# Solar eclipses: partial vs totality **URL:** \ **Category:** Factual Questions\ **Created:** [March 20, 2017, 5:55am UTC](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593 "2017-03-20T05:55:32Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Flyer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/flyer/32/7298_2.png) [@Flyer](https://boards.straightdope.com/u/Flyer)\ **Post date:** [March 20, 2017, 7:51pm UTC](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593/21 "2017-03-20T19:51:14Z")
There’s some good information here. Thanks for the responses–even though some of the posters seem to be wealthy enough that they don’t have to worry about things like jobs, motel bills, etc. It’s all well and good to say “Go!” but a lot of us have jobs that don’t necessarily let us take time off any time we feel like it. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [March 20, 2017, 8:01pm UTC](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593/22 "2017-03-20T20:01:16Z")
> [@Flyer](#): > > There’s some good information here. Thanks for the responses–even though some of the posters seem to be wealthy enough that they don’t have to worry about things like jobs, motel bills, etc. It’s all well and good to say “Go!” but a lot of us have jobs that don’t necessarily let us take time off any time we feel like it. If you don’t have a motel reservation yet … then you don’t have to worry about getting one … they may well be already full … the challenge will be finding a place to park along side any and all public roads … all the roads were bumper-to-bumper with parked cars _the day before_ the eclipse in 1979 … in spite the fact _it was fucking raining_ … ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [March 20, 2017, 8:13pm UTC](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593/23 "2017-03-20T20:13:55Z")
ETA: I recommend at the highest levels to include some mobility in your eclipse plans … east of the Rockies they may be areas of pop-up thunderstorms … there’s no guaranty of sunny weather in August … keep a sharp watch on the weather forecasts in the days leading up and be ready to change locations at sunrise … ---
**Author:** ![wolfpup](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wolfpup/32/10618_2.png) [@wolfpup](https://boards.straightdope.com/u/wolfpup)\ **Post date:** [March 20, 2017, 9:29pm UTC](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593/24 "2017-03-20T21:29:37Z")
> [@watchwolf49](#): > > \ It starts in the Pacific, crosses into Oregon and across the USA, exits South Carolina and finishes out in the Atlantic \ Yes, thanks for correcting my thoughtless goof. :smack: This is because the moon orbits from west to east, and its shadow tracks its orbital speed which is roughly twice as fast as the earth’s rotational surface motion at the equator. Netting out the two speeds at the general latitude at which the eclipse shadow crosses the US, in case anyone is interested, according to my rough calculations the shadow will be moving west to east at approximately 1800 mph. ---
**Author:** ![Mtgman](https://avatars.discourse-cdn.com/v4/letter/m/b5a626/32.png) [@Mtgman](https://boards.straightdope.com/u/Mtgman)\ **Post date:** [March 20, 2017, 10:02pm UTC](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593/25 "2017-03-20T22:02:11Z")
We’ve got our RV rental reserved and campsite in Yellowstone confirmed. We’ll be in the Grand Tetons and Yellowstone area for the week leading up to the eclipse and plan to see it from whatever mountaintop we can get to in the Grand Tetons. Grand Tetons are expecting over a million visitors for the eclipse this year. We’ll be closely monitoring weather and ready to bug to an alternate viewing site if necessary, but we’re super excited for the trip. First time seeing a total eclipse for the whole totality and we should be directly under the maximum umbra. Enjoy, Steven ---
**Author:** ![Scougs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/scougs/32/3158_2.png) [@Scougs](https://boards.straightdope.com/u/Scougs)\ **Post date:** [March 20, 2017, 10:15pm UTC](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593/26 "2017-03-20T22:15:33Z")
I’ve been saving for 15 years for this. Going on an organised tour based out of Nashville. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [March 20, 2017, 11:07pm UTC](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593/27 "2017-03-20T23:07:18Z")
> [@Scougs](#): > > I’ve been saving for 15 years for this. Going on an organised tour based out of Nashville. I’ve been “planning on it” since I learned about it’s approach when I was in primary school in the early 1980s. So literally something like 35 years. (I’m in South Carolina–I’ll need to plan on traveling from my living room to my yard.) BTW, in Robert J. Sawyer’s book _Illegal Alien_, there is a character that argues that there is little reason for aliens to travel to Earth–after all, any resources we have would be much easier to acquire “at home.” Except the coincidence in apparent size between the Earth’s moon and the sun being so close as to allow such “fitted” eclipses has to be a very rare circumstance, so if anybody comes to Earth, they will be tourists looking to view eclipses. So if you want to find aliens, go to eclipse zones and look for closed off vehicles with darkened windows who never steps outside. ---
