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(meteorobs) 2002 Eta Aquarids
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Call for Observations
2002 Eta Aquarids
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Early May provides the opportunity to issue our first call for observations
of 2002. The Eta Aquarids begin showing up around April 19 and
reach maximum activity on May 5 with a ZHR of 60. The predicted time,
according to the International Meteor Organization (IMO), is at 0530 hours
Universal Time with the radiant being at right ascension 22h 31.8m,
declination -01 degrees. After the peak, activity will begin to decline
until the shower ends around May 28th. However, the Eta Aquarids should give
a nice show over a period of several nights around May 5th.
If you are successful in observing the shower, we would be interested in
hearing about how you did. Informal reports will be published at the NAMN
website as soon as possible. To be listed there, reports should
include your name, date of observation, time of observation - both beginning
and end, and a count of the number of meteors you saw. These counts should
be broken down into the various showers (Eta Aquarids, Sagittarids, etc.).
Also make sure to include the nonshower or sporadic meteors.
With a little bit of more information, your report can also be used to aid
in the study of the Eta Aquarids. It may seem daunting at first, but really
is not that much different than submitting an informal report. Reports
that include all of the needed information will be forwarded to the
International Meteor Organization (IMO) for archiving, and possible shower
analysis. To be included, your report should contain:
1. Date/Time of Observation - the date of the observation, plus the
beginning and ending times of all observing periods. This should be listed
in Universal Time (UT), but if you are unsure of how to convert your time to
UT, then use your local time and state what time zone you are in.
2. Effective Observing Time - try to make your observing periods a minimum
of one hour in length. Keep in mind that if you take a break during a given
observing period, you must subtract this time from the period. For example,
if you took a 10-minute break, you should make that observing period 70
minutes long so that you'll have 1 hour of effective observing time, which
is normally abbreviated as Teff. Also, if you record your data on paper,
or are plotting meteors, you must subtract that recording time from the
period as well. As a start, you might use about 10 seconds per meteor to
record all the appropriate data, 30 to 45 seconds per meteor if you are also
plotting.
3. Observing Field of View - the direction you are watching. Your field of
view can be recorded as a compass direction such as SE(45), but right
ascension and declination coordinates is the preferred format.
4. Observing Field Obstruction - you will often see this abbreviated as the
letter F. It simply refers to the amount of your field of view that is
blocked by trees, buildings or clouds. Note that this is a measure of how
much of the sky in your field of view that is blocked. It is NOT a measure
of the entire sky.
5. Limiting Magnitude - the limiting magnitude of the sky (often abbreviated
as LM) is the faintest star an observer can see. To estimate your LM, a
count of stars is made in designated fields. Using these star counts, you
obtain your results from tables provided by the IMO. More information,
including the areas to make the counts in, is available on the IMO website
at:
http://www.imodot net/visual/major01.html#table2
6. Observed Showers - for each observing period, give the number of Eta
Aquarids you observed. Also give the number of sporadics, or meteors from
any other shower you may have seen.
7. Meteor Magnitudes - this is an extremely important item. Magnitudes are
determined by comparing the brightness of each meteor to the brightness of
stars with known magnitudes. This requires some knowledge of the locations
and magnitudes of suitable comparison stars, or access to suitable star
charts. Star charts for making these magnitude estimates are available on
our website at:
http://www.namnmeteors.org/charts.html
To make reporting your observations easier, the IMO has a report form
including samples at http://www.imodot net/visual/imoform.html
NAMN has a worksheet you can use as an aid in making your report. It is
available as a Microsoft Word file by sending your request to me at the
address below.
A more thorough discussion of meteor observations is available at
both the IMO and NAMN websites. Especially useful for beginners is the NAMN
Guide to Meteor Observing. The Guide is also available electronically by
emailing me at the address below.
Good luck with your Eta Aquarid observations! I look forward to hearing how
everyone did.
Mark Davis, meteors@comcastdot net
Goose Creek, South Carolina, USA
Coordinator
North American Meteor Network (NAMN)
NAMN Website: http://www.namnmeteors.org/
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