Date: Fri, 10 Feb 2006 16:41:28 EST
Subject: the moon
Hello - I wonder what this is?
tonight the moon has a huge circle of light, after a completely clear very dark circle closer to the moon then there is a huge light circle some distance from the moon coming after the dark circle I have never seen anything like it, also - not going through the moon in fact missing it all together there are two lines of light going through the darker circle but joining the huge circle of light, very strange but very beautiful, I would love to know what has caused this, and if there is a name for it.
Answer to Second Question:
Date: Sat, 11 Feb 2006 16:30:23 -0500
Subject: Re: the moon
From: "Eric Canali"
Glenn, et al:
It sounds like a regular 22 degree lunar halo (the "huge"one described),
but she is also commenting on a "dark" nimbus holding closer to the
moon. The "dark" she is describing may be the visual effect of the ice
crystals also sorting-out an area of predominantly reddish light close
to the moon, it's quite close if it's what I have in mind... only a
couple moon diameters wide -? - Sometimes these effects are seen along
with the big haloes, yet more often it is not. Sometimes though the
little reddish nimbus occurs without the big 22 degree halo being there
Also, do remember that the primary halo, out at 22 degrees, is in
itself a "hole" in the field of scattered light coming from the moon
through the blanket of airborne ice crystals... A "hole", yes, it's a
sharp drop-off point, inside of which there is much less scattered
light getting to our eye than one finds immediately at and after the 22
degree boundary. For my whole description of this process, refer to my
little essay on haloes on your website.
As for the "lines" she mentioned -we'd need a lot more description from
her than what we have so far - ideally, a drawing.
- ERIC CANALI
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