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As someone who's paranoid about missing the eclipse due to cloudy weather, I've been working with a few people to launch a high altitude balloon during the ecli

by scd31 2y ago

As someone who's paranoid about missing the eclipse due to cloudy weather, I've been working with a few people to launch a high altitude balloon during the eclipse: https://eclipseplus.ca/ https://eclipseplus.ca/ We have several cameras on board, including one that points at the sun and one that takes video. It all gets live-streamed to the ground (actually, that's my contribution to the project - the communications system) and sent off to YouTube. We're launching from New Brunswick, Canada, and we'll be going up to about 30km, or 100k feet. So the clouds definitely won't be an issue for us.

nelblu 2y ago
Awesome! I'm driving myself to Kouchibouguac to experience the totality. Considering that maritimes is always cloudy during this time of the year I'm not expecting much of a "view" but just want to experience the total darkness. Where we live (NS) we are getting about 95% darkness but I figured a couple of hours drive is worth to experience 100%!
- scd31 2y ago
  Absolutely. I've never experienced a total eclipse before but I hear the difference between 95% and 100% is stark; due to the logarithmic nature of the human eye. I'm not even sure if 95% coverage would even be noticeable without eclipse glasses. I'm from NS myself (Halifax) and have been trying to convince my parents to drive up to NB to see the eclipse. I'll be home for Easter so that'll probably be my last attempt!
  - ars 2y ago
    Even 99% is barely noticeable. Totality is a different category, it's not just "a bit darker". And a camera is not the same experience as looking around and being in a circle of darkness with a lit horizon in all directions.
    - xattt 2y ago
      Yes, the experience associated with a picture is what matters. Even if it’s a live stream of the eclipse, it’s not too different that looking at photos/videos of other eclipses online. You need to feel the change in air and the sounds to get the whole experience.
  - nelblu 2y ago
    haha took me a couple of attempts to convince my wife too. I'm so looking forward to it though!
- xattt 2y ago
  The adage I’ve heard is that 90+% eclipses only give you 10% experience of totality. I’m in Charlottetown, and I’ll be driving to North Cape (as will the rest of the Island). Between worrying about the weather, I’m also concerned that I won’t be able to get to North Cape in the first place. So far, I managed to beat the solar glasses rush by ordering in January. I’m trying to figure out the timing to get to North Cape early enough to have a spot to park, but not too early that my kids will lose their minds with the waiting.
  - Stratoscope 2y ago
    More accurately, any partial eclipse gives you 0% of the experience of totality. During totality, you see the Sun's corona with your own eyes. In any partial phase, you are seeing the Sun's photosphere - the same bright surface of the Sun you see on every clear day. So you need eye protection. When the Moon completely blocks the photosphere in totality, you get to see the much fainter solar corona. The corona is only about as bright as a full Moon. You don't need and should not use solar glasses during totality. Don't take my word for it, if you get them go out at night and look at the Moon through them (doesn't have to be full). Your kids are fairly young? You want to keep them safe during the partial phases, and also make sure they get to view totality unfiltered. There was a lengthy discussion on Reddit the other day, nominally about photography but also about viewing with your own eyes: https://old.reddit.com/r/photography/comments/1bk7f0l/total_solar_eclipse_ama/ https://old.reddit.com/r/photography/comments/1bk7f0l/total_... It bums me out that there is so much misinformation going around about eclipse viewing safety, specifically the notion that you should wear eclipse glasses during totality. In that same Reddit thread, someone cites a misinformed New York Times article. I'll link it here because it was downvoted and hidden and is worth a quick read (along with our replies) to see how badly mistaken a major news publication can be: https://old.reddit.com/r/photography/comments/1bk7f0l/total_solar_eclipse_ama/kvwm0da/ https://old.reddit.com/r/photography/comments/1bk7f0l/total_...
dylan604 2y ago
How do you keep a camera pointed when attached to a balloon? I've done a similar balloon launch, but very much on the cheap. Our payload had no stabilization, so it just acted as a pendulum under the balloon, and would spin as the torsion of the rope commanded. I've had thoughts after seeing those results, but just never had the opportunity to try it again. Based on the pics on your link, my balloon looked very similar. I'm guessing you'll be using a totally different balloon than those on the landing page.
- scd31 2y ago
  Our payload has no stabilization either, and in past launches we've had quite a bit of rotation and swinging. Here's a video of one of last launch, for reference: https://peertube.scd31.com/w/7CQCYB4BmJzngoZTiMociY https://peertube.scd31.com/w/7CQCYB4BmJzngoZTiMociY To point the camera we have a lot of clever software and hardware. I didn't have any part in it, so I'll try to explain it as best I can. There's a diagram here, which hopefully will help you to follow along: https://eclipseplus.ca/Project_Details/Payload_Design/ https://eclipseplus.ca/Project_Details/Payload_Design/ We have a fixed camera mounted above a mirror. The mirror is on a special gimbal, which can be maneuvered using two servos and a bit of math. For coarse aiming, we have an IMU on board which uses the magnetic field of the Earth to figure out its orientation. For fine aiming, we do a bit of image processing to try and center the sun in the field of view of the camera. It's not perfect, but since we're only capturing still images, it's okay if not all the images have the sun in view. Also of note is the filter, which starts in-place (to protect the optics) and automatically moves out of the way during totality. It also moves back into place afterwards so that we can continue safely taking images after the eclipse. The balloons on the landing page are accurate! Those pictures are from past launches, which used the same payload (with some changes between each launch)
  - dylan604 2y ago
    That's a much more hacker way that my thoughts of adding a swivel to the rope and some sort of tail on the payload to attempt to keep it oriented with the wind. I will definitely keep an eye on your project to see how it works out. It sounds like an interesting idea to be sure. Good luck! Just remember that whatever is happening with the balloon to at least enjoy the event for yourself as well
colechristensen 2y ago
That's quite a lot of bandwidth streaming video up to ~100,000 feet. How are you achieving this?
- scd31 2y ago
  I wrote a bit about it here: https://www.scd31.com/posts/real-time-balloon-video https://www.scd31.com/posts/real-time-balloon-video The actual bandwidth is 500kbps, or about 350kbps usable after FEC. I'm encoding video at 640x480, 12FPS. It's almost entirely custom software. I'm using a Gstreamer pipeline to take in the video stream, encode it, and encapsulate it. From there, I packetize it, run it through an LDPC encoder (for error correction), data whitening, and finally send it to an FSK modem to convert it into radio waves. On the ground station I basically do the same thing in reverse. At 1W transmission, I've gotten video over 140km from a balloon to the ground. Most of that distance is horizontal - the winds tend to blow the balloon quite far. The math says the system should be good to at least 250km.

