Re: 浮云啊浮云# Joke - 肚皮舞运动
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For those who may not have heard about it yet: there is going to
be a partial eclipse of the Sun this Sunday, May 20.
From the SF area, the Moon will cover about 90% of the Sun at
maximum eclipse, which will happen at about 6:30 pm in the
evening. The Sun will be low in the sky by then, so you'll need
not only a clear sky but also a good view to the west to see it.
** It's very important NOT to look directly at the Sun any time
during the eclipse (or any other time). **
Fortunately there are lots of other fun ways to view the eclipse.
You can make a pinhole projector, or you can get your hands
on some special glasses made especially for the purpose (that
block more than 99.9% of the Sun's rays... regular sunglasses
are NOwhere near dark enough). I've attached some more
information and links about eclipse viewing.
The whole event will last more than two hours. As viewed
from San Francisco, the Moon will start taking a bite out of the
Sun around 5:15 pm and won't move completely out from in front
of the Sun until about 7:40 pm (just before sunset). Maximum
eclipse will be at about 6:33 pm.
Here's a google map that NASA put together. You can zoom
in to any place you like and click on it to get more information
about what the eclipse will look like from there.
http://eclipse.gsfc.nasa.gov/SEgoogle/SEgoogle2001/SE2012May20A
You'll notice that San Fransicso is not in the direct path of the
eclipse. That's why from here only 90% of the Sun will get
covered up. If you're ambitious and want to see more of the
Sun covered up, you can drive north and/or east ~3+ hours and
see the Moon cover 95% of the Sun. From anywhere in the path
shown on the map you'll see an annulus, i.e. a ring of Sun
surrounding the Moon. But there won't be a total eclipse from
anywhere because on May 20 the Moon will be farther away than
usual so it won't appear quite big enough to cover up the Sun.
Some places in the east bay are holding special events (and
have ideal viewing spots up in the Oakland/Berkeley hills).
http://www.chabotspace.org/calendar.htm?date=5-20-2012&p=143935
http://events.berkeley.edu/index.php/calendar/sn/lhs.html?event
Any other place from which you can see the Sun low in the sky in
the west will be good, as long as the weather is clear and you have
a way to view the eclipse (e.g., pinhole projector; see attachment).
Let's hope for clear skies.
TIPS FOR VIEWING THE PARTIAL SOLAR ECLIPSE ON MAY 20, 2012
(1) PINHOLE PROJECTOR
A really good way to view the eclipse is to make a pinhole
projector out of a cardboard box or a wide cardboard tube.
What you do is cut a hole in one side of the box and tape a piece
of aluminum foil over it. Then you poke a small hole in the foil
(e.g. with a safety pin). If you point this hole at the Sun
you'll get an image of the Sun on the opposite inside wall of
the box.
To view the image you need a way to look inside the box. One
way is to cut the flaps off and turn the box upside down over
your head. Just be sure NOT to look at the Sun through the pinhole!
You only want to look at the projected image of the Sun. Another
way is to cut a couple of viewing windows in the sides of the box.
You also might want to tape a piece of white paper on the inside
wall of the box where the image appears so it will be as bright
as possible.
It's best to start with big box, if possible (e.g. at least 30"
long in one dimension). The size of the image of the Sun will
be proportional to the size of the box (or tube). A 30" box
will produce an image about 6 mm (1/4 inch) across. A 60" box
will produce an image twice that size, etc.
I'd recommend making the box in advance and then trying it out
on the Sun ahead of time to get used to how to point it at the
Sun and where will appear, etc. Any day will do.
The exploratorium has some instructions (and pictures) about
how to use a mailing tube to make a pinhole projector (same
idea, but a little harder to point at the Sun than a box).
http://www.exploratorium.edu/eclipse/how.html
(If you scroll down to the bottom of the exploratorium's page,
you'll also find a "quick and easy" way to view it, which just
involves a couple of pieces of cardboard. This is worth trying,
but keep in mind that the image of the Sun won't be that bright,
so it can be a little hard to see in the glare of everything else--
that's the reason it's worth using a box or tube if you can.)
(2) ECLIPSE GLASSES
Another option is to get your hands on a pair of glasses
that are specially designed for viewing the Sun (regular
sunglasses are nowhere near dark enough!). The special
glasses block out more than 99.9% of the Sun's rays.
Here's a link to one place that sells them:
http://www.rainbowsymphonystore.com/eclipseshades.html
(3) SPECIAL EVENTS
Chabot Space and Science Center and Lawrence Hall of Science
are both holding events:
http://www.chabotspace.org/calendar.htm?date=5-20-2012&p=1439355
http://events.berkeley.edu/index.php/calendar/sn/lhs.html?event_ID=50856&date=2012-05-20
Enjoy
be a partial eclipse of the Sun this Sunday, May 20.
