APOD: Stars Trail over Ragusa (2020 Mar 28)

[Chris Peterson]

Hi Chris, many thanks for your annotation. But there now is a request.

You are sure, that starlink is nearly invisible? Maybe, there will be ca. 7000 in LEO at a hight of appr. 340 km. But there will also be 1500 at an orbit of 550 km and 2500 at 1200 km. And ... why is the ISS on an LEO-orbit of 350 to 400km visible always, worldwide and even at midnight? Fake pictures and observations? And the photo of Debra Ceravolo ... is it manipulation ... photoshop? And your last annotation "interesting, too" ... should I change my observatory to a location near to an airport to get more interesting astrophotos?

I recommend to take the problem with starlink seriously!

Gotthard

ISS is rarely visible except near sunrise or sunset (particularly high in the sky where most astronomical observation takes place).

There is little to suggest that a large satellite constellation will have much impact on astronomy. The only major issue right now is with a couple of wide field survey telescopes, but it looks like darkening the satellites will solve most of the problems there. For a great many people, these will be like Iridium flares- something cool to see.

I view the entire thing as a huge social benefit (I'll be first in line to sign up for service) offset by very little harm.

[geckzilla]

Hi Chris, many thanks for your annotation. But there now is a request.

You are sure, that starlink is nearly invisible? Maybe, there will be ca. 7000 in LEO at a hight of appr. 340 km. But there will also be 1500 at an orbit of 550 km and 2500 at 1200 km. And ... why is the ISS on an LEO-orbit of 350 to 400km visible always, worldwide and even at midnight? Fake pictures and observations? And the photo of Debra Ceravolo ... is it manipulation ... photoshop? And your last annotation "interesting, too" ... should I change my observatory to a location near to an airport to get more interesting astrophotos?

I recommend to take the problem with starlink seriously!

Gotthard

ISS is rarely visible except near sunrise or sunset (particularly high in the sky where most astronomical observation takes place).

There is little to suggest that a large satellite constellation will have much impact on astronomy. The only major issue right now is with a couple of wide field survey telescopes, but it looks like darkening the satellites will solve most of the problems there. For a great many people, these will be like Iridium flares- something cool to see.

I view the entire thing as a huge social benefit (I'll be first in line to sign up for service) offset by very little harm.

Er, this is quite contrary to all that I've read about them. Darkening them hasn't helped (there's one test dark sat, and it looks the same as the rest) and the huge social benefit just ain't there. The constellation can't support that many users or that much bandwidth. The entire thing is a bit of a sham, if you ask me.

[Chris Peterson]

Hi Chris, many thanks for your annotation. But there now is a request.

You are sure, that starlink is nearly invisible? Maybe, there will be ca. 7000 in LEO at a hight of appr. 340 km. But there will also be 1500 at an orbit of 550 km and 2500 at 1200 km. And ... why is the ISS on an LEO-orbit of 350 to 400km visible always, worldwide and even at midnight? Fake pictures and observations? And the photo of Debra Ceravolo ... is it manipulation ... photoshop? And your last annotation "interesting, too" ... should I change my observatory to a location near to an airport to get more interesting astrophotos?

I recommend to take the problem with starlink seriously!

Gotthard

ISS is rarely visible except near sunrise or sunset (particularly high in the sky where most astronomical observation takes place).

There is little to suggest that a large satellite constellation will have much impact on astronomy. The only major issue right now is with a couple of wide field survey telescopes, but it looks like darkening the satellites will solve most of the problems there. For a great many people, these will be like Iridium flares- something cool to see.

I view the entire thing as a huge social benefit (I'll be first in line to sign up for service) offset by very little harm.

Er, this is quite contrary to all that I've read about them. Darkening them hasn't helped (there's one test dark sat, and it looks the same as the rest) and the huge social benefit just ain't there. The constellation can't support that many users or that much bandwidth. The entire thing is a bit of a sham, if you ask me.

The measurements of the darkened satellite suggest that this approach will, in fact, drop the satellites below the blooming threshold of the Rubin Observatory. Without it they would lose about a third of their survey exposures. But they're working closely with Musk and the Starlink people, and the PI seems pretty optimistic that they'll be able to deal with it. Most other astronomy isn't much impacted.

[neufer]

The measurements of the darkened satellite suggest that this approach will, in fact, drop the satellites below the blooming threshold of the Rubin Observatory. Without it they would lose about a third of their survey exposures. But they're working closely with Musk and the Starlink people, and the PI seems pretty optimistic that they'll be able to deal with it. Most other astronomy isn't much impacted.

• Which brings us to the critical question:

Do you personally have a wide-band connection now up in Guffey, Chris

[Chris Peterson]

The measurements of the darkened satellite suggest that this approach will, in fact, drop the satellites below the blooming threshold of the Rubin Observatory. Without it they would lose about a third of their survey exposures. But they're working closely with Musk and the Starlink people, and the PI seems pretty optimistic that they'll be able to deal with it. Most other astronomy isn't much impacted.

