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Unmanned _ Chit Chat _ The North American Solar Eclipse, Aug. 21, 2017

Posted by: PDP8E Mar 27 2017, 12:33 AM

As all of you know, by now, there will be an amazing Total Solar Eclipse this summer in North America stretching from coast to coast, and basically from 10 AM to 2 PM local time, from west to east.
An estimated 75 million people will be less than a half day's drive away from totality.
My family and I will be in Missouri that day, prepared to zip east or west in case of inclement weather.
Do you plan on observing this event?

Posted by: nprev Mar 27 2017, 12:40 AM

My wife & I reserved a hotel room in eastern Oregon almost three years ago. wink.gif

Posted by: rogelio Mar 27 2017, 01:13 AM

…Consider that sunny eastern Oregon (east of the Cascades) will be the prime viewing choice for British Colombia, Alberta, Washington, Oregon, and California north of the Bay Area…an aggregate population of about 30 million…

…And that 5% (conservative...the social media frenzy about the eclipse has yet to kick in….) of the folks in those states and provinces are going to travel to the 200-mile long POT in eastern Oregon to see the eclipse…That’s 1-2 million folks in the POT (5,000-10,000 per linear mile) in an area with an infrastructure (gas stations, groceries) built for 1% of that number…

…and finally, that most will want to leave the second the eclipse is over…

(and don’t even THINK about dodging clouds east or west at the last minute…imagine the traffic)…

…Just sayin’...and yes, I know that a total eclipse should be number 1 on everyone's bucket list!

Posted by: charborob Mar 27 2017, 02:41 AM

I will be going to Kentucky. Apparently, not the best choice, weather-wise, but closest to our home in Québec City. I have a campsite reservation about 1 hour from POT.

Posted by: nprev Mar 27 2017, 03:40 AM

Even if the odds aren't great, it's worth the attempt. I chased a hole in the clouds for the 26 Feb 1979 eclipse in Montana, and was successful. The images are still seared in my memory, even though I of course used proper viewing safety precautions. smile.gif

Posted by: JRehling Mar 27 2017, 03:58 AM

I have a conflict that is such a tremendous example of Murphy's Law that I'm going to be apoplectic about this until the next total eclipse. I'll have to settle for seeing the 75% totality where I live.

My plan was to go to Oregon, but I considered Wyoming as a good choice as well.

I'd be quite frightened of the chances of clouds in the East. I have been in the Midwest for a partial solar eclipse and clouds made it a non-event.

I experienced a 90% totality event in 2012 and one surprise to me was how the subjective experience – if one looked anywhere but the Sun was that nothing was happening. The crescent shadows in leaves were noticeable and it even made the shadow of my ears look quite devilish, but a daytime world lit with 10% sunlight looks very much like a daytime world lit with 100% sunlight, thanks to the logarithmic nature of the perception of sensation intensity. That last 10% is where the magic happens.

Posted by: monty python Mar 27 2017, 06:02 AM

GREAT THREAD! I live in Iowa less than a days drive from path. The day before, I'll watch the weather and pre position outside the path so I can get room and gas etc. Then the next day, drive to the path, depending on the weather.
Even if it's cloudy it could still be cool. I'm thinking I'll wear an eye patch to have one eye dark adapted.

Posted by: Gladstoner Mar 27 2017, 06:09 AM

My house in Missouri just happens to lie in the southern part of totality (1m 47s). Not good enough. smile.gif

Plan A is to drive about 20 miles to a state park to set up near the center line.

Plan B is to drive to wherever the forecast calls for clear skies (there will be a cloud-free area somewhere between Oregon and South Carolina).

I've waited 30+ years to see this.... too long to wait just to be clouded out.

Posted by: Gladstoner Mar 27 2017, 06:13 AM

Fred Espenak's 2017 eclipse talk contains a wealth of practical information:

Posted by: fredk Mar 27 2017, 02:12 PM

QUOTE (monty python @ Mar 27 2017, 07:02 AM) *
Even if it's cloudy it could still be cool.

I can vouch for that. The one time I was in the path of totality it was cloudy. It was probably the coolest thing I've ever seen, with the entire landscape darkening so quickly. It's extremely rare to get to see real-time astronomical processes like that.

