By now I am sure everyone in the US knows there will be a total solar eclipse on Monday, August 21.
Most of the continental US will be able to see at least a partial eclipse (where the sun is only partially covered by the moon).
The path of totality runs from Oregon to South Carolina. This is where the sun will be completely blocked by the moon. The closer you are to the middle of this path, the longer the sun will be obscured. The maximum duration will be 2 minutes and 41 seconds.
NASA has a website that includes state-by-state maps of the eclipse paths as well as times and duration for the eclipse:
Eclipse Maps | Total Solar Eclipse 2017
SAFETY: DO NOT LOOK DIRECTLY AT THE SUN!
Yes, I know this is obvious. The sun emits ultraviolet rays that can cause damage to your retina. The retina does NOT have pain receptors, so damage can be done even if you feel no pain. Do not look at the sun without a filter! A filter specified as ISO 12312-2 is required for eye safety.
Another trick is to use a pinhole box or some other projection method to see the eclipse safely.
If you have binoculars or a telescope do NOT look through them with only eclipse glasses on! The filters for binoculars and telescopes should go at the front of the instrument, before the image is magnified. After magnification, the heat can burn through eclipse glasses or 'solar filters' that go on eyepieces. NEVER use a telescope solar filter that attaches to the eyepiece.
PROVISO: During totality and only during totality, it is safe to look directly at the eclipse. The sun's radiation is blocked by the moon at that time. You can even use telescopes and binoculars during totality. BUT be careful that you are not looking through them when totality ends! Know how long totality will be in your area and look away well before it ends.
Partial Eclipse: For those unlucky enough to not be in the path of totality, always use a solar filter to watch the eclipse. Any amount of the disk of the sun being visible is enough to cause eye damage!
Look for differences in shadows, especially from trees. The shadows will have crescents in them showing the extent of the eclipse.
During one partial eclipse I saw, there was a child of age about 10 who was shielding her eyes from looking into the sky during partiality. I asked her 'do you ever look directly at the sun normally?'. She answered 'no'. Then I said 'Then don't look directly at it today'.
Totality: The difference between a total eclipse and a partial eclipse is literally the difference between night and day.
As totality approaches, you might be able to see the shadow of the moon rushing towards you. Being on a hill helps with this. It moves quite fast.
Just before totality, look for shadow bands. These are quickly moving stripes of light and dark that flutter across the ground. They are caused by atmospheric effects on the last bit of light from the sun's edge.
Then look upwards for the 'diamond ring effect' and 'Baily's beads'. Both are due to bits of the sun disappearing behind the mountains on the moon.
During totality, the sky becomes dark and stars will come out. You should be able to see the planet Mercury (which is usually difficult to see because it is so close to the sun). The horizon will often still be lit up.
Again, this is when you can look directly. If you have binoculars or a telescope, look for prominences from the sun around the edges of the moon: they appear like small red flames.
Sunspot activity is low lately, so the corona (the sun's atmosphere) may well be smaller and dimmer than usual.
Finally, as totality ends, look for the diamond ring effect, Baily's beads, and the shadow bands again. Then watch the shadow of the moon race away from you.
Shadow bands - Wikipedia
Baily's beads - Wikipedia
Virtual Science Center
Solar eclipse - Wikipedia
Enjoy safely!
/E: I found this nice video of the eclipse path:
https://svs.gsfc.nasa.gov/4516
Most of the continental US will be able to see at least a partial eclipse (where the sun is only partially covered by the moon).
The path of totality runs from Oregon to South Carolina. This is where the sun will be completely blocked by the moon. The closer you are to the middle of this path, the longer the sun will be obscured. The maximum duration will be 2 minutes and 41 seconds.
NASA has a website that includes state-by-state maps of the eclipse paths as well as times and duration for the eclipse:
Eclipse Maps | Total Solar Eclipse 2017
SAFETY: DO NOT LOOK DIRECTLY AT THE SUN!
Yes, I know this is obvious. The sun emits ultraviolet rays that can cause damage to your retina. The retina does NOT have pain receptors, so damage can be done even if you feel no pain. Do not look at the sun without a filter! A filter specified as ISO 12312-2 is required for eye safety.
Another trick is to use a pinhole box or some other projection method to see the eclipse safely.
If you have binoculars or a telescope do NOT look through them with only eclipse glasses on! The filters for binoculars and telescopes should go at the front of the instrument, before the image is magnified. After magnification, the heat can burn through eclipse glasses or 'solar filters' that go on eyepieces. NEVER use a telescope solar filter that attaches to the eyepiece.
PROVISO: During totality and only during totality, it is safe to look directly at the eclipse. The sun's radiation is blocked by the moon at that time. You can even use telescopes and binoculars during totality. BUT be careful that you are not looking through them when totality ends! Know how long totality will be in your area and look away well before it ends.
Partial Eclipse: For those unlucky enough to not be in the path of totality, always use a solar filter to watch the eclipse. Any amount of the disk of the sun being visible is enough to cause eye damage!
Look for differences in shadows, especially from trees. The shadows will have crescents in them showing the extent of the eclipse.
During one partial eclipse I saw, there was a child of age about 10 who was shielding her eyes from looking into the sky during partiality. I asked her 'do you ever look directly at the sun normally?'. She answered 'no'. Then I said 'Then don't look directly at it today'.
Totality: The difference between a total eclipse and a partial eclipse is literally the difference between night and day.
As totality approaches, you might be able to see the shadow of the moon rushing towards you. Being on a hill helps with this. It moves quite fast.
Just before totality, look for shadow bands. These are quickly moving stripes of light and dark that flutter across the ground. They are caused by atmospheric effects on the last bit of light from the sun's edge.
Then look upwards for the 'diamond ring effect' and 'Baily's beads'. Both are due to bits of the sun disappearing behind the mountains on the moon.
During totality, the sky becomes dark and stars will come out. You should be able to see the planet Mercury (which is usually difficult to see because it is so close to the sun). The horizon will often still be lit up.
Again, this is when you can look directly. If you have binoculars or a telescope, look for prominences from the sun around the edges of the moon: they appear like small red flames.
Sunspot activity is low lately, so the corona (the sun's atmosphere) may well be smaller and dimmer than usual.
Finally, as totality ends, look for the diamond ring effect, Baily's beads, and the shadow bands again. Then watch the shadow of the moon race away from you.
Shadow bands - Wikipedia
Baily's beads - Wikipedia
Virtual Science Center
Solar eclipse - Wikipedia
Enjoy safely!
/E: I found this nice video of the eclipse path:
https://svs.gsfc.nasa.gov/4516
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