• Which brings us to the critical question:

Do you personally have a wide-band connection now up in Guffey, Chris :?:

Nope. On a good day I might get 5 mbps. Usually can't even watch a YouTube video at low resolution. I'll be first in line to sign up for Starlink service. I'll use the satellites themselves as an interest generator at our public star nights, just as I have with Iridiums. And I anticipate no impact at all on my own imaging or meteoritics projects.

[bystander]

viewtopic.php?t=39469#p300138

[geckzilla]

I'm starting to think that you might have some kind of motivated reasoning about it, Chris.

[alter-ego]

ISS is rarely visible except near sunrise or sunset (particularly high in the sky where most astronomical observation takes place).

There is little to suggest that a large satellite constellation will have much impact on astronomy. The only major issue right now is with a couple of wide field survey telescopes, but it looks like darkening the satellites will solve most of the problems there. For a great many people, these will be like Iridium flares- something cool to see.

I view the entire thing as a huge social benefit (I'll be first in line to sign up for service) offset by very little harm.

Er, this is quite contrary to all that I've read about them. Darkening them hasn't helped (there's one test dark sat, and it looks the same as the rest) and the huge social benefit just ain't there. The constellation can't support that many users or that much bandwidth. The entire thing is a bit of a sham, if you ask me.

The measurements of the darkened satellite suggest that this approach will, in fact, drop the satellites below the blooming threshold of the Rubin Observatory. Without it they would lose about a third of their survey exposures. But they're working closely with Musk and the Starlink people, and the PI seems pretty optimistic that they'll be able to deal with it. Most other astronomy isn't much impacted.

I'm optimistic too, but not as much as Musk. He has expressed commitment to reducing the impact on astronomy and has stated that they would reduce the impact to "zero". The great news is he wants to fix it, and he's certainly capable.
However, as far as the first attempt with Darksat, there is a way to go, but there are other ideas.

However, the company’s claim that DarkSat has achieved a “notable reduction” in brightness is not necessarily supported by recent observations. In a paper posted to the online preprint server arXiv March 17, astronomers using a small telescope in Chile measured the brightness of DarkSat and compared it to another Starlink satellite without darkening treatments. They found DarkSat was about 0.88 magnitudes, or 55%, dimmer than the ordinary Starlink satellite.

That falls far short of what many astronomers are seeking. In a March 11 panel discussion organized by the American Astronomical Society, Tony Tyson, chief scientist for the Vera Rubin Observatory under construction in Chile, said that simulations of the Starlink satellites showed that not only would the satellites make bright streaks on images taken by the telescope, but create other image artifacts by saturating pixels in the detector.

“If we could make those particular spacecraft, the Starlinks, darker by 10 to 20 times, it may remove many of these artifacts,” he said. “It won’t remove the main trail — it will always be there — but it would remove the artifacts so that we might be able to get the science out of the data.”

[Chris Peterson]

I'm starting to think that you might have some kind of motivated reasoning about it, Chris.

Of course. I look at things in terms of costs and benefits. The cost to astronomical science in this case seems trivially small in comparison with the massive human benefit of universal data connectivity.

In fact, I predict the astronomical cost will be essentially zero. This has no impact on amateur imagers, and virtually none on any professional optical astronomy except for a couple of survey telescopes, and it appears a solution to that problem is well under way. The only uncertainty here is if there will be some interference with radio astronomy... which seems to not be settled yet.

[Chris Peterson]

Er, this is quite contrary to all that I've read about them. Darkening them hasn't helped (there's one test dark sat, and it looks the same as the rest) and the huge social benefit just ain't there. The constellation can't support that many users or that much bandwidth. The entire thing is a bit of a sham, if you ask me.

The measurements of the darkened satellite suggest that this approach will, in fact, drop the satellites below the blooming threshold of the Rubin Observatory. Without it they would lose about a third of their survey exposures. But they're working closely with Musk and the Starlink people, and the PI seems pretty optimistic that they'll be able to deal with it. Most other astronomy isn't much impacted.

I'm optimistic too, but not as much as Musk. He has expressed commitment to reducing the impact on astronomy and has stated that they would reduce the impact to "zero". The great news is he wants to fix it, and he's certainly capable.
However, as far as the first attempt with Darksat, there is a way to go, but there are other ideas.

However, the company’s claim that DarkSat has achieved a “notable reduction” in brightness is not necessarily supported by recent observations. In a paper posted to the online preprint server arXiv March 17, astronomers using a small telescope in Chile measured the brightness of DarkSat and compared it to another Starlink satellite without darkening treatments. They found DarkSat was about 0.88 magnitudes, or 55%, dimmer than the ordinary Starlink satellite.