So on the day, if it's between a cloudy view from within the path of totality, and a drive to an area with a better forecast but where you might get stuck with x million others on a road outside the path, I'd suggest seriously considering the bird in the hand...

Anyway I too have been waiting ~30 years - I still recall leafing through a canon at a university library and seeing that date, 2017. I've got campground and hotels booked in the path in eastern Oregon with family...

Posted by: tasp Mar 27 2017, 02:23 PM

I saw the February 1979 eclipse from near Roundup, Montana. As I recall there were over 400 of us at the Huntley Lodge south of Bozeman, and the organizers set up an 'eclipse bus caravan'.

We were awakened VERY early the day of the eclipse, put on the buses, and the organizers attempted to maneuver the 'eclipse bus caravan' to a location where the clouds would be thinnest when the eclipse swept over the state.

The skies weren't completely clear, high thin cloud layer and a few lower clouds were visible, but in the opinion of the 'veteran' chasers, the clouds enhanced the aesthetics of the event.

There were some notables with us, mark Chartrand, Scott Carpenter and Frank Drake, among others. The eclipse tour ran for several days at the Huntley Lodge and there were many presentations on orbital inclination, ecliptic, Saros cycles,

penumbra, coronal observations, relativity etc, It was a wonderful experience. There were also helicopter rides available to tour nearby Yellowstone in winter, and while the views were spectacular, I discovered I didn't really care

for flying in a helicopter.

As for the eclipse itself, it was memorable, The clouds allowed us to see and perceive the motion of the approaching shadow of the moon, Bailey's Beads and the Diamond Ring were magnificent despite the thin overcast. IIRC, we had just o

2 minutes of totality, and then it was over. Most of us slept in the "Eclipse Bus Caravan' on the way back to the lodge despite the excitement of the eclipse, the early wakeup and the long bus ride were quite tiring .

The attendees were all great folks. I recall during the final meeting the night before the eclipse the organizers announcing that 1/2 of the buses would be designated for the cigarette smokers, and 1/2 for the non-smokers. There was a

humorous pause after the announcement as everyone in the crowd started looking around for ANY cigarette smokers. As it developed, there just weren't more than a small handful of smokers, so

no buses were designated for smokers.

I also recall the staff of the Huntley Lodge being overwhelmed with the crowd as, at the time, it was the first occasion the lodge was full.

I'd definitely recommend seeing the August eclipse, and if anyone is considering any of the organized tours, I'd give that a strong thumbs up too. Eclipse chasers are FUN PEOPLE !!

As for photographing the event, I did buy a better camera and the biggest telephoto lens I could afford, and I took a few pictures of the eclipse, but if I had a do over, I would skip it, everyone else had better equipment, and

my pics were a huge disappointment and a waste of valuable eclipse time.

I was unaware at the time we had Life Magazine contributors amongst the crowd, so a big surprise when the eclipse issue of Life came out and our observing site was pictured in the magazine.

Same issue also had some Voyager I Jupiter encounter too.

Posted by: volcanopele Mar 27 2017, 05:25 PM

My fiancee and I are getting married during totality north of Kansas City.

Posted by: Tom Dahl Mar 27 2017, 11:08 PM

My wife and I are planning to be in the Boise Idaho area for the eclipse. I've never seen a total solar eclipse (most was a ~80%-er about 1980 in Iowa), so I am very much looking forward to it!

Posted by: James Sorenson Mar 28 2017, 01:15 AM

I'll be camping and kayaking at Suttle Lake near central Oregon with family for a couple of day's prior, then driving up to hike one of the scenic trails around Mount Jefferson and Three Finger Jack to camp which is very close to the eclipse path the day before the eclipse.

Looking forward to it, it would be my first total solar eclipse!

Posted by: MahFL Mar 28 2017, 03:12 AM

My wife and I are driving up to Columbia, South Carolina ( 4 hour drive ) , we have a room booked.

Posted by: The Singing Badger Mar 28 2017, 04:03 AM

Flying out to Nashville! Probably a lousy choice weather-wise, but at least there should be a fun atmosphere in Music City.