by scd31 2y ago

nelblu 2y ago

Awesome! I'm driving myself to Kouchibouguac to experience the totality. Considering that maritimes is always cloudy during this time of the year I'm not expecting much of a "view" but just want to experience the total darkness. Where we live (NS) we are getting about 95% darkness but I figured a couple of hours drive is worth to experience 100%!

scd31 2y ago
Absolutely. I've never experienced a total eclipse before but I hear the difference between 95% and 100% is stark; due to the logarithmic nature of the human eye. I'm not even sure if 95% coverage would even be noticeable without eclipse glasses. I'm from NS myself (Halifax) and have been trying to convince my parents to drive up to NB to see the eclipse. I'll be home for Easter so that'll probably be my last attempt!
- ars 2y ago
  Even 99% is barely noticeable. Totality is a different category, it's not just "a bit darker". And a camera is not the same experience as looking around and being in a circle of darkness with a lit horizon in all directions.
  - xattt 2y ago
    Yes, the experience associated with a picture is what matters. Even if it’s a live stream of the eclipse, it’s not too different that looking at photos/videos of other eclipses online. You need to feel the change in air and the sounds to get the whole experience.
- nelblu 2y ago
  haha took me a couple of attempts to convince my wife too. I'm so looking forward to it though!
xattt 2y ago
The adage I’ve heard is that 90+% eclipses only give you 10% experience of totality. I’m in Charlottetown, and I’ll be driving to North Cape (as will the rest of the Island). Between worrying about the weather, I’m also concerned that I won’t be able to get to North Cape in the first place. So far, I managed to beat the solar glasses rush by ordering in January. I’m trying to figure out the timing to get to North Cape early enough to have a spot to park, but not too early that my kids will lose their minds with the waiting.
- Stratoscope 2y ago
  More accurately, any partial eclipse gives you 0% of the experience of totality. During totality, you see the Sun's corona with your own eyes. In any partial phase, you are seeing the Sun's photosphere - the same bright surface of the Sun you see on every clear day. So you need eye protection. When the Moon completely blocks the photosphere in totality, you get to see the much fainter solar corona. The corona is only about as bright as a full Moon. You don't need and should not use solar glasses during totality. Don't take my word for it, if you get them go out at night and look at the Moon through them (doesn't have to be full). Your kids are fairly young? You want to keep them safe during the partial phases, and also make sure they get to view totality unfiltered. There was a lengthy discussion on Reddit the other day, nominally about photography but also about viewing with your own eyes: https://old.reddit.com/r/photography/comments/1bk7f0l/total_solar_eclipse_ama/ https://old.reddit.com/r/photography/comments/1bk7f0l/total_... It bums me out that there is so much misinformation going around about eclipse viewing safety, specifically the notion that you should wear eclipse glasses during totality. In that same Reddit thread, someone cites a misinformed New York Times article. I'll link it here because it was downvoted and hidden and is worth a quick read (along with our replies) to see how badly mistaken a major news publication can be: https://old.reddit.com/r/photography/comments/1bk7f0l/total_solar_eclipse_ama/kvwm0da/ https://old.reddit.com/r/photography/comments/1bk7f0l/total_...

