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(meteorobs) NAMN Notes:July 2003
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NAMN Notes: July 2003
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Introduction:
NAMN Notes is a monthly newsletter produced by the North American Meteor
Network, and is available both via email, and on the NAMN website at:
http://www.namnmeteors.org
Contents:
1. The South Delta Aquarids...
2. The Other Aquarids...
3. Other Meteor Showers of July...
4. Upcoming Meetings...
5. For more info...
1. The South Delta Aquarids...
Summer has finally arrived for those of us in the northern hemisphere... and
with summer comes the complex of meteor showers known as the Aquarids.
The south delta Aquarids (SDA) reach a peak on July 28th with a radiant at
339 degrees, ie. RA 22h 36m, Dec -16, which is about 5 degrees to the right
of the star delta Aquarius. The radiant is the area of the sky that the
meteors seem to come from if you trace their path back in the sky. RA and
Dec refer to coordinates. RA stands for Right Ascension and can be
thought of as longitude in the sky. Dec stands for Declination and can be
thought of as latitude.
To see where these Aquarids come from, either plot the radiant on your star
atlas - or print off a copy of our 4 star charts available on the web
(set printer to landscape mode): http://www.namnmeteors.org/charts.html
Besides labelling RA and Dec, we have labeled a number of various
standard stars with their brightness figures (magnitude). You can use
these stars as easy comparisons for judging the brightness of the meteors
you see.
The ZHR for this shower is 20 meteors per hour. What is ZHR? It stands for
Zenithal Hourly Rate, and is the number of meteors that an observer would
expect to see, on average, if they are out under a dark country sky,
and if the radiant of the meteor shower is directly overhead at the zenith.
This means that if you want to see more meteors, get away from city lights
and try to observe when the radiant is high in the sky.
The south delta Aquarids are average velocity meteors at about 41 km per
second. They can be seen from about July 12th until August 19th. The
radiant of the shower moves as the days go by - it does not stay at one area
in the sky. To see a map showing this movement over July and August, check
out the website of the International Meteor Organization (IMO) at:
http://www.imodot net/calendar/cal03.html#Aquarids
If you would like to contribute to our knowledge of meteor showers by taking
detailed notes on this shower, our Observing Guide gives details
on what you should record. It's fairly basic....data for each meteor, such
as time, magnitude, shower affiliation, speed, and other comments such as
train or color. General information to record includes such things as how
dark your perceived sky is (limiting magnitude), and comments on weather and
cloud cover. Interested? Take a look at the