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(Disclaimer: I know ~nothing about astronomy) The other claim I've seen is that once the satellites reach their operational orbit (~4 months after launch), the

by mh- 5y ago

(Disclaimer: I know ~nothing about astronomy) The other claim I've seen is that once the satellites reach their operational orbit (~4 months after launch), they are no longer visible. I don't know if this has been proven/disproven yet. Curious if anyone in-the-know can comment.

ortusdux 5y ago
They are no longer visible to the naked eye. The satellites are initially inserted at ~half their final orbit. They then boot up, deploy their solar panels horizontally to reduce drag, and then fire up their engines for the boost to their final orbit. This takes about a month or so. Once there, they rotate their panels to point away from the earth, which greatly reduces their apparent brightness.
mlindner 5y ago
You're correct that they are no longer visible to the naked eye. They're reduced down to (right now) approximately 6th magnitude and SpaceX is trying to get them down to 7th magnitude. The human eye in a perfectly or almost perfectly dark sky can see down to roughly (humans vary quite a bit) 6th magnitude but it would be very hard, especially for a moving object. In order to see 6th magnitude you need a very dark sky (no moon or clouds, low humidity, no human populations anywhere nearby), you would need to dark adapt for over 30 minutes with no viewing of any sources of light, you'd need to be pretty young, and then you'd need to use averted-vision viewing where you look near an object, but not directly at it such that you can use the higher density of rods in the rest of your eye in order to see the object. You'd then have a chance of seeing current Starlink satellites, but you'd see a ton of other satellites as well as there's many satellites above 6th magnitude. (In 2017 or so I was in rural Nebraska the night before the solar eclipse and it felt like there was a half dozen visible satellites in the sky at any given time.) However that doesn't mean they're not visible to telescopes.

by mh- 5y ago

ortusdux 5y ago

They are no longer visible to the naked eye. The satellites are initially inserted at ~half their final orbit. They then boot up, deploy their solar panels horizontally to reduce drag, and then fire up their engines for the boost to their final orbit. This takes about a month or so. Once there, they rotate their panels to point away from the earth, which greatly reduces their apparent brightness.

mlindner 5y ago

You're correct that they are no longer visible to the naked eye. They're reduced down to (right now) approximately 6th magnitude and SpaceX is trying to get them down to 7th magnitude. The human eye in a perfectly or almost perfectly dark sky can see down to roughly (humans vary quite a bit) 6th magnitude but it would be very hard, especially for a moving object. In order to see 6th magnitude you need a very dark sky (no moon or clouds, low humidity, no human populations anywhere nearby), you would need to dark adapt for over 30 minutes with no viewing of any sources of light, you'd need to be pretty young, and then you'd need to use averted-vision viewing where you look near an object, but not directly at it such that you can use the higher density of rods in the rest of your eye in order to see the object. You'd then have a chance of seeing current Starlink satellites, but you'd see a ton of other satellites as well as there's many satellites above 6th magnitude. (In 2017 or so I was in rural Nebraska the night before the solar eclipse and it felt like there was a half dozen visible satellites in the sky at any given time.) However that doesn't mean they're not visible to telescopes.