Satellites are only visible shortly after sunset and before sunrise, known as astronomical twilight.
If the images in the photograph upset you and you think our night sky is ruined, the thing that kills it the most is light pollution. Flood lights, parking lights, and street lights that don’t direct light down to the ground make viewing much worse than satellites for everybody.
It’s just as easy to capture incredible images of the night sky, even during astronomical twilight, with image processing. Here’s photos I’ve captured in my driveway in the SF Bay Area: https://bradgessler.github.io/observatory-blog/observations/
I captured said images with an Elixir software stack I installed on a Pi and hooked up to my telescope. It’s open-source at https://github.com/bradgessler/observatory for those who are interested. I hook Claude up to it and it runs observations for the night, processes images with deterministic tools, and publishes them as the night progresses.
People on HN who are "upset", or believe (correctly, of course) that night sky observation/recording/appreciation is increasingly impeded over time, do not feel that way because of this image.
Yes, terrestrial light pollution has been the number one problem since we invented electric lights, but satellites and terrestrial light pollution are both separate problems with different effects and different coverage. E.g. even though light pollution is much more harmful, you can escape it with a short drive, even if you live in a densely populated region. You can't escape the strings of satellites.
Separately: "Shortly after sunset" is a downplay. It can be hours. But in any case, it's the time when the vast majority of stargazers are looking at the stars (with their eyes).
Satellites have the same awkward sociopolitical energy infecting them as all tech does nowadays. But remember: There is absolutely nothing wrong with being upset about the effect of these satellites, just like there is absolutely nothing wrong with being upset about the effect of electric lights. You can certainly get a lot of mileage out of weighing this against the consequences of having much fewer satellites, and that's exactly where all the argument should be occupied. That they affect the night sky, which reasonably annoys many people, is just a fact.
In the summer they can be visible for up to four hours after sunset. Since summer nights are the most pleasant for being outside, and the sun sets quite late, it is a serious issue for the casual stargazer. When I go camping I look up at the night sky after dinner and just see satellite after satellite after satellite.
For naked eye observations definitely not a problem in comparison with light polution. Though for astronomers, especially those looking with sensitive instruments (SIPM and SPAD cameras) for transient events (like asteroid occultation or ultrafast photometery) all those satellites will create fake signals - about 1ms dips in the brightness now and then.
Even if humanity becomes an inter-stellar civilization, we will still have satellites polluting the night-sky on any planet! They are an eternal fixture of our civilization now - as long as we don't go extinct.
This is awesome. How far we have come in the last century. How much farther we have to go. We will conquer the skies, and then the stars.
I remember thinking when I was a child how exciting the future was going to be. I had a bunch of these books talking about space and ships and stuff. Well, the future lived up to billing. We got there.
A lot of people are going to look at that manually edited image, think it's a traditional long-exposure photo, and conclude that satellites are much more of a problem for astronomy than they really are.
The photographer made a really neat picture, but Kottke is presenting it with a headline that suggests its something else, and generally not giving enough context (mostly just blockquotes).
Ironically, the same technique used to remove the stars and isolate the satellites could have been used to remove the satellites and isolate the stars.
It would take 100X less effort to remove the satellites.
> Much of the time was spent painstakingly erasing stars, to reveal the satellites.
Many more stars than satellites in every frame. Erasing a couple satellites at most is quick. Erasing every star in the sky and keeping a couple satellites is not.
Yes, this image is hand-crafted art that looks cool, but in fact both approaches can and have have been automated!
- Astronomers have automated software that anticipates each streak based on the space object catalog and automatically removes satellites from long-exposure wide field-of-view images.
- Those whose job is to track satellites and update the space object catalog have software that anticipates each star location based on star catalogs, and automatically removes stars so they can see where the satellites are.
Its parameters are very well described and the result is beautiful (visually), interesting, and provocative. Yes, people will misinterpret all sorts of things like this, but I don't know what else the author could have done besides not create it at all, for fear of... these accusations?
