How far can the best telescope see?

  • Stargazing
  • Thread starter siddharth23
  • Start date
  • Tags
    Telescope
In summary, the distance at which a telescope can clearly see objects is not measured in light years, but rather in brightness. This is due to the fact that exposure time and resolution play a larger role in determining how well we can see objects, rather than the telescope itself. The Hubble Space Telescope, being larger and in space, has a greater advantage in terms of resolution. However, its ability to see objects clearly is still limited by factors such as light pollution and atmospheric blurring. The Andromeda Galaxy, despite being over 2 million light years away, is visible to the naked eye due to its brightness, while Pluto, within our own solar system, cannot be seen without the aid of a telescope. With advanced technology, we
  • #1
siddharth23
249
26
Using the best technology available, how far can you see things clearly? As in how many light years?
 
Astronomy news on Phys.org
  • #2
We don't use distance as a measure of how well a telescope can see. Instead we use brightness. A super bright object 5 billion light years away can be MUCH easier to see than a very dim object within our own solar system.

Also, how far a telescope can see has little to do with the telescope itself and more to do with how much exposure time you can get to beat down the signal to noise ratio in the images. Given enough exposure time, my 8 inch telescope could see the same objects that the Hubble Space Telescope can. The difference is that the HST has far more resolution thanks to its larger size along with the advantage of being in space instead of on the ground where seeing ability is limited by light pollution and blurring due to the atmosphere.
 
  • Like
Likes 1 person
  • #3
Here's a perfect example of what I was saying.

The Andromeda Galaxy is a little over 2 million light years away and is visible to the naked eye from practically the entire world.

Pluto is within our own solar system and cannot be seen by the naked eye. (The eye performs the same function as a telescope, so I'm using it as a comparison)
 
  • #4
We can see the CMB, how far is that?
 
  • #5
On the other hand, we have difficulty resolving ordinary stars in the Magellanic clouds.
 
  • #6
siddharth23 said:
Using the best technology available, how far can you see things clearly? As in how many light years?

When you say "how far", I immediately think of the Hubble Deep Field and the Ultra-deep field. Are you aware of these two images?
 
  • #7
Isn't "how far" a little bit misleading? I could possibly say that my vision with bare eye is infinite, however what I can actually observe and identify - that is something completely different.
 
  • #8
bluecore said:
Isn't "how far" a little bit misleading?

Yes, just as we explained above, asking "how far" a telescope can see is meaningless.
 
  • #9
My bad, I didn't know that. I got curious when I saw an image in which there appeared to be many stars. But the explanation said many of them were actually galaxies.

Given enough clarity and exposure, is it possible to observe the happenings in, say, Andromeda?
 
  • #10
jackmell said:
When you say "how far", I immediately think of the Hubble Deep Field and the Ultra-deep field. Are you aware of these two images?

No I haven't. I'll check them out.
 
  • #11
siddharth23 said:
Given enough clarity and exposure, is it possible to observe the happenings in, say, Andromeda?
Depends on what "the happenings" are.
 
  • #12
Like volcanos on the surface of a planet. Just a crude example. Something like that.
 
  • #13
No, the resolution of our telescopes is a function of their size, due to the physics of how optics work. They have nowhere close to enough resolution to resolve planets, much less surface features in Andromeda.
 
  • #14
siddharth23 said:
Using the best technology available, how far can you see things clearly? As in how many light years?

About 5.8 billion light years. That corresponds to a red shift of about 1.64. We can see light from objects which has been traveling for longer but those objects were closer when the light was emitted.
 
  • #15
GeorgeDishman said:
About 5.8 billion light years. That corresponds to a red shift of about 1.64. We can see light from objects which has been traveling for longer but those objects were closer when the light was emitted.


probably a bit hopeful there ;)
I would suggest its substantially less than that
yes we can see objects at several billion lightyears. but resolving ones out to a few 100 million ly's

note what the OP said ... "how far can you see things clearly? "
Russ's response gives a better idea of resolution problems

Dave
 
  • #16
siddharth23 said:
Like volcanos on the surface of a planet. Just a crude example. Something like that.
The resolution of our best telescopes is good enough to:

- see some features of Pluto (of the size of ~500km), but nothing in detail
- see a few of the biggest and closest stars as a disk
- see some planets (as spots without any features) around stars nearby
- track individual stars in the whole galaxy
- observe some individual bright stars in the Andromeda galaxy

To see features on planets around other stars, you would need a telescope with a diameter of (at least) hundreds of kilometers.
 
  • #17
davenn said:
probably a bit hopeful there ;)
I would suggest its substantially less than that
yes we can see objects at several billion lightyears. but resolving ones out to a few 100 million ly's

note what the OP said ... "how far can you see things clearly? "
Russ's response gives a better idea of resolution problems

"clearly" is a qualitative term. The original question suggests that better telescopes can see farther but that is not always the case. We have telescopes that can image objects at z=1.6 and while better telescopes may improve the resolution at all ranges, they can't allow us to see farther.

Essentially, the only sensible measure of resolving power is angular and range becomes academic.
 

1. How far can the best telescope see?

The best telescopes on Earth are currently capable of seeing objects up to 13 billion light years away. This means that the light from these objects has traveled for 13 billion years to reach Earth, giving us a glimpse into the early universe.

2. What determines the distance a telescope can see?

The distance a telescope can see is determined by several factors, including the size and quality of the telescope's primary mirror, the atmospheric conditions, and the sensitivity of the telescope's detectors. The larger and more precise the primary mirror, the further the telescope can see.

3. Can telescopes see beyond our own galaxy?

Yes, the best telescopes are capable of seeing objects beyond our own Milky Way galaxy. In fact, many of the objects that we can see with telescopes are located in other galaxies, giving us a better understanding of the vastness of the universe.

4. Has the distance that telescopes can see increased over time?

Yes, the distance that telescopes can see has increased over time as technology and techniques have improved. The best telescopes today are able to see much further than the telescopes of the past, allowing us to see deeper into the universe and further back in time.

5. Are there telescopes in space that can see further than Earth-based telescopes?

Yes, there are telescopes in space that are able to see much further than Earth-based telescopes. These include the Hubble Space Telescope, which has a clear view of the universe without the interference of Earth's atmosphere, allowing it to see objects up to 13 billion light years away.

Similar threads

  • Astronomy and Astrophysics
Replies
25
Views
1K
  • Astronomy and Astrophysics
Replies
6
Views
2K
  • Astronomy and Astrophysics
2
Replies
36
Views
1K
  • Astronomy and Astrophysics
Replies
12
Views
1K
  • Astronomy and Astrophysics
Replies
7
Views
2K
  • Astronomy and Astrophysics
4
Replies
125
Views
4K
  • Astronomy and Astrophysics
Replies
2
Views
2K
  • Astronomy and Astrophysics
Replies
9
Views
2K
  • Astronomy and Astrophysics
Replies
1
Views
1K
  • Astronomy and Astrophysics
Replies
2
Views
757
Back
Top