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Planet: Imaging the entire Earth every day

nbremer.github.io

41–50 of 144 posts

Re: Planet: Imaging the entire Earth every day

#41
post #25

"This visualization doesn't work right on Firefox+Linux, sorry! You could try Chrome/Chromium instead." No Thanks.

Seems to work fine here (Firefox 68.0, Radeon R370, Fedora 5.2.7-100.fc29.x86_64, KDE/X-Window). That is, I can see the satellites and the rotating globe with strips of land gradually revealed.

Re: Planet: Imaging the entire Earth every day

#43

Stupid question: how do they measure speed of the satellite? I mean, on the website they've mentioned the speed of one of their satellite as ~7.6 kmps. Is that the actual speed of the satellite or it's a measure of how much land the the satellite covers per second?

Not an expert. But there are a few ways to look at this. Bodies that are in stable orbit can have only a specific velocity which is a function of its distance from & mass of whatever it is orbiting. So orbiting satellite's speed can be inferred from its orbital height. There are ground based tracking stations that can technically measure the speed of any orbiting body. Also read somewhere that LEO satellites could us…

Ah! Got it. Thanks!

Re: Planet: Imaging the entire Earth every day

#44
post #32

Earlier quoted context omitted.

If you could track the satellite could you not shine a laser, or bright light (maybe a mirror reflecting the sun) directly at the camera to mess up the imaging while over your region?

And if an aircraft flies over your property you could get charged with a federal offense (pointing a laser at an aircraft).

Ehhhh, the aircraft flew into the trajectory, are there no other comparable scenarios where there's an intersection that can happen accidentally?

Re: Planet: Imaging the entire Earth every day

#45
post #39

Stupid question: how do they measure speed of the satellite? I mean, on the website they've mentioned the speed of one of their satellite as ~7.6 kmps. Is that the actual speed of the satellite or it's a measure of how much land the the satellite covers per second?

The orbital velocity and the ground track velocity only differ by about 6.6% for their 450km orbit, so it's not a big difference. But because they have a relatively circular orbit, you can use the formula sqrt(G*M/R) which gives 7.639km/sec -- so it looks like they are referring to true orbital velocity.

This is helpful, thanks!

Re: Planet: Imaging the entire Earth every day

#46

Stupid question: how do they measure speed of the satellite? I mean, on the website they've mentioned the speed of one of their satellite as ~7.6 kmps. Is that the actual speed of the satellite or it's a measure of how much land the the satellite covers per second?

They can measure it by altitude. An orbiting object always has a defined velocity at any point of its orbit. For example, a circular orbit 500km above Earth's surface amounts to velocity of 7.61 km/s everywhere on it.

Makes sense. This is helpful. Thanks, TeMPOral!

Re: Planet: Imaging the entire Earth every day

#47
post #33
post #25

"This visualization doesn't work right on Firefox+Linux, sorry! You could try Chrome/Chromium instead." No Thanks.

Chromium doesn't have all that tracking stuff right. What's wrong with it?

When Microsoft took the Chromium browser as a base for the new Edge version, they replaced over 50 Google services.

[1] https://www.theverge.com/2019/4/8/18300772/microsoft-google-...

Re: Planet: Imaging the entire Earth every day

#48
post #33
post #25

"This visualization doesn't work right on Firefox+Linux, sorry! You could try Chrome/Chromium instead." No Thanks.

Chromium doesn't have all that tracking stuff right. What's wrong with it?

It drives the people towards having one browser controlled by a mega corporation. We, at the very least, as developers need to support multiple browsers to prevent the monopolization that could one-day threaten the current style and freedom of the internet that we admire and like (generally).

Re: Planet: Imaging the entire Earth every day

#49
post #25

"This visualization doesn't work right on Firefox+Linux, sorry! You could try Chrome/Chromium instead." No Thanks.

The visualisation works fine in newest Firefox on Linux, though only in Chromium do I get the sound effects (like a high pitched fan noise)
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