Posted by: algorimancer Mar 28 2017, 05:40 PM

My wife & I are flying to Kansas City the night before, plan to stay in a hotel about 15 minutes south of the line of totality, then drive to the line for the show. Aiming for a really small town to avoid the crowds.

Posted by: Explorer1 Mar 28 2017, 06:18 PM

Regulus, Jupiter, and all the (other) inner planets will be quite visible:

For my part, I have a possible conflict, and if worst comes to worst I'll miss the best of it up here in Canada. Perhaps the 2024 one is another opportunity...

Posted by: stevesliva Aug 22 2017, 01:34 PM

Everyone make out well?

Totality goes over my house in 2024.... wink.gif

Which is to say, I moved out of the PNW too soon, but let's hope for high pressure in April 2024.

Posted by: Explorer1 Aug 22 2017, 02:12 PM

It was still a pretty impressive partial from Niagara Falls, and of course there will be a ringside seat in 2024 for me too.
Meanwhile, EPIC got some great views too:

Posted by: tasp Aug 22 2017, 04:09 PM

Viewed eclipse from ~20 miles SE of Broken Bow NE. 5 hour drive to get there was somewhat grueling.
I had planned route to get there to take predominately E-W roads instead of N-S thinking less traffic.

LOL, Nebraska is a big state, takes quite a bit of traffic to fill up their roads.

Left early, saw lightning behind and in front of me for first hour. As day passed and I traveled west, sky conditions steadily improved.

Arrived on site ~ 2 hours before first contact, which was a relief, although route I took to get there was deliberately
set so last 2 hours of trip was in totality area, JIC. Benefit of site was I had actual permission of landowner to be there.
Did not see too many eclipse chasers till I stopped in Loup City for leg stretch and to purchase a few items I forgot to bring
(mayo!). Pumps weren't too busy so fueled vehicle too. By mileage readout on vehicle, at that point had enough fuel to reach site and
get back home without having to stop again, JIC.

Site was an actual farm, dogs and chickens and sheep and cattle and quite a bit more. Fun, interesting place to stop.
Nice picnic table and shade tree to park under, and plenty of open yard to watch from. Also was informed by the farmer with
all the ducks and chickens and the rest of the fowl, very few bugs, and he was right.

Despite the lengthy wait for first contact, was glad to have allowed so much padding on schedule, JIC.

At first contact, we broke for lunch. My prior eclipse (2/26/1979) taught me first 2/3 of obscuration was like watching paint dry
(no offense, eclipse Gods) and I did check every 5 minutes. Lunch was nice out doors, farm cats were not too insistent about
getting a treat, and the other critters 'at liberty' (guineas, peahens, ducks, dogs, and some kind of decorative goat creature) left us alone.

The 'civilians' on the site marveled at the view through the eclipse goggles (I brought several extra pairs) as the moon covered a
substantial fraction of the sun and yet looking around the farm would not have tipped you off that anything unusual was going on.

I estimate around 80% coverage the contrast of our shadows on the ground started to pale away, and the farm wife noted the colors
'were off' on her flowers and buildings and car.

From 80% onward we all watched continuously and intently, the view of the sun becoming more and more compelling.

It was amazing though, even with the sun down to just the barest crescent, the sky was still blue and it was hardly darker to the west than it
was to the east.

Despite watching intently, I hardly noticed Bailey's Beads at all, the view seeming to go from the barest sliver of a crescent to Diamond Ring almost instantly.

And then it was TOTAL !!

Glasses came off and the grownups were quiet (one kid chattered annoyingly and off topic during the ENTIRE eclipse) and they marveled at the
surreal and alien appearance of their familiar sun.

The 'pointy' nature of the outermost corona elicited comments such as 'what's that', what is causing that' etc, and then we saw a few stars and planets
and that brought out a few comments too.

In the early stage of totality, I was looking for red/orange prominences but didn't see anything worth pointing out till the last 1/3 and then the trailing
edge steadily developed the color over a wider arc and everyone noticed it.

And then ZAP, Diamond Ring and I hollered "GLASSES!" and the main event was over.

Many comments about how from the latter stages of the obscuration how the heat had gone out of the sunlight despite it still looking bright
outside. Well, our eyes compensate for variable illumination, but the feel of warmth on your face from being full on to the sun is not compensated
for by our skin.

