<p>Yes, absolutely! The performance of <em>any</em> telescope depends on its diameter. A larger instrument not only collects more light, but also provides better resolution than a smaller instrument. The resolution limit is calculated from:</p>
<p><span class="math-container">$R_{arcsec}\ = {1.22\ \lambda \over D_{mm}}$</span></p>
<p>whereas limiting magnitude is calculated from</p>
<p><span class="math-container">$L_{mag}\ =\ 2.5\ +\ 5\ log\ D_{mm}$</span></p>
<p>I <em>suppose</em> there are eventual limits to <span class="math-container">$R_{arcsec}$</span>, but I have never heard of any. As for limiting magnitude, as it’s a logarithmic formula, it grows very slowly as <span class="math-container">$D_{mm}$</span> increases, but a larger telescope is still a gain.</p>
<p>The whole thing is to balance <span class="math-container">$R_{arcsec}$</span>, <span class="math-container">$L_{mag}$</span>, and $$$, of course!</p>

CC BY-SA 4.0
2020-12-25T21:58:14.483Z
not necessarily a limit but might require correction: [Can weak gravitational lensing or microlensing-induced wavefront distortion limit resolution of absurdly large aperture telescopes?](https://astronomy.stackexchange.com/q/29090/7982)
uhoh
CC BY-SA 4.0
2020-12-25T21:14:52.733Z
2020-12-25T21:14:52.733Z
Pierre Paquette
<p><a href="https://youtu.be/R8KlX2OFg-s" rel="nofollow noreferrer">Watching this video</a> describing the &quot;next generation&quot; space telescope, it seems like the biggest mirror will be ~6 meters in diameter.</p>
<p>Theoretically, if a telescope was built in space instead of shipping it pre-built, and the mirror was, not a few meters, but a few kilometers, (and whatever other important aspects of a space telescope that a novice like myself has no idea about, multiply them by a few orders of magnitude) would it provide benefits proportional to the size difference?</p>

CC BY-SA 4.0
2020-12-25T21:55:22.970Z
That is an incredible video, wow! I think it can serve as the basis of many many new questions here. *Thanks for the link!*
uhoh
CC BY-SA 4.0
2020-12-26T00:11:48.007Z
here's another already: [How do HabEx's internal coronagraph and external starshade work together and complement each other? What is it that each can do that the other can't?](https://astronomy.stackexchange.com/q/40601/7982)
uhoh
<telescope><space-telescope>
Limits of space telescope?
rodrigo-silveira
# Limits of space telescope?

(Asked by: username_0 on 2020-12-25)

[Watching this video](https://youtu.be/R8KlX2OFg-s) describing the "next generation" space telescope, it seems like the biggest mirror will be ~6 meters in diameter.

Theoretically, if a telescope was built in space instead of shipping it pre-built, and the mirror was, not a few meters, but a few kilometers, (and whatever other important aspects of a space telescope that a novice like myself has no idea about, multiply them by a few orders of magnitude) would it provide benefits proportional to the size difference?

**Tags:** telescope, space-telescope
> **Comments:**
> **username_1**: That is an incredible video, wow! I think it can serve as the basis of many many new questions here. *Thanks for the link!*  
> **username_1**: here's another already: [How do HabEx's internal coronagraph and external starshade work together and complement each other? What is it that each can do that the other can't?](https://astronomy.stackexchange.com/q/40601/7982)  

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## 1 answers

### Answer by username_2 on 2020-12-25. Score: 3 | Accepted answer

Yes, absolutely! The performance of *any* telescope depends on its diameter. A larger instrument not only collects more light, but also provides better resolution than a smaller instrument. The resolution limit is calculated from:

$R\_{arcsec}\ = {1.22\ \lambda \over D\_{mm}}$

whereas limiting magnitude is calculated from

$L\_{mag}\ =\ 2.5\ +\ 5\ log\ D\_{mm}$

I *suppose* there are eventual limits to $R\_{arcsec}$, but I have never heard of any. As for limiting magnitude, as it’s a logarithmic formula, it grows very slowly as $D\_{mm}$ increases, but a larger telescope is still a gain.

The whole thing is to balance $R\_{arcsec}$, $L\_{mag}$, and $$$, of course!

> **Comments:**
> **username_1**: not necessarily a limit but might require correction: [Can weak gravitational lensing or microlensing-induced wavefront distortion limit resolution of absurdly large aperture telescopes?](https://astronomy.stackexchange.com/q/29090/7982)  

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