9

Can the ISS be seen clearly with the naked eye at dawn?

I think that it passed over my location, and I barely saw the 4 solar "wings" as well, but I'm not sure of the last part, because people say that it appears only as a dot. I've seen it from Cairo, Egypt and the sky was super clear.

uhoh
  • 148,791
  • 53
  • 476
  • 1,473
Mohamed Gamal
  • 91
  • 1
  • 4
  • I don't know enough about this topic to make this an answer. Perhaps somebody else can improve it and make it an answer. But the atmosphere can magnify objects.

    I'm sure everybody has seen the moon look much larger than it normally does on occasion. https://en.wikipedia.org/wiki/Moon_illusion

    I haven't heard of this happening with the space station or any other satellites before, and it seems like it is typically when it is near the horizon, not directly overhead.

     – Brian Aug 28 '18 at 06:37
  • 2
    @Brian As the Wikipedia page you linked to explains, the Moon illusion is purely psychological. It's not really magnified by atmosphere or anything else. – Moyli Aug 28 '18 at 08:21
  • 2
    I'm no expert on visual perception, but I'm pretty sure what we "see" is as much a part of the brain's processing as the purely "optical" phenomena. To me, it feels possible – especially if you are more than passingly aware of what the ISS looks like (more so if you were "expecting" to see it) – that if (optically) you saw anything other than a perfect circle of light, your brain "filled-in" what it knows the ISS looks like and so you "perceived" the wings much more clearly than would be physically possible. – TripeHound Aug 28 '18 at 11:47
  • @Moyli Whoops, that might have been the wrong article. I had been reading one article talking about atmospheric refraction and magnification. – Brian Aug 28 '18 at 15:28

3 Answers3

12

According to in-the-sky.org, ISS was visible from Cairo at about 4:30 am August 28 2018. It's unlikely that you actually saw its shape, however; it should be nothing more than a bright fast-moving star to the naked eye.

Russell Borogove
  • 168,364
  • 13
  • 593
  • 699
  • I saw solar wings and that was clear for me that i couldn't believe myself, but if it wasn't the iss then what was it ? A satellite maybe ? It's shape was too likely the iss – Mohamed Gamal Aug 28 '18 at 05:46
  • 1
    Any other satellite would show even less detail. What time exactly did you see it? – Russell Borogove Aug 28 '18 at 06:06
  • 8
    @MohamedGamal the ISS is about 400 km away from you when it is overhead, and it is about 100 meters wide. That's a ratio of 4000:1. If you had a drawing of the ISS that was 1 centimeter wide, you can stand 40 meters away from it and judge if you can resolve it or not. If that does't work, then that's your answer. Since the human eyes are not perfect, a point of light will appear to have some spikes or other structures due non-uniformities in the structures of the eyes. This may be why the idea of "star shape" has points, even though real stars don't. – uhoh Aug 28 '18 at 06:06
  • Almost 5:30 am. – Mohamed Gamal Aug 28 '18 at 06:09
  • 1
    I know the idea is impossible, but I can't figure out what I saw. That wasn't a shape of a plane. And ISS couldn't be that close I know – Mohamed Gamal Aug 28 '18 at 06:11
  • 6
    While resolving 4000:1 is not possible to average human eyesight, it's not out of range of capabilities of people with exceptional eyesight. Especially that ISS is a very high-contrast object when visible. Standard 20/20 eyesight allows to resolve letters of 5 arc-second visual angle - reading the 4th from the bottom line on the eye chart at 6 meters. ISS would be 0.85 arc-second - so you would need to be able to read out the manufacturer's "small print" in the corner. I knew one person who had eyesight like that - as a kid. – SF. Aug 28 '18 at 07:49
  • @SF I'm not pretending or admiting that it was the ISS, I saw a thing and I'm asking about it. No need to this language. – Mohamed Gamal Aug 28 '18 at 10:18
  • 6
    @MohamedGamal: Not sure what you thought I implied. Human eyesight worsens with age, starting very early, so it's not unusual for children to have extremely good eyesight; adults with eyesight of this quality are more rare, but hey, if you do have a very good eyesight, it's possible you recognized the ISS. Otherwise, it might be e.g. three airplanes formation-flying... – SF. Aug 28 '18 at 10:21
3

There is a good conversation about this over here: Can I see the ISS from the surface with the naked eye?

Based on that conversation it seems unlikely that you would be able to see the solar wings with your naked eye.

Head Pancakes
  • 126
  • 2
-2

It sounds like a drone. Those can be shaped similar to the ISS.

amara
  • 143
  • 3
  • Hi amara that could be right, but as currently written this is really a comment, not a good Stack Exchange answer. I'd recommend you either expand it into a proper answer, or delete here and post instead as a comment. – uhoh Aug 30 '18 at 02:01