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Space

SpaceX's Starlink Satellites Accused of 'Photo-Bombing' Shots of Comet Neowise (livescience.com) 112

"Comet Neowise has been the brightest and most visible space snowball in a generation, but it's also the first naked-eye comet to visit us in the new era of satellite mega-constellations like SpaceX's Starlink," writes CNET.

"In just the latest episode of Starlink 'trains' irritating astronomers, a number of images have been circulating of the satellites photo-bombing Comet Neowise glamour shots..."

Live Science explains: Visible just above the horizon right now, the comet appears faint and small to the naked eye, but can be seen clearly through cameras with long, telephoto lenses. Usually, when photographers capture objects like this in the night sky they use long exposure times, leaving the camera aperture open to collect light over the course of several seconds. But now comet-chasers report that a new fleet of SpaceX's Starlink satellites is leaving bright smears across their NEOWISE snaps, as the shiny orbiters streak through their frames during long exposures.
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SpaceX's Starlink Satellites Accused of 'Photo-Bombing' Shots of Comet Neowise

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  • by dmay34 ( 6770232 ) on Saturday July 25, 2020 @03:41PM (#60331297)
    There is actually a pretty short window of time, typically just before sunrise and just after sunset when the Star Link stats will problematically reflect the sun. Needless to say, this isn't generally the best time for astronomy anyways. But, if you just wait a few minutes after sunset then the sats won't be able to problematically reflect sunlight. Second, this photographer was using a pretty wide angle lens and then specifically composited his images WITH the sats to make his shocking picture. It's pretty easy to composite these kinds of sat trails out of pictures. I honestly kinda think the guy was trying to get a shocking looking photo.
    • Re: (Score:1, Troll)

      by Kohath ( 38547 )

      But if they waited a few minutes until the satellites were hidden they wouldn't be able to declare themselves victims and wouldn't be able to get media coverage.

      • by slazzy ( 864185 )
        Correct, while thousands of people took great photos of this Comet, only one person got famous from his "ruined photo". He's either among the worlds worst photographer/astronomers or quite a genius at getting free publicity. I say congratulations on the free publicity.
      • by Solandri ( 704621 ) on Sunday July 26, 2020 @01:12AM (#60332271)

        But if they waited a few minutes until the satellites were hidden they wouldn't be able to declare themselves victims and wouldn't be able to get media coverage.

        It is not just "a few minutes." Depending on the right ascension of what you're trying to photograph, it can be most of the night.

        While each individual satellite obstructs the comet (or any point in the sky you wish to photograph) for just a few minutes (actually probably a few seconds), you have to remember that there are tens of thousands of satellites planned. So the time a single satellite is in the right (wrong) location isn't that important. The figure you want is how long any one of those satellites could be lit by the sun while the observer is in darkness.

        Starlink satellites [wikipedia.org] orbit between 335-1325 km, with a common average stated as 550 km. Range of visibility is a simple line of sight calculation [wikipedia.org]. Although we'll use the angle rather than a distance like in the diagram.

        If the sun as at the left, the diagram represents the furthest a satellite can be on the dark side of the Earth, and still be lit by sunlight.

        • arccos ( 6570 km / (6570 km + 335 km) ) = 17.9 degrees
        • arccos ( 6570 km / (6570 km + 550 km) ) = 22.7 degrees
        • arccos ( 6570 km / (6570 km + 1325 km) ) = 33.7 degrees

        Double it since the furthest angle at which an observer on the dark side can see this satellite barely lit by sunlight is symmetric (just flip the triangle around the hypotenuse). Double it again since it happens at sunrise and at sunset. So:

        • With no satellites, the hemisphere of guaranteed darkness is 180 degrees
        • With satellites at 335 km, the cone of guaranteed darkness (no Starlink satellites visible) is (180 - 4*17.9) = 108.4 degrees, or a loss of 4h 46m of night time from a 12 hour night. Or a loss of 39.8% of night.
        • With satellites at 550 km, the cone of guaranteed darkness shrinks to (180 - 4*22.7) = 89.2 degrees, or a loss of 6h 3m of night time from a 12 hour night, or 50.4%
        • With satellites at 1325 km, the cone of guaranteed darkness shrinks to (180 - 4*33.7) = 45.2 degrees, or a loss of 8h 69m of night time from a 12 hour night, or 74.9% of night. Note that satellites at the higher altitudes will be dimmer due to the greater distance, so will interfere less even if they are visible.

        This doesn't mean all of the sky is obscured for that long. These times are how long *some* of the sky is obscured by satellites. If you use nautical or astronomical twilight [weather.gov] (12 and 18 degrees after sunset / before sunrise respectively), subtract 24 degrees and 1h 36m from these figures (nautical twilight), or 36 degrees and 2h 24 min (astronomical twilight).

        Basically, with a full Starlink satellite constellation in orbit, any photo of anywhere in the sky you take at sunset can have Starlink satellite streaks in them. A North-South line will sweep from East to West, eventually crossing the Western horizon ("Starlink sunset"). Photos of anything to the west of this line can suffer from sunlight flaring off of Starlink satellites. "Starlink sunset" will occur at 2h 23m after sunset (335km altitude), 3h 2m after sunset (550 km altitude), or 4h 30m after sunset (1325 km altitude).