dylan604 2y ago

How do you keep a camera pointed when attached to a balloon? I've done a similar balloon launch, but very much on the cheap. Our payload had no stabilization, so it just acted as a pendulum under the balloon, and would spin as the torsion of the rope commanded. I've had thoughts after seeing those results, but just never had the opportunity to try it again. Based on the pics on your link, my balloon looked very similar. I'm guessing you'll be using a totally different balloon than those on the landing page.

scd31 2y ago
Our payload has no stabilization either, and in past launches we've had quite a bit of rotation and swinging. Here's a video of one of last launch, for reference: https://peertube.scd31.com/w/7CQCYB4BmJzngoZTiMociY https://peertube.scd31.com/w/7CQCYB4BmJzngoZTiMociY To point the camera we have a lot of clever software and hardware. I didn't have any part in it, so I'll try to explain it as best I can. There's a diagram here, which hopefully will help you to follow along: https://eclipseplus.ca/Project_Details/Payload_Design/ https://eclipseplus.ca/Project_Details/Payload_Design/ We have a fixed camera mounted above a mirror. The mirror is on a special gimbal, which can be maneuvered using two servos and a bit of math. For coarse aiming, we have an IMU on board which uses the magnetic field of the Earth to figure out its orientation. For fine aiming, we do a bit of image processing to try and center the sun in the field of view of the camera. It's not perfect, but since we're only capturing still images, it's okay if not all the images have the sun in view. Also of note is the filter, which starts in-place (to protect the optics) and automatically moves out of the way during totality. It also moves back into place afterwards so that we can continue safely taking images after the eclipse. The balloons on the landing page are accurate! Those pictures are from past launches, which used the same payload (with some changes between each launch)
- dylan604 2y ago
  That's a much more hacker way that my thoughts of adding a swivel to the rope and some sort of tail on the payload to attempt to keep it oriented with the wind. I will definitely keep an eye on your project to see how it works out. It sounds like an interesting idea to be sure. Good luck! Just remember that whatever is happening with the balloon to at least enjoy the event for yourself as well

colechristensen 2y ago

That's quite a lot of bandwidth streaming video up to ~100,000 feet. How are you achieving this?

scd31 2y ago
I wrote a bit about it here: https://www.scd31.com/posts/real-time-balloon-video https://www.scd31.com/posts/real-time-balloon-video The actual bandwidth is 500kbps, or about 350kbps usable after FEC. I'm encoding video at 640x480, 12FPS. It's almost entirely custom software. I'm using a Gstreamer pipeline to take in the video stream, encode it, and encapsulate it. From there, I packetize it, run it through an LDPC encoder (for error correction), data whitening, and finally send it to an FSK modem to convert it into radio waves. On the ground station I basically do the same thing in reverse. At 1W transmission, I've gotten video over 140km from a balloon to the ground. Most of that distance is horizontal - the winds tend to blow the balloon quite far. The math says the system should be good to at least 250km.