"JBortle" wrote in message
...
A brilliant crimson-red Class IV aurora is in progress as seen from
southeastern NY. At 00:00UT fully 80% of the sky is covered with auroral
light
and there is a long whitish band that extends east-west within 10*-15* of
the
SOUTHERN horizon. Display seems to go back and forth from rayed and
structured
to simiply a strong but diffuse glow at about 15 minute intervals.

Hi John,

I recognize the advanced observer... speaking of classes ;-)
Can you remind us the auroras classes ?
A URL is also good.
I knew them in the past but today I do not more remember at all the
classification
Do it refer to the sun/moon position or brightness ?

Thanks
Thierry
http://www.astrosurf.com/lombry


JB