[Avodah] L'Ayin Haya Noteh

[Micha Berger]

On Thu, Sep 06, 2012 at 09:06:59AM +0300, Liron Kopinsky wrote:
: At Rosh Chodesh, the sun should be ahead of the moon, thus making the moon
: appear like a backwards C. In such a situation, at sunset (which, Rashi
: says, is when the new moon is visible)

I'm pausing RLK here to add explanation to help people visualize...
Only the last paragraph of this post actually answers his question.

When there is no moon visible, the moon is on the same side of the earth
as the sun. (At least on the east-west axis. Unless there is an exclipse,
it's not lined up with the son on the north-south one.)

Then on Rosh Chodesh, the moon rises and sets just after the sun does.
So yes, right after sunset is the only time the moon is out at night.

And so on each day, rising and settinh slightly later, so that at the
full moon, the moon is entirely out of sync with the sun -- rising
when the sun is setting. This way, it rises 28.5 times in the 29.5 day
month; both numbers rough. And then they're lined up again.

:                                         the sun would be to the north of
: the moon, and therefore the crescent would be a backwards C with the points
: of the crescent pointing towards the south,

In the northern hemisphere, rising means heading south of east.
At noon the sun is south of the middle of the sky. And then it sets 
by heading north west. The sun and moon are never in the north half of
the sky, since we're looking southward to see things that are over
the equater.

This is why north is tzafon, from tzafun = hidden.

We said that on RC, the moon is slightly trailing the sun. So, after
noon it's slightly south east of the sun. And when the sun sets, it's
slightly south-east of the western horizon.

It will be the lower side that is nearer the sun, and thus lit up. So
the dark part, with the horns of the crescent above and below it, will
be pointing south-east -- away from the horizon (behind which the sun
is hiding). Looking like it's pointing back upward. Rashi would call
that pointing south.

: But Rashi, [RH 23b] DH L'Ayin Haya Noteh, says that the moon pointing
: north looks like this "[)" and pointing south looks like this "(]",
: which is the opposite of what I would expect.

North is ahead, and south is behind, on the trail of the moon shortly
before it sets. Within Hebrew text, a crescent that points ahead would
be (poorly) drawn as "[)". Picture if Rashi had written in English:
"The heads on either side of the missing piece were pointing which
way? Were they pointing north like this (] or to the south like [)?" By
translating to a language that goes the other way, my diagrams reverse.

Tir'u baTov!
-Micha

-- 
Micha Berger             For a mitzvah is a lamp,
micha at aishdas.org        And the Torah, its light.
http://www.aishdas.org                   - based on Mishlei 6:2
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