the radiant moves a bit from night by night, so can cross
constellation barriers! We tend to (generally) call the meteors by the
constellation that the radiant is in at maximum... but we have to be aware
that if we are observing on other nights, the radiant may not be where we
think it is.
It is always good to check radiant positions before going out observing. A
table showing the positions for all the showers on the 2001 IMO "Working
List" can be found at:
http://www.amsmeteors.org/imo-mirror/calendar/cal01.html#Table6
and easy maps to see where these radiant positions are, can be found at:
http://www.namnmeteors.org/charts.html
For more details on the Perseids, and all the other showers visible right
now as well, check out our current issue of NAMN Notes at:
http://www.namnmeteors.org/namnnotes0108.html
Clear skies!
- Cathy Hall
NAMN, North American Meteor Network
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