The hard part came next. Larsen spent about 45 hours layering the individual photos – each of which contained about 25 satellites – over one another, using Adobe Photoshop. Much of the time was spent painstakingly erasing stars, to reveal the satellites.
This is less an "image of our satellite-choked night skies" and more "a completely mendacious image produced using Photoshop".
You are being uncharitable. There is nothing misleading about this, or any other, nightsky timeseries image. It claims to show the paths of satellites over 2 hours, and that's what it does. You have to edit things like this to reveal the signal and keep relatively constant elements from overwhelming the result. Astronomers do this exact same thing (erasing things that obscure the subject over time).
Even if I were to be as charitable as possible to your interpretation, "mendacious" is way too strong a word, and implies an unreasonable bitterness.
I have no problem with the image and it illustrates a real phenomena. There is something slightly misleading about it though: if you point a camera in the same direction for 2 hours, take many images and then layer the images you wouldn't have a static star background like is shown here. You'd only get that star background if you used a star tracker and kept pointing at the same place in the night sky but then the foreground would be changing.
The purpose of stacking hundreds of photos is to get rid of noise and unwanted trails like this.
The effort involved here is to go out of your way to do the exact opposite, specifically make sure things that are in a single exposure show up in the stack.
The guy who actually made the image seems to just think it's cool: "I knew if I carried on it would look even better and more impressive in terms of satellite numbers."
But the framing from others is terrible. "Who gave anyone permission do this?" Um, every single satellite ever launched has gone through government approvals. Sorry if you didn't start paying attention to the world of space flight until it ruined your attempt at photography, but that's on you.
lol what. Regular citizens don’t get a say on satellites and many would prefer we didn’t put so many up. “National Security” will trump any citizen concerns every time.
If you do the exact opposite then? You take a very long exposure and you mask away the satellite trails and post the image as "image of how the satellites don't pollute the sky".. that's the exact same thing in reverse.
> You have to edit things like this to reveal the signal
In this case, it seems like a desired noise was selectively amplified above signal level to portray an artificially low signal-to-noise ratio, with the article concluding "look at all this noise!"
I don't understand. Are you laboring under the impression that the artist is trying to convince people that this is what the night sky looks like at any given moment? What even are you upset about?
The misleading part is that readers don’t see that it’s provocative art until you carefully read the details. It’s presented like documentary evidence of what the problem looks like.
The photographer might not have intended it this way, but the writers of this post took advantage of that.
There's nothing misleading about removing light sources to reveal other light sources. You're speaking as though they erased all the sky's stars. The image is full of stars. This is petty.
I’m quoting the article where the photographer erased the stars from the frames:
> Much of the time was spent painstakingly erasing stars, to reveal the satellites.
These aren’t my words. It’s what the article says!
The final image appears to have a frame of stars added for effect, but they are dots rather than arcs because they’re from a single exposure. The satellite trails are a composite of all of the images, with the stars removed.
Almost any astronomy processing software does this for free, because when you stack a whole load of images it rejects outlier pixels (e.g. a trail present on only one image out of hundreds).
It then usually gives you an image of both the combined success, and an image of just those pixels that were rejected. So, this.
I was thinking the field of astronomy would need to survey the satellites, in order to make sure it doesn't interere with any of their observations of the stars.
So, they would erase the stars, but only to create a satellite mask, generally speaking.
Actually, this is pretty common for non-scientific astrophotography! Erase Stars -> Edit background and stars colour, contrast etc separately -> Recombine!
The photographer was completely transparent about how the image was produced and what it means.. how you manage to color this as dishonest is beyond me.
Technically it is a limited resource, since there is only a finite volume. But we're nowhere near close to any notion of it being "full." Efficient rent would be approximately zero.
To whom would they pay 'rent'? What would be done with the money?