Right after the end of totality we noted the goats in the pen were all laying down, and the farm cats were all curled up on the driveway too. Didn't
notice much change from the fowl noises, there being squawks and calls during the entire event regardless. Maybe too many different kinds of
birds on site?

The yard light came on, and also a set of Christmas lights on a gazeebo structure they had.

Didn't watch too much of the latter part of the eclipse. We picked up all our stuff and headed home, taking care to execute a reciprocal course,
being amazed at the lack of traffic we encountered on the way there, and hoping for the same on the way back.

There was more traffic on the way back, but nothing enough to be an issue except at one rural intersection where left turns onto a busy
road were backing up traffic maybe 30-40 vehicles. We were thru in 5 minutes, and that was the only traffic issue all day.

Stopped for ice cream, toilet and clot walk in Columbus NE and then pressed for home, getting back well before dark.

Furthest license plate we noted was only Wisconsin, and not sure what to make of nearly all the others being Nebraska with a few South Dakotas mixed in.

Also, I have maligned Nebraska in the past for one of the dullest car rides I have suffered on Interstate 80 there. Fortunately yesterday we traversed far more
interesting terrain; hills, cows, trees, creeks and irrigators. Also, irrigation canals, had no idea such works existed in such quantity.

Had a great time, excellent experience, and still despite all the fun, glad to be home after a successful trip.

Posted by: JohnVV Aug 22 2017, 11:15 PM

here in the Metro Detroit Area it was partly rain cloudy , no rain
cnn and my sim were as good

a short youtube vid

a few screenshots

Posted by: Tom Dahl Aug 23 2017, 02:30 AM

My wife and I live in Massachusetts, and had been planning an Eclipse vacation to the western US for many months (should I say Moons). We settled on central Oregon, near the tiny town of Ashwood. We were on the site of a ranch and agate mining claim, happily paying the owners for the privilege of being completely safe and comfy on their property. We had been staying in Gresham OR (which is a few miles east of Portland) 152 miles away from that site, which was the closest reasonable lodging I could find 8 months ago. We left Gresham at 4:30 AM and reached the site a little before 7:00AM (totality was to occur at about 10:22 AM local time). During the drive we watched Venus and the constellation of Orion climb into the sky before sunrise. We passed many little pull-outs and larger parking lots along the road overflowing with cars and eclipse watchers, and a large rest area that was full of cars; a few US Army or National Guard troops were standing around the by-then blocked-off entrance along with Highway department staff.

While waiting at our site for first contact we explored the area and the small mining claim. There were a couple of dozen other cars scattered over a few acres of the property. Then we settled down to watch the sky show. The forecast was for clear sky, though thin high clouds crept overhead; thankfully these did not turn out to be any problem. It gradually grew cooler and cooler, despite the expected daily high of 90F. It also grew dimmer and dimmer very gradually. By the time totality neared, only a couple of minutes away, the air was very cool and I felt quite chilly in short pants and a short-sleeve shirt. During the final minute or so before totality the ground and surrounding countryside was visibly getting dimmer. Freaky feeling! About 30 seconds before the start of totality I could see Venus high overhead.

Then - totality. This was the first viewing of such a spectacle for me. Amazing, incredible, stunning! I've been interested in Astronomy since I was an adolescent 45 years ago, and have seen scads of photos of the fully-eclipsed Sun. But there it was! Photographs do not do it justice. We were seeing it live, up in the sky in front of us all. It was bigger that I was somehow expecting it to look with the naked eye, and the corona was definitely brighter that I expected. Just beautiful, a ring of wispy white plasma surrounding a black perfect circle. I took a few hand-held photos, having decided months ago not to fuss very much over photography (even though I'm also a keen amateur photographer). To my eye the corona looked close to the third of my photos, the one with the longest exposure. Venus was brilliant overhead. I did not think to look for Orion, though the thin cloud might have obscured it in any case. The upper edge of the Sun had bits of red - a few prominences - visible with the naked eye.