**Author:** ![DSYoungEsq](https://avatars.discourse-cdn.com/v4/letter/d/c6cbf5/32.png) [@DSYoungEsq](https://boards.straightdope.com/u/DSYoungEsq)\ **Post date:** [March 20, 2017, 11:40pm UTC](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593/28 "2017-03-20T23:40:41Z")
> [@wolfpup](#): > > Yes, thanks for correcting my thoughtless goof. :smack: This is because the moon orbits from west to east, and its shadow tracks its orbital speed which is roughly twice as fast as the earth’s rotational surface motion at the equator. Netting out the two speeds at the general latitude at which the eclipse shadow crosses the US, in case anyone is interested, according to my rough calculations the shadow will be moving west to east at approximately 1800 mph. Shadow will be traveling at roughly 2700 mph. 10 min. to cross Oregon, I recall reading. :eek: ---
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [March 21, 2017, 12:02am UTC](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593/29 "2017-03-21T00:02:31Z")
So The Flash could see it for longer than two minutes? ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [March 21, 2017, 12:11am UTC](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593/30 "2017-03-21T00:11:45Z")
> [@markn\_1](#): > > So The Flash could see it for longer than two minutes? I dunno, but the [Concorde certainly could](https://motherboard.vice.com/en_us/article/the-concorde-and-the-longest-solar-eclipse). ---
**Author:** ![wolfpup](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wolfpup/32/10618_2.png) [@wolfpup](https://boards.straightdope.com/u/wolfpup)\ **Post date:** [March 21, 2017, 1:08am UTC](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593/31 "2017-03-21T01:08:11Z")
> [@DSYoungEsq](#): > > Shadow will be traveling at roughly 2700 mph. > > 10 min. to cross Oregon, I recall reading. :eek: 10 minutes seems about right, but for me it seems to work out to about 2200 mph at that point. Of course one difference is that before I arbitrarily calculated the average over a distance between the coast of Oregon and several hundred miles out in the Atlantic over an elapsed time of 2 hours 32 minutes to get the estimated average speed. It turns out that the shadow speed is crazy variable – see [Table 1 in this paper](http://adsabs.harvard.edu/full/2011JBAA..121..105C) for just how wildly variable it can be. So I get a higher speed when just looking at Oregon, but I get 2200 mph at that point – still not 2700. 2700 mph seems a little high as it would cross the state in less than 10 minutes. For anyone interested, that last approximation was based on: Start point just inland of the Oregon coast, 44.7088N 123.728W totality at 17:17:16 UTC End point at the Oregon border 44.3328N 117.0483W, 17:26:15 UTC Distance 330 miles in approximately 9 minutes, which works out to 2200 mph. I also did another estimate over a similarly short distance down in the Atlantic far off the coast of South Carolina and got 1772 mph. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [March 21, 2017, 1:25am UTC](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593/32 "2017-03-21T01:25:29Z")
> [@wolfpup](#): > > [snip] … End point at the Oregon border 44.3328N 117.0483W, 17:26:15 UTC … [snap] This is a rock that butts out into the Snake River … good little catfishing hole right there … I think that’s where my middle son caught his first fish … if you’re in the area, ask in the Steamliner about me … I’ll be around there someplace … ---
**Author:** ![nearwildheaven](https://avatars.discourse-cdn.com/v4/letter/n/90db22/32.png) [@nearwildheaven](https://boards.straightdope.com/u/nearwildheaven)\ **Post date:** [March 21, 2017, 4:48am UTC](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593/33 "2017-03-21T04:48:47Z")
> [@beowulff](#): > > I don’t know if that’s a joke, but the eclipse is August 21st. Oops, sorry. Got my year and date mixed up, KWIM? :o You just know that there are oodles of cruise ships that are planning to be in the total zone on the coasts as well. ---