That falls far short of what many astronomers are seeking. In a March 11 panel discussion organized by the American Astronomical Society, Tony Tyson, chief scientist for the Vera Rubin Observatory under construction in Chile, said that simulations of the Starlink satellites showed that not only would the satellites make bright streaks on images taken by the telescope, but create other image artifacts by saturating pixels in the detector.

“If we could make those particular spacecraft, the Starlinks, darker by 10 to 20 times, it may remove many of these artifacts,” he said. “It won’t remove the main trail — it will always be there — but it would remove the artifacts so that we might be able to get the science out of the data.”

To be clear, most projects either have a low probability of a satellite passing through, or can be timed to avoid them. The major issue is with wide field surveys, and for those, satellite tracks are not a problem unless they are bright enough to cause blooming. That's the goal of the darkening efforts. Not to make tracks go away, but avoid deep saturation, which ruins large sections of the image.

[geckzilla]

I'm starting to think that you might have some kind of motivated reasoning about it, Chris.

<snip> the massive human benefit of universal data connectivity. <snip>

It's not going to be universal. The system throughput is going to be too low for many people to use at one time, so cross out the world's huge, impoverished population. Do they get to take turns? People who live under totalitarian regimes won't even be able to access it, because SpaceX won't risk having their sats shot down by undermining their authority. Who do I think ends up using it? Rich, secluded folks like you. Maybe.

[Chris Peterson]

I'm starting to think that you might have some kind of motivated reasoning about it, Chris.

<snip> the massive human benefit of universal data connectivity. <snip>

It's not going to be universal. The system throughput is going to be too low for many people to use at one time, so cross out the world's huge, impoverished population. Do they get to take turns? People who live under totalitarian regimes won't even be able to access it, because SpaceX won't risk having their sats shot down by undermining their authority. Who do I think ends up using it? Rich, secluded folks like you. Maybe.

Well, there is that pessimistic view. But I don't think that's a likely scenario. The system in its final state will support enough bandwidth for hundreds of millions to have reasonable, inexpensive access. And the few countries that might negotiate their territory out of coverage are already capable of offering access... so the problem is the country, not the technology.

I think the future of Internet access, for much of the world, across all economic classes, is space-base. It just makes sense. And comes with little harm.

[neufer]

<snip> the massive human benefit of universal data connectivity. <snip>

It's not going to be universal. The system throughput is going to be too low for many people to use at one time, so cross out the world's huge, impoverished population. Do they get to take turns? People who live under totalitarian regimes won't even be able to access it, because SpaceX won't risk having their sats shot down by undermining their authority. Who do I think ends up using it? Rich, secluded folks like you. Maybe.

Well, there is that pessimistic view. But I don't think that's a likely scenario. The system in its final state will support enough bandwidth for hundreds of millions to have reasonable, inexpensive access. And the few countries that might negotiate their territory out of coverage are already capable of offering access... so the problem is the country, not the technology.

I think the future of Internet access, for much of the world, across all economic classes, is space-base. It just makes sense. And comes with little harm.

Hmmm... dark sky envy vs. internet envy(...color the Universe green).

Poor secluded folks would probably much rather have internet connectivity than dark skies.

(Feel free to "release the hounds" on Geck if you like, Chris.)

[Chris Peterson]

It's not going to be universal. The system throughput is going to be too low for many people to use at one time, so cross out the world's huge, impoverished population. Do they get to take turns? People who live under totalitarian regimes won't even be able to access it, because SpaceX won't risk having their sats shot down by undermining their authority. Who do I think ends up using it? Rich, secluded folks like you. Maybe.

Well, there is that pessimistic view. But I don't think that's a likely scenario. The system in its final state will support enough bandwidth for hundreds of millions to have reasonable, inexpensive access. And the few countries that might negotiate their territory out of coverage are already capable of offering access... so the problem is the country, not the technology.

I think the future of Internet access, for much of the world, across all economic classes, is space-base. It just makes sense. And comes with little harm.

Hmmm... dark sky envy vs. internet envy(...color the Universe green).

Poor secluded folks would probably much rather have internet connectivity than dark skies.

(Feel free to "release the hounds" on Geck if you like, Chris.)

Dark skies are very important to me. That would be a tough call, dark skies versus Internet. But these satellite constellations have no impact on sky darkness, nor on astronomical observing, and are largely insignificant for astronomical imaging. So I see no real downside, and lots of benefit.

[geckzilla]

Yeah, I'm sure it will work out and everyone will get it and all our problems will be solved, just like the solar tiles and the transit tunnels (were trains going in those or cars? I forgot).

[Chris Peterson]

Yeah, I'm sure it will work out and everyone will get it and all our problems will be solved, just like the solar tiles and the transit tunnels (were trains going in those or cars? I forgot).

Well, the solar tiles are pretty good, and getting better. But there's a wide range between "everything working out" and "a useful, socially beneficial tool".