        The same thing will happen in reverse before sunrise. A line will sweep from east to west starting from 2h 23m to 4h 30m before sunrise. Any photos taken to the east of this line can suffer from sunlight flaring off of Starlink satellites.

        So we're not talking about just having to wait a few minutes to be clear of the flares. We're talking most of the night.

    • by Applehu Akbar ( 2968043 ) on Saturday July 25, 2020 @04:13PM (#60331363)

      This is similar to the trick of photographing down the length of a city street with a long lens to make the signage on the street look overcrowded and ugly. Pictures can lie as easily as words.

      • This is similar to the trick of photographing down the length of a city street with a long lens to make the signage on the street look overcrowded and ugly.

        Not really. The photograph was accidental: the photographer was not trying to capture a picture of the satellites he was trying to photograph the comet. Also, this could have been largely avoided if Mr Musk had bothered to cover his satellites with an anti-reflective coating.

        • The next generation is already launching with vanta black.

          Wait you want him to go up there and paint all the existing ones with spray paint too?

          • Well, yes, that could be one reasonable expectation. This sort of thing should have been thought of before the first wave were launched. It is similar to the litter problem in the oceans, or the other environmental pollution with antibiotics - all kinds of exciting new products being developed for one intended use, without thinking of the other consequences.
            • by Necron69 ( 35644 )

              It is literally NOTHING like pollution in the oceans. A far better analogy is an airplane crossing the sky while you want to take a picture. I don't hear people freaking out about that.

        • You, sir, are an idiot and a liar. It was a composite of 19+ long exposure shots with all other artifacts except Starlink digitally removed. Had those same processes been used on a single shot you would have only seen the night sky and the comet.

    • No, he wasn't trying to get a shocking looking photo. He says he got it without trying. What he is trying to create is awareness of the growing amount of trash and pollution by mankind that has gone beyond the atmosphere and into orbit. Ground-based astronomy is important to get people interested in astronomy and for them to become active. To say we're not losing something of value here is ignorant.

      But to be honest, I don't see this ever changing. Mankind has been exploiting about everything imaginable, and

      • by dmay34 ( 6770232 )
        Listen, I love astronomy. I have a 4-in cassegrain Celestron that I use to teach astronomy classes. I've taught astronomy classes using StarryNight and my little travel scope all over the world, college campuses and rural villages in northern Zimbabwe. My favorite thing in the entire firggin' world to do is to watch a person see Saturn with their own eyes for the first time. I get it. But I also understand the value of the internet and communication. I'm okay trading 15 minutes of less than ideal observat
        • by HiThere ( 15173 )

          I have a lot of doubt that StarLink will ever be of significant value to those living in cities. The reason is signal congestion. Too many signals in too small an area. Where there are dense populations cell networks, and even 5g, are better answers. (5g is better because the smaller cell size allows more signals / unit area|volume.)

          • by dmay34 ( 6770232 )
            Right.... But you can't do astronomy in cities either. We've made this trade off before.
            • One can do astronomy in cities, only not as well as one likes, but this is true for any place on Earth. You can certainly see the Moon and some of the planets with only your bare eyes. Binoculars and a small telescope are then the next step. It's all astronomy.

              • by dmay34 ( 6770232 )
                Yes, but if you are trying to do astronomy in cities then Starlink isn't going to be an issue for you, is it?
                • Yes, it is. What makes you think it wouldn't be?

                  I don't know right now if one can see the Starlink satellites with the naked eye, I suppose one can, but I have seen many other satellites with the naked eye in cities. That is not in the city centres with all the heavy street lights and traffic, but the suburban areas. When you then do time lapse and long exposure photography can you get a lot of satellites.

                  But if you think this is all just peanuts then simply wait until all 42,000 Starlink satellites are in

                  • Yes, it is. What makes you think it wouldn't be?

                    Um. The fact that if the only thing you can see is the moon, a satellite isn't going to have any impact on your ability to continue viewing it?

                    • Like I said above, the moment you start doing exposure photography will it get really annoying. You first need to get an opening in the clouds, you then have to combat light pollution and now this.

                    • Oh darn. I'm sorry it's getting harder for you to take pretty pictures. I'll send you some nice ones over my new Starlink internet connection.

          • by Megane ( 129182 )
            And it was never intended to be useful in big cities. Who said it would be? Cities already have plenty of wired options. It also surely needs the kind of sky angle that you don't get in a city unless the antenna is on a flat roof of a tall building.
      • Comment removed based on user account deletion
        • Your only response to an accusation of malice is to cite the accused persons testimony?

          Yes, of course. What grounds do you have to take the accusation serious? Or wait, let me guess ...

    • There is actually a pretty short window of time, typically just before sunrise and just after sunset when the Star Link stats will problematically reflect the sun.

