[vsnet-chat 623] Lunar magnitude during the forthcoming eclipse

[Alfredo Jose Serra Pereira <apereira@correio.cc.fc.ul.pt>]

Dear chatters,

Regarding the forthcoming September 16 total lunar eclipse, we would like 
to invite those in regions with a favorable view of this event, to 
participate in the campaign to estimate the Moon's total visual magnitude.  

The moon's integrated magnitude during a total eclipse is a sensitive 
indicator of volcanic and other aerosols in our atmosphere, as it is the 
refraction of sunlight in the Earth's atmosphere that accounts for the 
appearance of the eclipsed moon.

Even though the theoretically predicted lunar magnitude during the 1992 
December 9 eclipse was -1.5, due to the Pinatubo volcano eruption, the 
observed magnitude was +3.0 !   A 4.5 mag. difference, easily discerned, 
even if in this sort of measurement we probably have to contend with 
larger errors than for ex. in variable star visual estimates. 

It has been shown that the dimming of the eclipsed Moon caused by aerosol 
excess, correlate with temporary episodes of global cooling.  Continued 
monitoring of the lunar magnitude during eclipses, enables correlation 
with satellite obtained data, and in turn allows estimates of aerosol 
content to be made from old lunar eclipse obs, when satellite monitoring 
was not available.  The results are thus valuable to Global Change 
scientists, vulcanologists, and geophysicists in general.

We strongly urge individuals in the favored areas, to participate in 
this lunar magnitude campaign, and we encourage interested observers to 
contact us at: apereira@fc.ul.pt

You can find extensive information on the campaign at:  

http://correio.cc.fc.ul.pt/~apereira/lun_ecl_9709.html

If there is difficulty or slowness reaching our web site, we will be 
delighted to provide the articles upon request via e-mail.
Happy observing!  

Alfredo Pereira and Catarina Vitorino  
apereira@fc.ul.pt   http://correio.cc.fc.ul.pt/~apereira  
R. Antero de Quental, 8, 2 Dto, 2795 Carnaxide, PORTUGAL

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