Finally can we read headline of newspaper from space by telescope ?

[kos]

Once upon a time there was exaclty the same question in some other forum but the answers werent strongly supporting either both sides ? What about bluring. Atmospherical seeing may be the hugest problem in the area. What about gravity. Problems may be with staying over particular point as earth rotates ? I dont know. Leave all to you ?

[Airbrush]

It depends on how big the headlines are. Spy satelites can read license plates from space, right? That is about as large of print as huge, one-word headlines in a newspaper.

Edited April 13, 2016 by Airbrush

[Enthalpy]

Newspaper headlines being an ambitious goal, the satellite would be near to Earth, and then it makes an orbit in 96min or slightly less, much faster than Earth's 23h56min rotation, and there is no means to keep the satellite over the same Earth location. It's so for every low-orbit satellite. They take a picture when they fly over the location of interest. More satellites permit to wait less.

 

I suppose - but am not completely sure - that blurring is sometimes a limit. Turbulence occurs at low altitude, under 17km - let's say around 8km - and at locations bad for astronomy it's like 1 arcsecond, which would blurr the imaged target by 39mm. Though, other sites are better, and also this blurring is mainly a global move of the image; since Earth observation gets strong light from the Sun, simply a short exposure improves it. More refined methods exist, I feel they'd be difficult on a moving satellite, but such projects have money. So, yes, blurring is a difficulty.

 

The resolution would be hard and expensive to achieve. A Keyhole is approximately the biggest that present launchers can put in orbit. It's main mirror is suposed to have 2.4m diameter, and it uses already the minimum altitude to achieve an estimated 75mm resolution. 7.5mm resolution for huge (40mm?) newspaper headlines would demand a D=24m mirror which looks impossible.

 

Beware, though, that Sapiens think. Violet or near-ultraviolet light would reduce the need to D=12m. The aperture can be synthesized from several smaller mirrors as on the James Webb Space Telescope. All that would be a huge effort for usually detrimental goals, but money exists precisely for such goals.

 

My interrogation would be: why? The resolution of Google Earth is already better than I need. Good enough for agriculture, home planing... The military need to see armoured vehicles, boats and aeroplanes, for which present images already tell the model.

[kos]

My topic has started from the idea untill I read about alien astarunats watching earth 65 millions yeats away seeing dinosaurs . Everyone told that it is absolutly possible to see them and birds and nature theese times. But I said to myself wait a minute do they know something about bluring adaptive optics and the greatest challenge of atmosphere as a best constrain over the wish of aliens to spot young earth

What is the ultimate thing reasonably small ,smallest actually that today technology in a nice weather can see CLEARY from space?

[Airbrush]

"...On 28 August 2013, it was thought that "a $1-billion high-powered spy satellite capable of snapping pictures detailed enough to distinguish the make and model of an automobile hundreds of miles below"^[6] was launched from California's Vandenberg Air Force Base..."

 

https://en.wikipedia.org/wiki/Spy_satellites

 

If this is true then maybe, if the newstand is facing the perfect direction with good lighting for the spy satellite, and the headlines are very big, then it may be possible.

Edited April 14, 2016 by Airbrush

[Strange]

My topic has started from the idea untill I read about alien astarunats watching earth 65 millions yeats away seeing dinosaurs . Everyone told that it is absolutly possible to see them and birds and nature theese times. But I said to myself wait a minute do they know something about bluring adaptive optics and the greatest challenge of atmosphere as a best constrain over the wish of aliens to spot young earth

What is the ultimate thing reasonably small ,smallest actually that today technology in a nice weather can see CLEARY from space?

 

If you are talking about that sort of distance, then we can just about see some planets. The idea of being able to see life forms on those planets is pure science fiction.

https://en.wikipedia.org/wiki/List_of_directly_imaged_exoplanets

[imatfaal]

"...On 28 August 2013, it was thought that "a $1-billion high-powered spy satellite capable of snapping pictures detailed enough to distinguish the make and model of an automobile hundreds of miles below"^[6] was launched from California's Vandenberg Air Force Base..."

 

https://en.wikipedia.org/wiki/Spy_satellites

 

If this is true then maybe, if the newstand is facing the perfect direction with good lighting for the spy satellite, and the headlines are very big, then it may be possible.

 

Nah - look at Enthalpy's calculations above. You are talking a 10 metre mirror even at the blue/ultraviolet end of the spectrum to get down to around 1cm resolution (that means that you cannot tell the difference between two lines 1 cm apart and one line). That would be over four times the size of Hubble.

 

There are pictures from KH11 satellites on the Wikipage - they are amazing for a satellite photo but nothing like being able to read news print; or even tell a ford focus from a vauxhall astra. BTW - it will also be doing 20-30000 km/h as well so following the car on the satellite image etc that they do in movies is fairly unlikely (ie hollywood nonsense)

[kos]

Let's imagine that constructing the telescope for our needs is done. My question is about atmospherical seeing since it has nothing to do with the size of the lenses or with the technology involved. Despite best attemps I suppose that there would be no way dealing with random motion of gases around the earth wich can make dispersion ,reflection , difraction and depolarization of light rays in uncountable limit because it is all random. So for a remote astraunats somewhere in deep space on their remote planet looking to earth even with telescope with the size of milky way or even bigger there will be no way to unblur the taken picture from the atmospherical seeing. Any attemp to catch clear photo would be detronized by the random motion of great content of gase ! If I'm wrong disprove me !

Edited April 14, 2016 by kos

[Strange]

I think that if they had the technology to build telescopes of that scale, then advanced filtering would be simple for them. (Bearing in mind this is pure fiction.)

[kos]

On the contrary I think it s gonna be impossible !

[Enthalpy]

Blurring is often worse than the 1 arcsecond I took, because this holds for a bad observation site during nighttime. Daytime makes it worse.

 

How much can be filtered out? Unclear to me. Adaptive optics makes miracles for astronomy. From before-after comparisons, I'd say they gain a factor of 10. That would bring 1arcsecond blurring from 40mm to 4mm at the target, and then big headlines get clear.

 

Notice that this blurring in mm at the target doesn't worsen with the observer's distance.

[kos]

What is the blurind of casual day with normal sunny weahter?

[Enthalpy]

I don't know.

 

I only remember that when observing Venus in a small refractor, blurring increases very quickly as the Sun heats the ground still minimally, so in a sunny day it would be brutal, many many arcseconds.