Don't go there, it leads to nothing but more waste, abuse and corruption. If it becomes necessary there can be some form of arbitrage in how LEO is used, we're not there yet though. Maybe something like the auctions for bandwidth for mobile operators but again, where does the money go? If institutionalised it will just turn into another slush fund for whatever interests, many of them corrupt or nonsensical, to drain.
Most satellites in low orbit are Starlink, and most Starlink satellites are at either 43° or 53° inclinations, so it's probably those. These inclinations cover most of the population in the most efficient manner. Low inclinations don't cover people at higher latitudes. (Inclination is equal to the highest latitude that the satellite will reach, and then coverage extends a little further since they have some slant range.) Higher inclinations waste more time over unpopulated regions.
I guess given we have the location, time and what looks like venus to the bottom right it should be possible to figure out the direction the picture was taken in to figure out the exact inclinations of the orbits but yeah, makes sense it'd be starlink
It is a bit ridiculous these days and it's only going to get worse with basically every major country needing to do a version of this for defence purposes.
Go out tonight and just look at the sky for 5 mins and I'll guarantee you'll see a couple of satellites flying past.
As with a lot of other technologies, the genie is out of the bottle and I don't think we're putting him back there again, this is the future.
What makes it "ridiculous"? I can go outside and look at the sky for five minutes and see airplanes flying past, does that mean our air traffic is also ridiculous?
Of all the things to be outraged over... satellites provide extremely valuable services and are pretty near harmless. There's the pollution from the launches, some uncertain concern over putting materials into the upper atmosphere when they reenter, and that's about it. The thing people complain about most is that they get in the way of photographs of the starts. Which is annoying, but also seems to be easily worked around, and is pretty small potatoes compared to planet-wide communications. Your neighbor operating a leaf blower with a dirty two-stroke engine is harming you more than these satellites are.
Satellites are only visible shortly after sunset and before sunrise, known as astronomical twilight.
If the images in the photograph upset you and you think our night sky is ruined, the thing that kills it the most is light pollution. Flood lights, parking lights, and street lights that don’t direct light down to the ground make viewing much worse than satellites for everybody.
It’s just as easy to capture incredible images of the night sky, even during astronomical twilight, with image processing. Here’s photos I’ve captured in my driveway in the SF Bay Area: https://bradgessler.github.io/observatory-blog/observations/
I captured said images with an Elixir software stack I installed on a Pi and hooked up to my telescope. It’s open-source at https://github.com/bradgessler/observatory for those who are interested. I hook Claude up to it and it runs observations for the night, processes images with deterministic tools, and publishes them as the night progresses.
Yes, terrestrial light pollution has been the number one problem since we invented electric lights, but satellites and terrestrial light pollution are both separate problems with different effects and different coverage. E.g. even though light pollution is much more harmful, you can escape it with a short drive, even if you live in a densely populated region. You can't escape the strings of satellites.
Separately: "Shortly after sunset" is a downplay. It can be hours. But in any case, it's the time when the vast majority of stargazers are looking at the stars (with their eyes).
Satellites have the same awkward sociopolitical energy infecting them as all tech does nowadays. But remember: There is absolutely nothing wrong with being upset about the effect of these satellites, just like there is absolutely nothing wrong with being upset about the effect of electric lights. You can certainly get a lot of mileage out of weighing this against the consequences of having much fewer satellites, and that's exactly where all the argument should be occupied. That they affect the night sky, which reasonably annoys many people, is just a fact.
I remember thinking when I was a child how exciting the future was going to be. I had a bunch of these books talking about space and ships and stuff. Well, the future lived up to billing. We got there.
The photographer made a really neat picture, but Kottke is presenting it with a headline that suggests its something else, and generally not giving enough context (mostly just blockquotes).
It would take 100X less effort to remove the satellites.
You're just pointing out that there are tools to automate this.
It’s ironic because stars outnumber visible satellites by a lot, so exiting out the stars is a lot more work than the satellites.
> Much of the time was spent painstakingly erasing stars, to reveal the satellites.
