v3 - Occultation

[wasellajam]

Hi, alonso, so the few reads I was enjoying the poem and piecing together the bits that disrupted but then I figured I should know vs assume the meaning of Occlultation. As often happens to me with scientific terms, the more I read the more confused I got.

asking eclipse vs occultation

There are a number of terms for these things:

conjunction:
When two objects have either the same right ascension or the same ecliptic longitude (usually as observed from Earth). That is, they lie in (almost) a straight line from the point of view of the observer. In the case of the Solar System, such as when the Sun and Venus line up from the point of view of an observer on Earth, this is a conjunction. (It is also a conjunction when Earth lines up between e.g. Mars and the Sun - it is an inferior conjunction from the point of view of Mars (but we can't observe from Mars)).

Furthermore, when Venus lines up between the Earth and the Sun this is an inferior conjunction, and when Venus lines up with the Sun but on the opposite side of the Sun then this is a superior conjunction. Thus the inner planets (Mercury, Venus) can have both inferior conjunctions and superior conjunctions with Earth while the outer planets (Mars, Jupiter, etc.) can only have superior conjunctions with Earth.

The "almost" in "almost a straight line" is important because the definition is by longitude. Although the planets are said to lie in the ecliptic plane, this is not completely flat - they do not all have the exact same orbit inclinations. Thus not every conjunction is a transit, occultation or eclipse - they do not pass directly in front or behind.

transit:
When an object passes in front of a larger object*, this is a transit. These are rarer than conjunctions because the objects need to be directly in line so that one can be seen crossing the other.

In the case of recent transit of Venus, when Venus passed in front of the Sun, the sunlight passing through Venus' atmosphere gave us the opportunity to collect data on its composition. When one of the moons of Jupiter pass in front of Jupiter itself* this is also a transit.

occultation:
When an object passes in front of a smaller object*, this is an occultation. The farther object is hidden by the nearer object. These are also rare** because, like transits, they also need to be directly in line so that the nearer object can be seen crossing in front of, and blocking out, the farther object.

Asteroids occulting stars are studied because while we can calculate the asteroid's orbit and its distance from us using its speed, knowing how gravity and orbits work, etc., we can't see clearly enough to determine the size (think few kilometres in diameter but millions of kilometres away). But when an asteroid passes in front of (occults) a distant star, the star is effectively a point source (looks tiny), from the amount of time the occultation lasts and the asteroid's speed we can calculate its size***.

eclipse:
The Moon passing in front of the Sun is, depending on the conditions, a partial eclipse, total eclipse or annular eclipse.

Clearly, by the definition, when the Moon fully blocks the Sun it is an occultation and when it only partially blocks the Sun it is a transit, but this is a special case and is called a solar eclipse rather than a transit or occultation. (Similarly when the Moon passes through the Earth's shadow - when the Earth is directly between the Sun and the Moon - it is called a lunar eclipse.)

The word eclipse comes to us via Latin and French from ancient Greek ekleipsis, from ekleipein 'fail to appear, be eclipsed', from ek 'out' + leipein 'to leave'. (see eclipse on Wikipedia)

This alignment is also known as a syzygy****.

* Smaller or larger as they appear to the observer, an asteroid is most definitely smaller than a star but because it is so much nearer it looks bigger.
** A lookup of occultations can return a long list so that it may not seem rare, but when you compare how many asteroids there are, and how many stars, in relative terms it actually does not happen very often.
*** We can set limits on its size, given that the "average" asteroid looks like a lumpy potato rather than being some nice, regular shape that would make it easy to work these things out.
**** We could keep adding terms and googling them all day... ;-)
***** There is no footnote with five *

So applying it to the poem is difficult for me, I may get there or I may not, here are some notes on my read hoping to identify what I can reconcile and what gets me stuck.

Occultation

Quiet how the sun is leaving me
with shades of color
faded. Shades, too, will disappear
with all my friends
and the adults
and you are still
nowhere to be seen.
At first I thought this was sunset, then eclipse, but regardless the sun is leaving, the signs it existed leaving too. At first the second "shades" made me think window shades, neat! but I left that behind. The use of "adults" set the Narrator's age as young. We're talking humans now, I am unsure as to who "you" is.

What else to do but read.
What else to do but listen to the cicadas
in late summer heat.
A beautiful setting of the scene, young but old enough to read.
You should know
how new the world is to me,
that I would have so many questions
As if a babe but not, now I'm thinking maybe The N is not human, but still younger than the sun: moon, earth, asteroid? None of the above? Red herring? Important clue?
yet the shadows from the pines
are reaching
as if other matters
were more urgent to you.
Enjoying this strong image, cabin in the woods surrounded by pointed trees, the urgency at first sounded sulky to me, now I'm at there's no urgency, just indifference.


My long dark shape
a smaller fear,
the shadows chant
answers, in exchange
for commitment of the body
to an unseen role,
rewarded with pleasure in lights;
chanting–
I enjoy the language here but have yet to figure out what it means or who the N is.

yesterday is a tail
the mouth of tomorrow is swallowing
if time is a circle, ergo,
today is for consuming
as the caterpillar of the leaf,
so the self of knowledge.
Ah, clarity. Ergo and self of knowledge seem stiff and unnecessary.

We were supposed to read
the book I was reading,
home together. I’ll look for you
one last time.
The sulking is back, the details that seem human, I get the loneliness here, but with all the gaps in understanding I'm left with I'm unsure what is gone.

So, I'd rather not get explanations, it's an enjoyable read I hope will somehow reveal itself or I will get a clue in someone else's critique. Just letting you know I've been reading and where I'm at with it.
Thanks for writing and posting.