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Based on earlier discussions, I thought it was really hard to see a satellite if you don't know the orbit. I did some calculations, and a 15m object (largest t
by rocqua 9y ago
Based on earlier discussions, I thought it was really hard to see a satellite if you don't know the orbit.
I did some calculations, and a 15m object (largest that fits in falcon 9) at 300km (lowest orbit) has an angular diameter of 0.006 degrees.
That amounts to taking up about 0.000005% of the sky above the horizon.
I figured the required resolution to cover the sky well enough to see that would be ridiculous, but 20 megapixels spread over the entire sky would then be enough that this satellite could occlude an entire pixel.
Considering how many hobbyists there are, this does indeed seem feasible.
- vlasev 9y agoThe angular diameter of stars that are light-years away are really really small. Yet they are visible to the naked eye and cameras all the time. So it's not just about the angular diameter.
- jacquesm 9y agoBut they shine a lot of light in every direction, including directly at you, the observer. So even if they are small they compensate for that by their power output and the fact that their radiation is a near perfect sphere. A satellite trying hard to hide isn't going to be nearly as friendly as that for an observer.
- planteen 9y agoHow are you going to power said satellite? Those massive solar arrays are going to reflect emag across the spectrum (radar returns and solar returns).
- nradov 9y agoYou don't have to scan the entire sky. Based on knowing the the approximate launch trajectory, there are only a limited range of orbits where the satellite could possibly be. Satellites have very limited fuel and can only make small orbital changes.