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               PHEMU03 Letter n°2
                  July 10, 2002
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Contents:
1) A new service on the Phemu03 web page for the observers
2) A new technical note on the observed light curves
3) The magnitude drop and the timing of an observation
4) An educational project
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1) A new service on the Phemu03 web page for the observers.

In order to help the observers to prepare the Phemu03 campaign, 
a new interactive software is available allowing to
ceterminate what events will be observable from any
site on Earth. You may choose a minimum elevation of Jupiter 
above the horizon in order to eliminate the events occurring
when Jupiter is not visible. The same type of criterion is
available for the elevation of the Sun. Some criteria on
the magnitude drop of the events and on the proximity of
the disk of Jupiter may be applied too.
Please try this software and tell us your comments.
This software is available from:
http://www.bdl.fr/ephem/ephesat/en/visiphemu_formulaire_eng.html


2) A new technical note on the observed light curves.

Some examples of light curves recorded during an observation
of a mutual event are presented in order to prevent the
observers from the errors leading to unusable light curves.
The new technical note (Technical Note n°8) is available
at the address:
http://www.bdl.fr/Phemu03/ntph08/ntph08.html


3) The magnitude drop and the timing of an observation.

I would like to remind you the two most important
thing to be careful when observing a mutual event:
- the measrement of the flux drop must be made in 
a linear scale i.e. the response of the photometer
must be proportional to the light flux. be careful
to eliminate the automatic gain of some camera and
don't forget to record reference objects of
different magnitudes;
- each photometric point must be refrred to Universal 
Time (UTC). All our observations will have to
be linked together with the same time-scale within 
0.1 second of time.


4) An educational project

The Galilean satellites are easily observable and
some amateur astronomers and students from high schools
are interested to participate to the campaign of observation
or to learn about astronomical observations and 
scientific research through the occurrence of
the mutual phenomena.
Please, if you know some high schools interested
in our observational campaign and in the study of
the galilean satellites, tell them to contact us. We
will put them in touch with the other high schools
interested and they will be able to correspond and
to exchange their experiences in observation.
A specific page is dedicated to this purpose at
the addresses:
http://www.bdl.fr/Phemu03/educphemu_eng.html
(in english)
http://www.bdl.fr/Phemu03/educphemu.html
(in french)

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Dr Jean-Eudes ARLOT
Institut de mecanique celeste
Observatoire de Paris/Bureau des longitudes
UMR 8028 du CNRS
77 avenue Denfert-Rochereau
F-75014 Paris
tel.: (33) 1 40 51 22 67
fax: (33) 1 46 33 28 34
e-mail: arlot@bdl.fr
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