The approximately two minutes of totality went by very fast, and then the brilliant sparkle of the third-contact diamond ring flashed out, with the remaining corona still visible. A second or two later the tiny sliver of the crescent Sun was once again blinding. Here are three cropped photographs taken with a 200mm telephoto lens (on a Nikon D300 APC-format digital camera), along with a wide-angle shot that gives a good impression of what it looked like in person.

Posted by: tanjent Aug 25 2017, 06:06 AM

In Tanya Harrison's recent Planetary Society blog post
I don't understand the logic of the course chosen by the Alaska Airlines eclipse-watching flight.

Why cross the path of totality at right angles?
I don't know the exact speed of the umbra at the point of interception, but a jet airliner flying along the totality track could have greatly increased the duration of the eclipse from the viewpoint of the observers. If I had been planning the event I would probably have tried to follow the track most of the way back to Portland. Instead, the flight appears to have actually reduced the interval of totality by crossing the track perpendicularly at 500+ miles per hour. A more stationary surface ship would not have faced this additional constraint, although it might very likely have missed the whole event due to cloud cover.

Posted by: Explorer1 Aug 25 2017, 12:49 PM

They had to be able to see the sun from the windows on one side, and the only place with an angle low enough was the Pacific, and heading either North or South.


Posted by: Tom Tamlyn Aug 26 2017, 02:35 AM

The moon's shadow is fast. NASA research jets flying along the umbral path were expected to be able to stretch the observation time

By contrast, in 1973 a group of astronomers on a special Concorde flight that chased an unusually lengthy eclipse (7 minutes on the ground) were able to stay in totality for 74 minutes.

Vice published an about the flight (3/16/2016). According the article, no currently flying supersonic jet has the range to perform a comparable flight.

Posted by: PDP8E Aug 27 2017, 03:11 AM

My wife and I traveled to St Louis (from Boston MA) and stayed at the River City Resort, on the Mississippi River (6 miles inside the path of totality)

We (meaning me) had great and exhausting plans to scoot east or west in case of weather. But a month before totality I decided to stay put on the roof of the parking garage to make this the least stressful event it could be. Rain or shine we were staying put.The only traffic would be the elevator.

Totality there, would be 1 min 37 seconds. Good enough for our 'starter eclipse'. We watched Oregon and Wyoming on the weather channel; we were glued glued to the TV (and the south facing window)

Forty five minutes before totality (which was going to be 1:18pm local) we went to the roof of the garage (5 floors up). It was the size of a football field and could hold several hundred cars -- I counted about 30. I guess everybody else was on the road or had their own place picked out. It was 95 degrees and humid. We walked to the south end. Below, the Mississippi was a hundred yards to our left, a huge storm system was visible far to the north. The Sun was high and overhead in the south.

The weather cooperated. A few puffy clouds off to the left and right as we faced south. Glasses on and off as we checked the progress and looked over the 360 degree view.

The light got dimmer in the sense that things looked grayer -- a lack of contrast.
A few minutes before totality Venus was a brilliant beacon in the dull blue/gray sky about 30 degrees to the right of the sun/moon. We were looking through the shadow at Venus. The temperature was dropping

A large working boat on the river (a stationary dredge? It had been there for the last day or so) was darkening and all of a sudden all its lights came on. It looked like Christmas lights, dozens of reds, greens, whites, ... it was a beautiful sight.

Glasses back on, a thin sliver was dwindling in real time. I shot a quick peek behind me to see if there were the 'shadow bands' on the pavement - nothing.

I looked up and saw the inbound diamond ring. No bailey beads that I could see. It was cooler and I felt a breeze from the west

Then Bang! Totality! Dark sky! A spiky corona! The corona was a brilliant - yet detailed - a white that I have never seen before. After a short bit I looked at the horizon -- all the way around - it looked like a never ending sunset. It was noticeably cooler now.

Back to the Sun/Moon -- amazing - breathtaking
Hey wait! where's Jupiter? I scanned to the left (east) and finally picked it out (50 degrees away?) -- not as brilliant as Venus

Back to the sun. There was Mercury -- so tiny -- you really had to look for it.
I missed mars completely - We heard crickets chirping

Back to the Sun/Moon. I could see red prominence at 12:00 and 3:00

The whole Sun/Moon/Corona was bigger than I expected

Pictures do not - and will never do justice to the all-embracing scenes and senses of everything that was going on. You have to be there!

