Ecliptic Science!

[DeltaDizzy]

Ecliptic Science!

 

So I decided to make a science project related to the eclipse. Does barometric pressuer go down in an eclipse? I dont know. Is anyone else "doing science"(taking pics/vids) during the eclipse?

I will use a Raspberry Pi and Sense HAT to take barometric pressure measurements for 6 minutes. This will encompass all of totality. I will then take the resulting .csv file and turn it into a graph.

PSA:

Remember, when doing anything before or during the eclipse, do not look directly at the sun. The total phase is safe to look at, but the moment the sun starts to return, be sure to start using eye protection again. Unfortunately, partially obstructed disk isn't as painful to look at, but just as dangerous. Watching for 30 seconds can leave you blind, and even shorter exposure can lead to irreversible eye damage.

To see how the sun damages your eyes, see this scott manley video.

https://www.youtube.com/watch?v=aVDmEboPkOw

 

Special Thanks:

@Nertea for Python help and the solution in disguise.

@blowfish for python help

HackSI for the obvious solution.

Edited August 21, 2017 by DeltaDizzy

[Exploro]

I would be cautious about attempting to measure eclipse-induced changes to local barometric pressure. For starters the event itself is very brief; less than two or three minutes. While there might be a detectable changes in temperature that might not cause a significant change in local barometric pressure (or more to the point a detectable change). Furthermore; weather systems in your vicinity might actually be responsible for any changes in local barometric pressures you detect during your observations. As pressure systems, fronts, or upper levels troughs move with respect to a given location, the pressure also changes as a result. Thus an eclipse-induced change; if any, might be drowned out by the stronger effects of these weather systems; making it impossible to tell with absolute certainty that the changes you would observe throughout the time of the Moon's transit was actually produced by the Eclipse.

Edited August 21, 2017 by Exploro

[K^2]

I'm in the region that's going to get 75% cover. Was hoping to drive out to Oregon to be within totality, but my health betrayed me. So I'm planning to build a simple camera obscura today to watch the Sun safely as it gets partially blocked by the Moon.

As a public service reminder, do not look directly at the sun. Unfortunately, partially obstructed disk isn't as painful to look at, but just as dangerous. Watching for 30 seconds can leave you blind, and even shorter exposure can lead to irreversible eye damage.

Regular sun glasses will not protect your eyes sufficiently. Most will not block enough UV to completely protect you.

[DeltaDizzy]

58 minutes ago, K^2 said:

As a public service reminder, do not look directly at the sun. Unfortunately, partially obstructed disk isn't as painful to look at, but just as dangerous. Watching for 30 seconds can leave you blind, and even shorter exposure can lead to irreversible eye damage.

Is it OK if I put this in the OP?

59 minutes ago, Exploro said:

I would be cautious about attempting to measure eclipse-induces changes to local barometric pressure. For starters the event itself is very brief; less than two or three minutes. While there might be a detectable changes in temperature that might not cause a significant change in local barometric pressure (or more to the point a detectable change). Furthermore; weather systems in your vicinity might actually be responsible for any changes in local barometric pressures you detect during your observations. As pressure systems, fronts, or upper levels troughs move with respect to a given location, the pressure also changes as a result. Thus an eclipse-induced change; if any, might be drowned out by the stronger effects of these weather systems; making it impossible to tell with absolute certainty that the changes you would observe throughout the time of the Moon's transit was actually produced by the Eclipse.

The measurement interval will last 6 minutes, and a 6 minute dataset will be recorded before the eclipse starts,to be used as a control.

Edited August 21, 2017 by DeltaDizzy

[Scotius]

I experienced two partial eclipses so far - and i assure you, temperature will drop. It's actually kind of scary how much such brief event influences the environment - makes you appreciate Sun a lot more Also, you could pay attention to wind strenght and direction during the eclipse - if there will be noticeable drop in the atmospheric pressure, wind direction should change by nearly 180 degrees before and after the maximum. A simple compass and a wind flag should be enough to check it.

[K^2]

3 hours ago, DeltaDizzy said:

Is it OK if I put this in the OP?

Of course!