Many more stars than satellites in every frame. Erasing a couple satellites at most is quick. Erasing every star in the sky and keeping a couple satellites is not.
- Astronomers have automated software that anticipates each streak based on the space object catalog and automatically removes satellites from long-exposure wide field-of-view images.
- Those whose job is to track satellites and update the space object catalog have software that anticipates each star location based on star catalogs, and automatically removes stars so they can see where the satellites are.
Headline writer, a different person, used it to create misleading headlines.
There I fixed it for you. This isn't a photo in any traditional sense.
This is less an "image of our satellite-choked night skies" and more "a completely mendacious image produced using Photoshop".
Even if I were to be as charitable as possible to your interpretation, "mendacious" is way too strong a word, and implies an unreasonable bitterness.
The purpose of stacking hundreds of photos is to get rid of noise and unwanted trails like this.
The effort involved here is to go out of your way to do the exact opposite, specifically make sure things that are in a single exposure show up in the stack.
You stack photos to enhance clarity and remove noise. Your work is not "mendacious".
But what you are removing is still data - and as you can see, some people find it to be very interesting.
The headline is the worst offender, saying that the skies are “choked” with satellites.
The headline is misleading. The photo alone is interesting with the right context.
But the framing from others is terrible. "Who gave anyone permission do this?" Um, every single satellite ever launched has gone through government approvals. Sorry if you didn't start paying attention to the world of space flight until it ruined your attempt at photography, but that's on you.
Both can't be non-misleading right?
In this case, it seems like a desired noise was selectively amplified above signal level to portray an artificially low signal-to-noise ratio, with the article concluding "look at all this noise!"
The image in the original post is not too far from what you get with an actual telescope.
The misleading part is that readers don’t see that it’s provocative art until you carefully read the details. It’s presented like documentary evidence of what the problem looks like.
The photographer might not have intended it this way, but the writers of this post took advantage of that.
The misleading part is where he edited out the stars by hand.
> Much of the time was spent painstakingly erasing stars, to reveal the satellites.
The photographer wasn’t misleading. He made a cool photo. The headline is misleading.
> Much of the time was spent painstakingly erasing stars, to reveal the satellites.
These aren’t my words. It’s what the article says!
The final image appears to have a frame of stars added for effect, but they are dots rather than arcs because they’re from a single exposure. The satellite trails are a composite of all of the images, with the stars removed.
Surely an astronomer would have software for this that would produce a more accurate picture.
It then usually gives you an image of both the combined success, and an image of just those pixels that were rejected. So, this.
So, they would erase the stars, but only to create a satellite mask, generally speaking.
with now https://satellitemap.space/s/R4YUwDQn
If so, do Starlink and others pay rent? Should they (to ensure efficient use of the resource)?
https://outerspaceinstitute.ca/crashclock/
Don't go there, it leads to nothing but more waste, abuse and corruption. If it becomes necessary there can be some form of arbitrage in how LEO is used, we're not there yet though. Maybe something like the auctions for bandwidth for mobile operators but again, where does the money go? If institutionalised it will just turn into another slush fund for whatever interests, many of them corrupt or nonsensical, to drain.
Go out tonight and just look at the sky for 5 mins and I'll guarantee you'll see a couple of satellites flying past.
As with a lot of other technologies, the genie is out of the bottle and I don't think we're putting him back there again, this is the future.
Of all the things to be outraged over... satellites provide extremely valuable services and are pretty near harmless. There's the pollution from the launches, some uncertain concern over putting materials into the upper atmosphere when they reenter, and that's about it. The thing people complain about most is that they get in the way of photographs of the starts. Which is annoying, but also seems to be easily worked around, and is pretty small potatoes compared to planet-wide communications. Your neighbor operating a leaf blower with a dirty two-stroke engine is harming you more than these satellites are.
Makes perfect sense.
https://en.wikipedia.org/wiki/Moir%C3%A9_pattern
* https://satellitemap.space
* https://platform.leolabs.space/visualization