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The most accurate map for August 21’s total solar eclipse

nasaviz.gsfc.nasa.gov

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Re: The most accurate map for August 21’s total solar eclipse

#41

Post by Dave_Rosenthal »

jessriedel wrote: post #32

Can someone explain why the claimed shadow of the moon is vastly more bumpy than it ever appears in the night sky? Or how to square this with the fact that altitude of the highest and lowest points on the Moon differ by less than 20km, or less than 1% of the diameter? The shadow looks like it has bumps of about 5-10% of the diameter.

The diameter of the path of totality is only about 100 miles, because it's only the umbra of the shadow. This is 20x smaller than the moon diameter. But, a 1km moon bump is a 1km bump on the umbra as well, magnifying it's effect by the mentioned 20x and leading to a much different appearance.

Re: The most accurate map for August 21’s total solar eclipse

#43

Post by leblancfg »

dekhn wrote: post #12
leblancfg wrote: post #7

Would love to hear how they generated the shadow contours from the Moon to the Earth's surface!

it's projection geometry. You create a geometry object with the earth's surface shape. Another with the moon's surface shape. Then, a light source that emits from a sun's shape. All objects are placed at the appropriate distances, and made to rotate and translate through space according to normal orbits. Then, you project the light from the sun onto the earth, with the moon in-between. This creates the 2D shape on th…

Thanks dehhn. From the LRO picture in the article, you can see that they're actually taking high-precision elevation maps of both the Moon and Earth into consideration, which sounds like something rather computationally intensive. I might be wrong, but I don't think they used Blender to handle that.

I would be curious to hear what tool they actually use, their pipeline, etc.

Re: The most accurate map for August 21’s total solar eclipse

#44

Post by matthewmcg »

spcelzrd wrote: post #42

My first thought: how will this affect traffic. I've been in Atlanta too long.

Me too.

We were going to make a weekend trip out of this. But we realized the chances of bad weather are pretty high at our planned viewing site in Western North Carolina and that it would be better to stay in Atlanta closer to an Interstate Highway so we can quickly drive to an alternate site.

Re: The most accurate map for August 21’s total solar eclipse

#47

Post by digitalsushi »

wyldfire wrote: post #2

I heard from a co-worker who plans to travel to Oregon that some of the hotel rooms in the path of the umbra are sometimes > 2-3k USD for the night(s) prior to the eclipse.

We're some New Hampshire tech bumpkins who got a hotel in Charleston SC for 15% of that. We're going to leave our phones and cameras inside, and just hang out by the pool with some cold beverages and experience the eclipse as it unfurls. Granted, it's not quite in the center, but I think it should be close enough to make the trip worth making. I suppose in a panic, we could drive about 40 miles north. Should we?

Re: The most accurate map for August 21’s total solar eclipse

#49

Post by cjensen »

corpMaverick wrote: post #45

When was the last time an eclipse like this happened in the US ?

It depends what you mean by "like this."

The last US West Coast to US East Coast eclipse was 1918.

The last time the totality was entirely within the current US borders and never over land elsewhere was 1257.

https://en.wikipedia.org/wiki/Solar_eclipse_of_August_21,_20...

Re: The most accurate map for August 21’s total solar eclipse

#50

Post by joezydeco »

pcl wrote: post #38
gagabity wrote: post #29

What about the rest of the world!!

This eclipse will only be visible in totality within the US. Here's a broader-scale map: http://xjubier.free.fr/en/site_pages/solar_eclipses/TSE_2017...

This map is way more useful than NASA's. Highly recommended.
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