From the SF area, the Moon will cover about 90% of the Sun at
maximum eclipse, which will happen at about 6:30 pm in the
evening. The Sun will be low in the sky by then, so you'll need
not only a clear sky but also a good view to the west to see it.
** It's very important NOT to look directly at the Sun any time
during the eclipse (or any other time). **
Fortunately there are lots of other fun ways to view the eclipse.
You can make a pinhole projector, or you can get your hands
on some special glasses made especially for the purpose (that
block more than 99.9% of the Sun's rays... regular sunglasses
are NOwhere near dark enough). I've attached some more
information and links about eclipse viewing.
The whole event will last more than two hours. As viewed
from San Francisco, the Moon will start taking a bite out of the
Sun around 5:15 pm and won't move completely out from in front
of the Sun until about 7:40 pm (just before sunset). Maximum
eclipse will be at about 6:33 pm.
Here's a google map that NASA put together. You can zoom
in to any place you like and click on it to get more information
about what the eclipse will look like from there.
http://eclipse.gsfc.nasa.gov/SEgoogle/SEgoogle2001/SE2012May20A
You'll notice that San Fransicso is not in the direct path of the
eclipse. That's why from here only 90% of the Sun will get
covered up. If you're ambitious and want to see more of the
Sun covered up, you can drive north and/or east ~3+ hours and
see the Moon cover 95% of the Sun. From anywhere in the path
shown on the map you'll see an annulus, i.e. a ring of Sun
surrounding the Moon. But there won't be a total eclipse from
anywhere because on May 20 the Moon will be farther away than
usual so it won't appear quite big enough to cover up the Sun.
Some places in the east bay are holding special events (and
have ideal viewing spots up in the Oakland/Berkeley hills).
http://www.chabotspace.org/calendar.htm?date=5-20-2012&p=143935
http://events.berkeley.edu/index.php/calendar/sn/lhs.html?event
Any other place from which you can see the Sun low in the sky in
the west will be good, as long as the weather is clear and you have
a way to view the eclipse (e.g., pinhole projector; see attachment).
Let's hope for clear skies.
TIPS FOR VIEWING THE PARTIAL SOLAR ECLIPSE ON MAY 20, 2012
(1) PINHOLE PROJECTOR
A really good way to view the eclipse is to make a pinhole
projector out of a cardboard box or a wide cardboard tube.
What you do is cut a hole in one side of the box and tape a piece
of aluminum foil over it. Then you poke a small hole in the foil
(e.g. with a safety pin). If you point this hole at the Sun
you'll get an image of the Sun on the opposite inside wall of
the box.
To view the image you need a way to look inside the box. One
way is to cut the flaps off and turn the box upside down over
your head. Just be sure NOT to look at the Sun through the pinhole!
You only want to look at the projected image of the Sun. Another
way is to cut a couple of viewing windows in the sides of the box.
You also might want to tape a piece of white paper on the inside
wall of the box where the image appears so it will be as bright
as possible.
It's best to start with big box, if possible (e.g. at least 30"
long in one dimension). The size of the image of the Sun will
be proportional to the size of the box (or tube). A 30" box
will produce an image about 6 mm (1/4 inch) across. A 60" box
will produce an image twice that size, etc.
I'd recommend making the box in advance and then trying it out
on the Sun ahead of time to get used to how to point it at the
Sun and where will appear, etc. Any day will do.
The exploratorium has some instructions (and pictures) about
how to use a mailing tube to make a pinhole projector (same
idea, but a little harder to point at the Sun than a box).
http://www.exploratorium.edu/eclipse/how.html
(If you scroll down to the bottom of the exploratorium's page,
you'll also find a "quick and easy" way to view it, which just
involves a couple of pieces of cardboard. This is worth trying,
but keep in mind that the image of the Sun won't be that bright,
so it can be a little hard to see in the glare of everything else--
that's the reason it's worth using a box or tube if you can.)
(2) ECLIPSE GLASSES
Another option is to get your hands on a pair of glasses
that are specially designed for viewing the Sun (regular
sunglasses are nowhere near dark enough!). The special
glasses block out more than 99.9% of the Sun's rays.
Here's a link to one place that sells them:
http://www.rainbowsymphonystore.com/eclipseshades.html
(3) SPECIAL EVENTS
Chabot Space and Science Center and Lawrence Hall of Science
are both holding events:
http://www.chabotspace.org/calendar.htm?date=5-20-2012&p=1439355
http://events.berkeley.edu/index.php/calendar/sn/lhs.html?event_ID=50856&date=2012-05-20
Enjoy
