Re: total lunar eclipse Thurs. evening

["Tony Portoni" <tonyp@cc1.uca.edu>]

Dave Simmons wrote:

> In Jack Horkheimer's "Star Hustler" episode last week he mentioned a 
> luminousity scale used to rate the brightness of a lunar eclipse. I did 
> not catch the name (something like daw-john??), but the scale goes from 
> L-0 for darkest to L-4 for brightest. He quickly went through the visual 
> criteria used to do the rating.Would anyone have more information on 
> this scale or a reference?

I found this in the 1996 Astronomical Calendar in the section on 
eclipses. The standard scale for recording brightness variations at 
the middle of the eclipse was worked out by Andre Danjon.  The scale 
criteria is listed as follows:

L = 0  --  very dark eclipse, Moon almost invisible
L = 1 --  dark eclipse, gray or brownish coloration, details 
distinguishable only with difficulty.
L = 2 --  deep red or rust-colored eclipse, umbra usually having a 
very dark center and relatively bright outer rim.
L = 3 -- brick-red eclipse, umbra usually having a yellow or bright 
gray rim
L = 4 --  strikingly bright copper-red or orange eclipse, with very 
bright bluish tint where umbra and penumbra meet.

Hope this helps.  We'll be clouded out here in central Arkansas also.

Tony

BTW, the 1996 Astronomical Calendar is written by Guy Ottewell and 
published by the author at the Universal Workshop in the Dept. of 
Physics, Furman University, Greenville, South Carolina
____________________________

Tony Portoni, Instrument Tech. and amateur astronomer
University of Central Arkansas
Dept. of Physics and Astronomy
Conway, AR  72035
tonyp@cc1.uca.edu