Can Telescopes Show Recognizable Reflections at Long Distances?

In summary, there is a limit on resolution for a single aperture due to the Rayleigh Criterion, which states that two objects cannot be resolved if their separation is less than the ratio of the wavelength of light to the size of the opening. This means that a good SLR camera with a 2 cm aperture cannot resolve two dots half a mile away unless they are more than 2 cm apart. Additionally, atmospheric conditions such as temperature and haze can also affect long range sight pictures. The limitations of telescopes include the fact that they are limited by the atmosphere and can only detect objects that reflect light, while the majority of mass in the universe is not visible.
  • #1
Newai
32
1
Looking over CSI's "zoom and enhance" silliness, are there telescopes that could show a recognizable reflection off a small object, even a good mirror, at a mile or so? What range limits are there for reflection using high-powered scopes?
 
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  • #2
There are a few limiting factors when it comes to the lenses involved, but there is an absolute limit on resolution for a single aperture.

It's called the Rayleigh Criterion: basically, due to the diffraction of light as it passes through the opening of a camera or telescope, you cannot resolve two objects (that is, you can't tell there are two and not one single object) if the ratio of their separation over the distance to the objects is less than the ratio of the wavelength of light over the size of the opening.

That ratio s/d (object separation over distance to the object) also equals the sine of their angular separation, so the Rayleigh criterion is usually written as
sin theta = 1.22 x lambda/ D

The 1.22 is a factor thrown in for circular openings.

So a good SLR type camera, with about a 2 cm aperture with f-stop open wide, cannot possibly resolve two dots half a mile away unless they are more than 2 cm apart, and that's with a perfect lens.
 
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Thank you.
 
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...also assuming the atmosphere is perfectly still and of even temperature distribution, which it isn't.
 
  • #5
Russ nailed it above. Air temp and haze (moisture/dust/pollution) often mess with any long range sight picture.
 
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  • #6
The biggest limitations of telescopes is that
1. You're looking through the atmosphere
and
2. You're only being up objects that reflect light, where the large majority of mass in the universe is not visible.
 

FAQ: Can Telescopes Show Recognizable Reflections at Long Distances?

1. What is the maximum distance a telescope can see?

The maximum distance a telescope can see depends on several factors, including the size and quality of the telescope's optics, the sensitivity of its detectors, and atmospheric conditions. Currently, the most powerful telescopes on Earth can see objects up to about 13 billion light years away.

2. How much detail can a telescope resolve?

The level of detail a telescope can resolve is primarily determined by its aperture, or the diameter of its primary lens or mirror. The larger the aperture, the finer the detail a telescope can capture. However, other factors such as atmospheric turbulence can also limit a telescope's resolving power.

3. Can telescopes see through clouds and other obstacles?

No, telescopes are limited by the same obstacles that humans are when it comes to seeing through clouds, fog, and other atmospheric disturbances. However, some telescopes, such as those that operate in the radio or infrared spectrum, can see through dust and gas clouds that are opaque to visible light.

4. Can telescopes see in all directions at once?

No, telescopes are limited by their field of view, which is determined by the size and shape of their optics. Some telescopes have a narrow field of view, allowing them to zoom in on small areas of the sky in great detail, while others have a wider field of view, allowing them to capture larger portions of the sky at once.

5. Are there any technological limitations to telescope design?

Yes, there are some technological limitations to telescope design, such as the maximum size and weight that can be supported by a telescope's structure, the precision of its optics, and the sensitivity of its detectors. However, advancements in technology and engineering continue to push these limitations further, allowing for more powerful and advanced telescopes to be built.

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