**Author:** ![Bullitt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bullitt/32/5725_2.png) [@Bullitt](https://boards.straightdope.com/u/Bullitt)\ **Post date:** [March 21, 2017, 7:47am UTC](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593/34 "2017-03-21T07:47:56Z")
> [@Flyer](#): > > There’s some good information here. Thanks for the responses–even though some of the posters seem to be wealthy enough that they don’t have to worry about things like jobs, motel bills, etc. It’s all well and good to say “Go!” but a lot of us have jobs that don’t necessarily let us take time off any time we feel like it. At least order your eclipse glasses early. Inexpensive, less than $1: > **[Solar Eclipse Glasses | We Ship Worldwide | Rainbow Symphony](https://www.rainbowsymphony.com/collections/eclipse-glasses-safe-solar-viewers?rfsn=461623.92701)** > > View incredible celestial events safely and clearly with our CE and ISO certified solar eclipse glasses. Shop eclipse glasses and viewers at Rainbow Symphony! > **[Eclipse ‎Glasses Stock | Plastic Eclipse Glasses](https://www.eclipseglasses.com/collections/eclipse-glasses-stock)** > > Don't miss out on the next solar eclipse! Our safe solar eclipse glasses are in stock and ready to ship for direct solar viewing and are a must-have for eclipse enthusiasts. Even a partial eclipse would be fun to watch, directly and safely with the certified glasses. ---
**Author:** ![Bullitt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bullitt/32/5725_2.png) [@Bullitt](https://boards.straightdope.com/u/Bullitt)\ **Post date:** [March 21, 2017, 7:53am UTC](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593/35 "2017-03-21T07:53:35Z")
> [@nearwildheaven](#): > > Here’s the official website, complete with a map. > > [NASA - Total Solar Eclipse of 2017 Aug 21](https://eclipse.gsfc.nasa.gov/SEgoogle/SEgoogle2001/SE2017Aug21Tgoogle.html) Astronomer Xavier Jubier has a better map, here: [USA - 2017 August 21 Total Solar Eclipse - Interactive Google Map - Xavier Jubier](http://xjubier.free.fr/en/site_pages/solar_eclipses/TSE_2017_GoogleMapFull.html). Jubier is the inventor of these maps and they have been copied by many others (as per [here](https://en.m.wikipedia.org/wiki/Talk:Solar_eclipse_of_August_21,_2017)). ---
**Author:** ![VOW](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/vow/32/3043_2.png) [@VOW](https://boards.straightdope.com/u/VOW)\ **Post date:** [March 21, 2017, 12:42pm UTC](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593/36 "2017-03-21T12:42:25Z")
Hundred and I have had our hotel reservation in Casper Wyoming for over a year now! ~VOW ---
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [March 21, 2017, 3:58pm UTC](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593/37 "2017-03-21T15:58:52Z")
> [@Bullitt](#): > > At least order your eclipse glasses early. Inexpensive, less than $1: I don’t trust those cheap glasses with mylar lenses. I’ve read that they can get scratched or damaged, leaving tiny lines or pinpoints where light can pass through unimpeded. It’s better to use welding goggles with #14 glass lenses (it’s IMPORTANT that the lenses are #14; many goggles come with lighter lenses, which you need to replace with #14). The total package may come to about $10 instead of $1, but if you value your eyesight, it’s worth it. If you do use the mylar glasses, be very careful while handling and storing them to make sure they don’t get scratched. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [March 22, 2017, 10:57am UTC](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593/38 "2017-03-22T10:57:50Z")
> [@Bullitt](#): > > Astronomer Xavier Jubier has a better map, here: [USA - 2017 August 21 Total Solar Eclipse - Interactive Google Map - Xavier Jubier](http://xjubier.free.fr/en/site_pages/solar_eclipses/TSE_2017_GoogleMapFull.html). Thanks, excellent map. Turns out that I’m almost exactly 10 km from the center of the path of totality. ---
**Author:** ![RealityChuck](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/realitychuck/32/195_2.png) [@RealityChuck](https://boards.straightdope.com/u/RealityChuck)\ **Post date:** [March 22, 2017, 11:24am UTC](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593/39 "2017-03-22T11:24:15Z")
> [@Bullitt](#): > > At least order your eclipse glasses early. Inexpensive, less than $1: > > [Solar Eclipse Glasses | We Ship Worldwide | Rainbow Symphony](https://www.rainbowsymphonystore.com/collections/eclipse-glasses-safe-solar-viewers?rfsn=461623.92701) > > [Eclipse ‎Glasses Stock | Plastic Eclipse Glasses](https://www.eclipseglasses.com/collections/eclipse-glasses-stock) > > Even a partial eclipse would be fun to watch, directly and safely with the certified glasses. The cheapest​ (safe) way to view a partial eclipse is to take two pieces of stuff paper, put a pinhole in one, and focus the light on the other. ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [March 22, 2017, 12:01pm UTC](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593/40 "2017-03-22T12:01:22Z")
Yep, even a 99% eclipse is still only 0.00000000000099% as interesting as a total eclipse. You could sit through an 80% eclipse and not notice anything, if you didn’t know it was coming. Make the effort. I’ve seen three and they are WELL worth the effort. Unfortunately I can;t get over to the US for this year’s, but I have a date in my diary for sunset on [August 12 2026](https://eclipse.gsfc.nasa.gov/SEplot/SEplot2001/SE2026Aug12T.GIF) on the west coast of Ibiza… now that really will be worth the effort! [Previous page](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593.md?page=1) [Next page](https://boards.straightdope.com/t/solar-eclipses-partial-vs-totality/782593.md?page=3)