      That may be true but there are also certain objects which are typically also only viewable just before sunrise and just after sunset like Mercury, Venus and comets. Plus, in higher latitudes in the summer you are never that far from sunset or sunrise.

      • by dmay34 ( 6770232 )
        That's true -to a point- but even then it's pretty easy to filter out the streaks and get the shots you are trying to achieve. Heck, I'm pretty sure this is just a standard feature in photoshop.
        • by dmay34 ( 6770232 )
          And seriously, people talk like Elon Musk is the first person to shoot up satellites. This has literally been an "issue" for astronomy forever, and there are actually much bigger and even more reflective satellites up there. It's not that hard to work around them.
    • There is actually a pretty short window of time, typically just before sunrise and just after sunset when the Star Link stats will problematically reflect the sun.

      Funny that's usually the time window when astronomers are actually able to do measurement on comet tails.

      Second, this photographer was using a pretty wide angle lens

      Yeah who would look into space doing wide angle for science [sdss.org], it's clearly just an astronomy thing.

      It's pretty easy to composite these kinds of sat trails out of pictures.

      No it's not. It's quite difficult and even when you do it they leave noise trails. Frames with these kinds of interference are often rejected wholesale if possible both when just taking pretty pictures and when doing actual science so it doesn't mess up the data.

      I honestly kinda think the guy was trying to get a shocking looking photo.

      Honestly I think you've never taken a photo of

  • by AmiMoJo ( 196126 ) on Saturday July 25, 2020 @03:43PM (#60331305) Homepage Journal

    You can see the constellation here: https://www.heavens-above.com/... [heavens-above.com]

    • by Anonymous Coward

      Why would anyone paint the squares red? To see them from the ground?

    • Thanks, that's a very cool visualization.

      I know they're small, but damn it looks like swarm that's constantly *just* avoiding a thousand collisions.

      It must be a nightmare tracking all those orbits.

  • by account_deleted ( 4530225 ) on Saturday July 25, 2020 @04:27PM (#60331393)
    Comment removed based on user account deletion
  • Re: (Score:2, Insightful)

    Comment removed based on user account deletion
    • by pjt33 ( 739471 )

      The story I saw in the Spanish press a few days ago had some of those details: 21st of July, Tenerife, 200mm lens on full frame camera. As to how they know it's Starlink: isn't elimination a sufficient explanation? Can you name any other cluster of satellites big enough to leave that many streaks?

    • by thegarbz ( 1787294 ) on Sunday July 26, 2020 @04:50AM (#60332535)

      The outrage is justified. Let's look at your dismissive comments as to why you're trying to gaslight:

      - There is no information about the camera settings, location or time of capture.
      Not at all relevant. For astronomy pictures there's a very narrow set of camera settings suitable. For actual science the options are even narrower. The time of capture for a comet is incredibly limited given the intensity of their trails is dependent on proximity to the sun meaning that there resulting images will always happen right around the time Starlink satellites are most lit up.

      - The articles linked provide no information about the photographers beyond names associated with the twitter accounts
      I guess the pictures are fake then? Not sure why you think it's relevant to know information about the people. Does that help you discredit them?

      - There are no details about how the satellites were identified as Starlink
      Starlink are the only satellites in a constellation circling the globe which look like this. If you ever see trails like this you're pretty much guaranteed that it's Starlink ... at least until the next company starts flinging hotspots into space. Look here https://www.heavens-above.com/... [heavens-above.com] it may look like random noise until you select one of the constellations. When you do you'll realise Starlink satellites orbit in groups and will leave multiple streaks in your image.

      - Articles and posts like these will not have positive effects on readers.
      Good. Neither does Starlink.

      - For uncritical readers, uninformed outrage will be seeded.
      For critical readers informed outrage will be seeded. You seem to have fallen into a 3rd group that you didn't identify: uninformed reader attempting to deliberately discredit and gaslight.

  • by kbahey ( 102895 ) on Saturday July 25, 2020 @05:54PM (#60331601) Homepage

    I went out to view the comet on July 17th and take pictures using a regular DSLR on a tripod (no sky tracking).

    I took many 6 second exposures, and noticed at least two satellites showing up in some sequences.

  • But now comet-chasers report that a new fleet of SpaceX's Starlink satellites is leaving bright smears across their NEOWISE snaps, as the shiny orbiters streak through their frames during long exposures.

    Comet chasers' inconvenience clearly trumps planet-wide communications. Right?

  • Starlink orbit and locations are not secret .. you can find out the exact time the satellite will be there down to the millisecond.. first off, if you happen to be taking a wide field photo for astronomy .. then don't be an idiot just turn off the camera during the starlink transit. Second, if the satellites were dark it would be worse you may think you're witnessing a giant exoplanet eclipse or something. There are enough satellites in the sky already that you should be doing that anyways.

    • then don't be an idiot just turn off the camera during the starlink transit.

      Maybe don't be an idiot and look up your non secret Starlink orbit, you may realise that it's not actually possible to do what you said in many locations on the planet.

The most difficult thing in the world is to know how to do a thing and to watch someone else doing it wrong, without commenting. -- T.H. White

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