You are living the life that people actually want to become engineers for: changing lives, letting people see something from another perspective (in this case, literally) and inspiring the next generation. Everytime I come to your channel to see a new video, I never leave disappointed or uninterested.
Great job Grady. To improve image contrast you can spray the inside of your funnel matt black. This reduces internal reflection of light scattered back from the projection screen being reflected around the tube and lightening up the darker areas of the projected image. Should make sun spots stand out much more clearly.
Like you, I will also be SLIGHTLY out of the path of totality. We'll only be seeing 99.9% of the eclipse. I will also be at the elementary school where I teach science. I can't just abandon 400 kids to get a better view. Our school has a device called a SunSpotter which works a lot like what you've built. When you get it lined up, it projects a larger and dimmer image of the sun onto a white stage that is part of the device. I've used it over the years to show kids sunspots and to demonstrate the slow rotation of the Earth (as the sun visably moves over the plate), but it'll be an interesting and safe way for us to view our (almost) total eclipse. Meanwhile, I'm already making plans to be in totality when the April, 2024 eclipse crosses the US. I'm not going to miss that one!
I drove from SW Texas to Nebraska to see that one in 2017, but I can watch the 2024 eclipse from my own home, which will be in the center of totality! Just six months earlier, we've got an annular eclipse with the path of annularity about an hour's drive away. Exciting times!
At the last eclipse I built myself a camera obscura from our office pantry because a) I was at work, b) I don't have neither a telescope nor c) those special sun glasses (I forgot where I put them after the eclipse of 1999). I covered the whole window with paper to get it dark inside and punched a hole with a pin in it. I just had to hold a screen into the light beam. But you need at least card board to get it really dark. Otherwise the tiny amount of light getting through the pin hole does not make a clear picture. If the hole is too big the picture is blurry (out of focus).
That's so funny, I happened to try this for my own for the first time just this afternoon! It worked great and I saw those exact sunspots as are in the video
Like why does antenna length matter? why are radio masts so high? and whats actually on a radio mast? How many watts does a radio tower use to power its transmitter. are there different types?
My son and I set up a pinhole camera affixed at a specific height over our backyard picnic table, and aimed to shine down at a paper tablet. During the actual event, every five minutes, he documented the time and the shape the pinhole camera cast upon the page. Not only did we effectively document the progression of the eclipse itself, but also the path of the light's trajectory as the earth rotated. We turned the resulting documentation into a flip-book. Quite an entertaining afternoon with the kiddo.
just made one! it's amazing! one note, though, we found it was much easier to use a rubber band to hold the screen on the end of the funnel than a hose clamp (we used shower curtain liner as the screen material). anyway, what a cool project! thanks!
you should really paint the inside of the cone black. to prevent the internal back reflection from the screen that then saturates the borders of the screen. painting it black will make it so you can see more details that back reflection previously prevented up from showing
It's possible to use an overhead projector in reverse and project a very nice (small, but sharp) image onto the surface where the plastic slides usually are. Colleagues of mine did that at our research institute for a partial solar eclipse on the 20th of March 2015 (Europe). It wasn't for research purposes, we aren't astronomers. It was just there for everybody to see, which was cool!
We certainly did. We were in the path of totality in Northern Idaho. The weather was beautiful. We got our eclipse glasses, lawn chairs, drinks, and then sat back and enjoyed the show. Too bad these don't happen more often.
I think you should incorporate a mirror to flip the projection ~90°. In San Antonio the sun is going to be at 70° elevation at max obscuration, so you'll basically be lying underneath the telescope with the current arrangement.
I live in the path of totally, in the single best place to be (according to multiple news sources but still). It would be so great to see if I WASN'T LEAVING FOR COLLEGE THE DAY BEFORE!
Practical Engineering I love San Antonio, but while you are there you need to get Rudy's Barbeque it's over on sea world's side of town and I found it a couple years ago when I visited San Antonio.
I went with some of my family all the way to Anna, Illinois from Houston, Texas to be in the path of totality. It was worth the drive "There and Back Again" (An Eclipse Tale). Can't wait for 2024 so I can see the path of totality closer to home in or near San Antonio or Austin, Tx.
I'm excited. My house is in the center of the path of totality for that one, and there's an annular eclipse six month earlier in which the path of annularity will be an hour's drive away.
Yes, though it will be a very small projection if you don't use a very long tube. A 4' tube with a pinhole will get you a projection about the size of a pea.