[Shpaget]

For those that don't have RPi, a cool Arduino based solution is PLX-DAC. Basically you feed the data into a Microsoft Excel spreadsheet and from there you do whatever you want with it.

https://medium.com/@islamnegm/quick-start-to-simple-daq-system-using-plx-daq-excel-arduino-d2457773384b

[ProtoJeb21]

@DeltaDizzy Cool project you're working on! I never really thought of the possibility of pressure drops during the eclipse. However, it does seem possible. The air within the path of totality will cool and sink, possibly raising barometric pressure. Also, that air will likely spread out of the Path of Totality and interact with much warmer air to possibly ignite thinderstorms. While I won't be doing any SCIENCE experiments during the eclipse, I will get as many images and videos as I can of the event.

[qzgy]

I'm in the same boat as ProtoJeb. No proper science but lots of pictures

[Green Baron]

Edit: i took the link that out, too much philosophy, too little data ...

found it by searching "atmospheric pressure solar eclipse"

Meteoroligal metrolo weather effects during solar eclipses is apparently not trivial ...

Edited August 21, 2017 by Green Baron

[DeltaDizzy]

eclipse time!

[sevenperforce]

16 hours ago, K^2 said:

Regular sun glasses will not protect your eyes sufficiently at all. Most All ordinary sunglasses will not block enough UV to completely protect you at all.

Fixed that for you.

To make it perfectly clear: regular sunglasses will do NOTHING to protect your eyes. Nothing whatsoever. In fact, they will make things worse, since your pupil will dilate wider and allow in more light. There are three ways to safely view the eclipse:

1. With the naked eye, during totality, as long as the corona is perfectly round and there's no crescent peeking around the edge.
2. With approved solar filter glasses that block 100% of high-energy light, 100% of infrared light, and 99.9% of visible light. If you have solar glasses, you can test whether they are "approved" by looking directly at an incandescent bulb from less than 6". If you see anything glowing other than the filament (this may include a slight reflection of the filament off the back of the inside of the bulb), they aren't real solar filter lenses.
3. With your back to the sun, using a pinhole camera that projects the image of the eclipse behind you onto a surface in front of you.

Unless you're doing one of the above three things, you WILL do permanent damage to your eyes. Worse than if you happened to glance at the sun on an ordinary day.

[DeltaDizzy]

Now partial, will upload pics later

[Bill Phil]

Ah, yes, the ecliptic plane!

https://en.m.wikipedia.org/wiki/Ecliptic

Oh, wait a minute...

[Brotoro]

I watched the total solar eclipse from near Mount Juliet, Tennessee, where the totality was 2 minutes 28 seconds. There were some cumulus clouds threatening an hour before totality, but these dissipated as the temperature dropped while the partial phases progressed. Totality was beautiful. I shot pictures for the first half of totality, and you can see a thin band of wispy clouds moving in as my photo sequence ends. But that band was too thin to spoil the view while I was looking at the second half of totality (mainly with binoculars). Regulus was just to the left of the Sun during totality (with Venus blazing further off to the right...Venus popped into view during the later part of the partial phases). 

There were some high cumulus clouds off to the west and east, and we could see those darken and lighten as the shadow approached and receded before and after totality. The birds were confused and all roosted in a big bunch on some power lines as totality approached.

I saw very faint shadow bands on the ground about a minute before totality, and strong shadow bands about a minute after the end of totality. They look like an effect you'd see by shining light through heat shimmers.

I can't post pictures now (I will be spending the next 11 hours sitting at airports or driving home).

Edited August 21, 2017 by Brotoro

[DeltaDizzy]

It almost got clouded out where I was.

[cubinator]

I would have done science, but it is such a quick event and a very special one so I just tried to take it all in as much as possible.

Edited August 22, 2017 by cubinator

[K^2]

10 hours ago, sevenperforce said:

To make it perfectly clear: regular sunglasses will do NOTHING to protect your eyes.

While I agree that this should be the base assumption for any pair of sunglasses, this statement is not technically true. Glass, real glass, is an excellent filter of the UV rays. This is why we've had such a thing as sunglasses long before we had fancy UV-blocking polymer coatings. And if you happen to have a pair of sunglasses made with thick, heavy glass lenses, they will give you significant protection from Sun's UV rays.

Sun happens to be bright enough that even with perfect UV filter, it will physically burn your retina, because it's exactly like putting a magnifying glass next to a sheet of paper. But amount of time it takes to cause permanent damage with and without UV filtering is substantial.

This by no means goes into category of, "Go ahead and look." Because it's still horrible for your eyes, and because you can't be certain what your shades are made out of despite what it says on the label, and you should never look at the sun through the shades. But if we are talking about academic truths, some glasses do make it less harmful.