A few seconds later a brilliant diamond ring -- a few seconds more and it was too brilliant to look with out the glasses.

The sky to the west was brightening as if it was sunrise - the sky to the east was dark - the moon's shadow was cruising on to Illinois and beyond

It was emotional -- I knew it would be spectacular -- but the gut emotions were quite unexpected -- I had a tear on my cheek - and my voice was cracking as I spoke about what we just saw.

We lingered a while, looking at the scenes and people. we talked to almost everyone on the roof as we walked to the elevator -- they were all blown away.

We went back to the room and watched more eclipse coverage

We didn't take a single picture -- we were just there in the moment

It was one of the best events of my life

My wife wanted to know only one thing: when is the next one ...

April 2024 - Mexico to New Found land!

We are going to be somewhere in there...

Posted by: brellis Aug 27 2017, 10:39 AM

A friend took these pics from Nebraska, is curious what the informed description is for the red around the inside edges of the moon. My uneducated guess is they are related to Bailey's beads, i.e. sunlight peeking thru valleys. Any better explanations from the more educated folks here?


Posted by: fredk Aug 27 2017, 03:29 PM

Nice - I think the pinkish glow is the sun's - a layer just above the blindingly bright surface.

From eastern western Idaho the prominences (pink flames on the right side of that image) were easily visible by naked eye, which surprized me. I saw the right edge brighten momentarily before the diamond ring appeared, but didn't notice any pink colour.

Generally the eclipse caught me completely off guard. 45-odd years of reading about them, seeing thousands of pics and movies, and understanding the geometry and dynamics left me thinking I knew too well what to expect. I was wrong. You can know that the dynamic range of the diamond ring is something like a million to one, but seeing it was utterly shocking. Maybe the single most overwhelming sensation was of complete surprize at the utter bizarreness of the whole thing.

Posted by: Airbag Aug 28 2017, 05:40 PM

I saw it from Weiser (pronounced "Wheezer") in Western Idaho from the motel lawn. Hung out with some groups of veteran eclipse chasers (including one group from Japan); this was my third "total" attempt and second success. Weather was perfect; not a cloud in sight.

As an experiment, I set my digicam for manual exposure and exposed for pre-eclipse lighting, and continued to take pictures of the crowd leading up to totality. It is amazing how dark those photos become closer to totality and in contrast just how well the human eye/brain adjusts for the ever-decreasing lighting. If I get time (I took more than 3000 photos overall for this trip) i may post some here later.

Totality is indescribable. Best I can do is that suddenly the sky was all "wrong" but stunningly beautiful at the same time. It was fun hearing the loud cheer all around the town as totality started! Then after a few seconds everybody became quiet (stunned, I suspect) except for some call outs of the temperature drop (13F in the end), locations of prominences and time remaining etc. The big prominence at 3 o'clock was easily visible with the naked eye - amazing! (I had seen it the day before though a H-alpha filter telescope). I saw Venus and Mercury with the naked eye but missed Mars. I did not have a clear horizon and did not see the shadow approaching or departing.

Somebody had staked a white sheet on the ground and the shadow bands were clearly visible just after totality ended. I took a movie of that which came out well but is too big to post here. I also took a time lapse and a movie facing the crowd leading up and during totality, just for the reactions. I did not attempt real photography of the corona, preferring to stick with the Mk I eyeball for this oh too short (2 min 5 sec) event.

One of the eclipse chaser groups was also a wine tasting club from Phoenix, and when totality ended I heard the champagne corks popping! Headed out ASAP after totality ended as a long drive was ahead that day, but by avoiding highways there were only some delays getting out of the town and nowhere else.

Simply fantastic all around and Weiser put on a great multi-day eclipse festival.


[edit: Also someone had made a piece of cardboard with the letters "IDAHO" stamped out with small holes; made for neat sun image projections during the partial phases]

Posted by: JRehling Aug 28 2017, 07:31 PM

QUOTE (tanjent @ Aug 24 2017, 11:06 PM) *
Why cross the path of totality at right angles?

My guess is safety. The thousands of other planes in the sky can't all accommodate one doing something unique for a special occasion.