I made a doohickey based on Cody's design. Mine has a focal length (distance from pinhole to screen) of about 30 inches, and the magnified image is still pretty tiny. It will work well enough to view an eclipse, but I wouldn't want to use it to view say, the transit of mercury. I'm in the path of totality for the 2024 eclipse though, and plan to set up a telescope as a solar projector. It's kind of too late for me to set one up now (I don't currently own a telescope). In all honesty though, Cody's pinhole viewer does have some potentially serious drawbacks. You have to essentially look through it like a telescope, which means pointing your face right at the sun. I very nearly blinded myself with sun glare while testing it out. Putting the magnifying lens on the other side of the screen, and then looking at the screen like you would a more traditional pinhole viewer might be safer.
Hey, thanks for the inspiration, I managed to gobble together a similar contraption thanks to that and actually get a fuzzy phone picture of a sunspot. Oh, by the way, it's a murder to keep the damn contraption steady without a tripod.
I don't know at what angle the sun will be in the US during the eclipse, but if it's high, a good way to make it even easier to watch is to point the telescope DOWN at a mirror on the ground so you don't need to bend down to look at the screen. Alternatively put a mirror down to view the screen.
I'm surprised this worked---the ray diagrams you have are not right; the telescope eyepiece is set up to produce a virtual image either at infinity away or some finite distance away, when adjusted for near-sighted people, which means outgoing rays are either parallel or diverging. I'll admit Sun being a pretty bright light source, you might still see something recognizable with an imperfect optical arrangement (we all saw the partial-eclipse shadows through tree leaves), but a lot of resolution is being left on table, if you are just using a regular telescope arrangement.
I was thinking about this question already having a mathematical answer, but did you notice any major correlation between the amount of time that had passed and how much you had to move your telescope to track it? For instance, X minutes elapsed time equated to re-position your telescope Y degrees? I'd be curious to see what the full mathematical answer is taking into account the orbits and rotation of the earth.
I think you might want to experiment with diffrent materials for the screen. The current one has that slight texture that gets in the way of the projection just a little bit.
It's the secondary mirror that gets cooked. If you've ever seen a parabolic mirror be used as a solar death ray, that's basically what happens to your secondary mirror. A refracting telescope is much better at handling unfiltered sunlight than a reflecting telescope. Though the lenses will get hot and potentially melt their housings.
I just observed it with a pinhole projector it was nice I helped some other people with theirs some of them didn't know what I was doing so I showed them what it does.
You promised me explosions !!!. You can also use a pinhole right and project it onto some paper ? Also you would be better with a light grey screen it will improve contrast .
just stack 15 bino viewers on there (each in each of the eye pieces of the previous layer) to get 30 effective eye pieces while reducing light levels by half each layer. (of course this is completely impractical and does not account for how it would effect focal length/ focus-ability... but hey... could be funny.)
Was in Kentucky during the event & was 6 miles from the center of it's path. The day before no dove were to be found flying. Only cicadas & frogs were sounding off before the eclipse. The second the moon began to cover the sun... both the cicadas & frogs were dead silent. Also the 3 to 4 mile per hour breeze drew dead still as well. Several fresh dead cicadas were found after the event & the breeze continued to blow once again. The country folk among us were concerned that their chickens might go to roost during it. The bee box we had set a go pro up at revealed the bees return at the beginning of the eclipse & departed it minutes after as well. 9317
I have a fresnel lens about the size of a piece of paper that I got from a dollar store, if I point it the right way will it expand the picture onto the ground?
Mícheál Hartman it's too late now, but baader planetarium make great "white light" filters, and thousand oaks makes nice filter material that's quite a bit sturdier
I had a chance to use an early 20th century historical telescope in Istanbul University. It was a huge telescope and they were still traditionally do old school style observations sometimes. We were putting a paper just like the funnel it hat some extent apparatus. And we were adjusting the paper to calibrate sun into a circle drawn on the paper. When oriented perfectly we were drawing the sun spots with a pencil. In a few days of recorded "sun papers" we could have seen the evolution of the sun spots and the rotation of the sun. When you put your hand between the ocular and the paper it was like a hot beam. You can see a photo of someone doing it here; gozlemevi.istanbul.edu.tr/?p=6450
Pretty much nobody who has had any education believed that in about 2000 years, the circumference of the earth has first been calculated (quite accurately) in 240 BC by the greek mathematician Eratosthenes: en.wikipedia.org/wiki/Eratosthenes#Measurement_of_the_Earth.27s_circumference