[cubinator]

10 hours ago, K^2 said:

While I agree that this should be the base assumption for any pair of sunglasses, this statement is not technically true. Glass, real glass, is an excellent filter of the UV rays. This is why we've had such a thing as sunglasses long before we had fancy UV-blocking polymer coatings. And if you happen to have a pair of sunglasses made with thick, heavy glass lenses, This by no means goes into category of, "Go ahead and look." Because it's still horrible for your eyes, and because you can't be certain what your shades are made out of despite what it says on the label, and you should never look at the sun through the shades. But if we are talking about academic truths, some glasses do make it less harmful.

Yeah, if I'm gonna go ahead and look at the sun through some glass I'll make sure it's welders glass first.

Edited August 22, 2017 by cubinator

[NSEP]

I know im sort of late. But a few years ago, we had a partial eclipse in Europe. The news was overdramatisizing it alot, they said 'nature will stand still for a few minutes' (note that i was and lived in The Netherlands, there was going to be no full eclipse in that place anytime soon, yet the media where going crazy and acting like partial eclipses never exist) Yet i got to see was a banana sun and had no noticeable affect on the temperature or something. you could look straight at the Sun though, since there was a thick enough pack of clouds, not to make the sunlight too bright and not too dimm. 

For the next one, i will have to use my telescope and visor, to do "science". Likely not going to be a full one but its something.

[Shpaget]

So, I came across a flat Earther video in which a guy comments on the fact that the shadow of the Moon being cast on the surface of the Earth during eclipse travels from west to east. His main argument is that this is the proof of some conspiratorial trickery since Earth rotates once per day and it takes Moon to orbit the Earth roughly 28 days, hence the shadow can not possibly travel from west to east since Moon moves a lot slower that the Earth rotates. He then proceeds to demonstrate this by moving a golf ball in front of a rotating globe. In his experiment, the shadow really does move from east to west.

Of course, he neglects to take into account vast distances involved when dealing with anything space related, even our closest neighbor, the Moon. Since I am somewhat fascinated by those distances, I fired up Solidworks and drew our little Earth - Moon system to scale, and indicated the movement of Earth and moon one hour after noon. The view is from above the plane of ecliptic, looking down on North Pole. Earth and Moon rotate counter clockwise in this depiction.

The small circle on the right is our little planet Earth, the big dash - dotted circle that doesn't fit the image is the orbit of Moon (which is aproximated to be circular 380 000 km radius from the center of Earth), and the two tiny circles on the left are Moon, one representing its position at noon and the other one hour after noon. The Sun, of course, is waaay to the left off screen (more than 100 meters at this scale) and assumed to cast perfectly horizontal rays.

Here we see the left detail with the angular displacement that occurs after one hour (fun but unrelated fact, it's just over one Moon diameter):

,

And here we see the resulting motion of the shadow in relation to the Earth's one hour worth of rotation (15° mark):

The center of the shadow at noon is the topmost gray line, while the bottom blue line is the path of the shadow one hour later. It's clear that the Earth's rotation can't keep up with the shadow.

I know you guys don't need convincing, but I find these sort of images very simple yet powerful and fairly accurate tools to represent just what happens in the skies above.

[YNM]

On a vaguely-related note, I just realized something : the moon doesn't travel in a straight line wrt the sun. I actually only noticed it when I'm ogling timeanddate.com 's animation of eclipses. I'm well aware that most direct straight-path approximation will result in 2m worth of eclipse ; but I always wonder why and how the longest eclipse reaches 7m. I think I finally knows why.

Also, on the whole movement of shadow thing, I could only imagine that the correct way to interpret it is to see the Sun-Earth as being stationary; this'd mean the moon is moving from "west side" (sunrise side) of the Earth to the "east side" (sunset side). The shadow would move even faster than that.

[Shpaget]

3 minutes ago, YNM said:

Also, on the whole movement of shadow thing, I could only imagine that the correct way to interpret it is to see the Sun-Earth as being stationary; this'd mean the moon is moving from "west side" (sunrise side) of the Earth to the "east side" (sunset side). The shadow would move even faster than that.

That's the assumption I embraced with the model above. After all, during the one and a half hour that it took the shadow to cross the States, the Earth moved only 360/365/24*1,5 = 0,06 degrees. Compared to 15° of planetary rotation, it's negligible.