The regime that governs air travel to assure safety makes sure that no path crosses any other path in three dimensional space (except at airports). Deviating from that arrangement assumes a lot of extra risk, and is probably absolutely forbidden.

Posted by: JRehling Aug 28 2017, 07:35 PM

I had a conflict preventing me from going to the path of totality. As it is, this became the third significant partial eclipse I've seen in 5.5 years, and one more partial will occur in 2023.

I'm thinking about the 2019 eclipse in South America. Northern Chile is one of the sunniest places in the world (hence the observatories!). Totality will also pass just south of Buenos Aires.

I also, per my plan, decided to scan the classifieds for a solar telescope, figuring that a lot of surplus would hit the market after August 21. Without looking too hard, I got a $100 discount on a barely-used one. So I'll be looking at the un-eclipsed Sun a lot more in the future.

Posted by: tanjent Aug 30 2017, 03:02 AM

QUOTE (JRehling @ Aug 29 2017, 03:31 AM) *
My guess is safety. The thousands of other planes in the sky can't all accommodate one doing something unique for a special occasion.

The regime that governs air travel to assure safety makes sure that no path crosses any other path in three dimensional space (except at airports). Deviating from that arrangement assumes a lot of extra risk, and is probably absolutely forbidden.

For me JRehling's point here makes the actually-chosen course more difficult to understand, not easier. Most of the Asia-West Coast trans-oceanic traffic in that area is bound to be east-west, very much like the eclipse path, and the safest parallel non-intersecting course would be to go with the flow as much as possible, first flying westward to meet the oncoming shadow, and then returning east while trying to keep pace with it. By contrast, the polygonal path actually flown doesn't look like a simple solution to anybody's air traffic concerns.

The earlier points made by Explorer 1 and Tom Tamlyn are pretty persuasive on their own. The umbral spot should move at varying speeds depending on the angle formed by the earth's surface and the Sun-Moon-Earth line. Where the two are closest to perpendicular, somewhere around the middle of the track, the spot should slow to a theoretical minimum of about one hour per time zone, which might be about twice the speed of a passenger jet. Elsewhere it will move faster.

Posted by: mcaplinger Aug 30 2017, 04:19 AM

My best eclipse photo: rolleyes.gif Compare and contrast with

It would be fairly straightforward to colorize this with EPIC color (hint, hint) --

Posted by: mcaplinger Aug 30 2017, 04:29 AM

QUOTE (JRehling @ Aug 28 2017, 11:31 AM) *
The regime that governs air travel to assure safety makes sure that no path crosses any other path in three dimensional space (except at airports).

I don't think I follow what you're saying. Flights flying compass headings of 0 to 179 fly at odd multiples of 1000 feet MSL, headings 180 to 359 fly at even multiples. That insures minimum vertical separation. And then there are systems like TCAS to help planes avoid each other. I doubt if planning this eclipse flight was all that challenging from an ATC perspective.

FWIW, I saw a different commercial airliner fly almost across the sun west to east a minute or so before totality in Oregon but I doubt if any of the passengers could see very well on that heading. Nice for the pilots, though.

Posted by: fredk Aug 30 2017, 04:55 PM

From extreme western Idaho a plane was visible flying into the umbra. I caught this with a time lapse sequence - here are two frames, about 6 seconds apart, showing the contrail just before and just after second contact:

The earlier frame has the shorter exposure, yet the trail appears brighter in it, so it's clear that the contrail darkened substantially (my goal is to end up with a radiometrically calibrated time lapse).

With the sun in the SE at the time, the plane must've been flying roughly south to north. With an estimate of it's altitude there may be some hope in identifying the flight. But from the plane the sun would've been 45 degrees high and roughly 35 degrees to the right as viewed through the starboard windows. Probably a difficult observation with typical airline windows. But of course the darkening of the sky and landscape would've been obvious.

I'm sure there were more examples of this given how packed the US airspace is.

Posted by: Gladstoner Aug 30 2017, 05:04 PM

In west Kentucky, there were quite a few planes with contrails moving along the shadow path as totality approached. It was apparent that a number of flight paths were somewhat modified for the eclipse. A video capture just before totality:

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