Astronomy / Space Max Apparent magnitude for human eye?
- Thread starter Orbitalai
- Start date
Had a look through some Astronomical forums. Even on these, the information is a little vague.
The earths atmosphere lets in around 90% of visible light, so logically you should see 10% more stars in space. There is a problem though, the level of night vision.
Humans take between 15 minutes and a hour to gain full night vision, which would allow you to see a much greater numbers of stars. In a lit up cockpit, it's unlikely you would have any night vision at all.
Yep, is why I have mentioned several times on these forums, that a switch for cockpit displays would be nice.
Yep, is why I have mentioned several times on these forums, that a switch for cockpit displays would be nice.
I really should read back on the forums more, but I'm lazy.
Turning the lights out for 15 minutes plus seem abit extreme though.
This video is the best answer I've found on the topic. It suggests that the atmosphere is pretty transparent to light in the visible spectrum (the light it blocks is mostly UV, etc.) Something like 98% of visible light gets through assuming it's travelling through pure atmosphere (i.e. not much water vapour or air-borne dust in the way).
Probably the difference between the faintness of stars you could see in space versus on Earth would be less than the differences you'd find between different people. It's plausible that you might have one person in the Atacama desert and another on the Moon, and still find that the person in the Atacama desert can pick out fainter stars, just because their vision is better suited. What would be different is that the stars on the moon would be crisper, and wouldn't twinkle, due to the lack of turbulent atmosphere.
I could be wrong though. The internet is not a good place to check facts, and I'm struggling to validate that 98% figure.
Probably the difference between the faintness of stars you could see in space versus on Earth would be less than the differences you'd find between different people. It's plausible that you might have one person in the Atacama desert and another on the Moon, and still find that the person in the Atacama desert can pick out fainter stars, just because their vision is better suited. What would be different is that the stars on the moon would be crisper, and wouldn't twinkle, due to the lack of turbulent atmosphere.
I could be wrong though. The internet is not a good place to check facts, and I'm struggling to validate that 98% figure.
Ah, thanks. Expected a higher difference actually.
Me too.
Probably writing an academic paper, and almost certainly not posting stuff up on the internet. One of the first articles I read claimed that you can't see stars from space! Moonfaker propaganda.
It's worth noting that there is a much bigger difference when you're talking about stargazing near light pollution. The only time I've really seen the sky in its full majesty was a holiday in the Kalahari desert. It really was much more impressive than you ever see it back in England.
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I will never forget the desert night sky - stunning! I'm a townie now, and the light pollution is atrocious!
Middle of the North Atlantic on a darkened ship. The Milky Way is a sight to behold.
The magnitude system comes from the Ancient Greeks, and is unaffected by light pollution or crappy weather . The definition of magnitude has changed a bit, but the original system arranged visible stars into 6 magnitudes; so it's no surprise that the faintest visible stars have magnitudes of about 6 . By the way, the modern values are corrected for atmospheric effects, so they would be the same in space.
. The definition of magnitude has changed a bit, but the original system arranged visible stars into 6 magnitudes; so it's no surprise that the faintest visible stars have magnitudes of about 6 . By the way, the modern values are corrected for atmospheric effects, so they would be the same in space.