<p>Far from "orbit" some of the longest telescopes in history are:</p>

<ul>
<li>Tubed: "<a href="https://en.wikipedia.org/wiki/Aerial_telescope#Very_long_%22tubed%22_telescopes" rel="nofollow noreferrer">Hevelius' Longest Telescope from Machinae Coelestis</a>" - 150 feet</li>
</ul>

<p><a href="https://i.sstatic.net/yxAOP.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/yxAOP.jpg" alt="Hevelius&#39; Telescope"></a></p>

<ul>
<li>Tubeless: "<a href="https://en.wikipedia.org/wiki/Aerial_telescope" rel="nofollow noreferrer">Huygen's Telescope</a>" - 210 feet</li>
</ul>

<p><a href="https://i.sstatic.net/W1BT9.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/W1BT9.jpg" alt="Huygen&#39;s Telescope"></a></p>

<p>Apparently <a href="https://en.m.wikipedia.org/wiki/Adrien_Auzout" rel="nofollow noreferrer">Adrian Auzout</a> and others made telescopes of from <a href="https://en.wikipedia.org/wiki/Aerial_telescope#Tubeless_%22aerial%22_telescopes" rel="nofollow noreferrer">300 to 600 ft</a> (90 to 180 m) focal length, but I've not found a drawing from the late 1600's of it.</p>

<p>In theory you could have a distant <em>objective lens</em> but either it would need to be huge (costly) or your field of view would need to be extremely narrow (only useful for extremely distant objects). Then there's the cost of stabilizing the lens and maintaining alignment.</p>

CC BY-SA 4.0
2018-07-24T06:45:34.920Z
2018-07-24T06:45:34.920Z
Rob
<p>Speaking in general, telescopes are designed as complete systems from the beginning. It's not generally feasible to improve performance by just adding yet another lens or mirror to the assembly. The reasons for this are not simple to explain, since this is basically the whole theory of instrument design.</p>

<p>Usually you start with a set of requirements (limiting magnitude, angular resolution, linear resolution in prime focus, etc) and with a set of constraints (cost, size, weight, materials).</p>

<p>You settle on a given architecture (newtonian reflector, Ritchey-Chrétien, doublet / triplet / quadruplet refractor, etc), and then start to work out the main parameters: aperture, focal length, etc.</p>

<p>There's an iterative process involving computer aided design to work out the details of each optical element; at each step you need to solve problems such as eliminating internal reflections, etc.</p>

<p>In the end, what you have is the design of the whole optical stack: say a Dall-Kirkham reflector, 1 meter aperture, f/8, with mirrors of whatever radiuses of curvature, etc.</p>

<p>Once that's set in stone, it's hard to change in a major way. Minor upgrades might be possible (add a corrector lens, or a different secondary mirror), but not huge modifications.</p>

<hr>

<p>TLDR: No. Start with a bigger instrument from scratch if that's what you want.</p>

CC BY-SA 4.0
2018-07-23T23:43:56.710Z
2018-07-23T23:43:56.710Z
Florin Andrei
<p>Could a lens or mirror be placed in orbit on the same flight path with other parts to make a telescope or on the horizon of the moon to see farther with the Hubble? </p>

CC BY-SA 4.0
2018-07-24T14:20:04.430Z
I don't think you understand what "amplified" could mean.  The light-collecting ability is limited by the size of the first element. The resolution depends on any number of factors.
Carl Witthoft
CC BY-SA 4.0
2018-07-24T20:26:40.840Z
Orbital telescopes are using mirrors and not lenses. Lenses have various disadvantages: 1) they are weighty 2) their focus for red and blue colors is a little bit different. Professional, HQ telescopes are using practically always mirrors.
peterh
<amateur-observing><photography><hubble-telescope><telescope-lens>
Can a telescope image be amplified to see more by adding distant lenses or mirrors?
Muze
# Can a telescope image be amplified to see more by adding distant lenses or mirrors?

(Asked by: username_0 on 2018-07-23)

Could a lens or mirror be placed in orbit on the same flight path with other parts to make a telescope or on the horizon of the moon to see farther with the Hubble?

**Tags:** amateur-observing, photography, hubble-telescope, telescope-lens

> **Comments:**
> **username_1**: I don't think you understand what "amplified" could mean.  The light-collecting ability is limited by the size of the first element. The resolution depends on any number of factors.  
> **username_2**: Orbital telescopes are using mirrors and not lenses. Lenses have various disadvantages: 1) they are weighty 2) their focus for red and blue colors is a little bit different. Professional, HQ telescopes are using practically always mirrors.  

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## 2 answers

### Answer by username_3 on 2018-07-24. Score: 4 | Accepted answer

Far from "orbit" some of the longest telescopes in history are:

* Tubed: "[Hevelius' Longest Telescope from Machinae Coelestis](https://en.wikipedia.org/wiki/Aerial_telescope#Very_long_%22tubed%22_telescopes)" - 150 feet

[![Hevelius' Telescope](https://i.sstatic.net/yxAOP.jpg)](https://i.sstatic.net/yxAOP.jpg)

* Tubeless: "[Huygen's Telescope](https://en.wikipedia.org/wiki/Aerial_telescope)" - 210 feet

[![Huygen's Telescope](https://i.sstatic.net/W1BT9.jpg)](https://i.sstatic.net/W1BT9.jpg)

Apparently [Adrian Auzout](https://en.m.wikipedia.org/wiki/Adrien_Auzout) and others made telescopes of from [300 to 600 ft](https://en.wikipedia.org/wiki/Aerial_telescope#Tubeless_%22aerial%22_telescopes) (90 to 180 m) focal length, but I've not found a drawing from the late 1600's of it.

In theory you could have a distant *objective lens* but either it would need to be huge (costly) or your field of view would need to be extremely narrow (only useful for extremely distant objects). Then there's the cost of stabilizing the lens and maintaining alignment.


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### Answer by username_4 on 2018-07-23. Score: 6

Speaking in general, telescopes are designed as complete systems from the beginning. It's not generally feasible to improve performance by just adding yet another lens or mirror to the assembly. The reasons for this are not simple to explain, since this is basically the whole theory of instrument design.

Usually you start with a set of requirements (limiting magnitude, angular resolution, linear resolution in prime focus, etc) and with a set of constraints (cost, size, weight, materials).

You settle on a given architecture (newtonian reflector, Ritchey-Chrétien, doublet / triplet / quadruplet refractor, etc), and then start to work out the main parameters: aperture, focal length, etc.

There's an iterative process involving computer aided design to work out the details of each optical element; at each step you need to solve problems such as eliminating internal reflections, etc.

In the end, what you have is the design of the whole optical stack: say a Dall-Kirkham reflector, 1 meter aperture, f/8, with mirrors of whatever radiuses of curvature, etc.

Once that's set in stone, it's hard to change in a major way. Minor upgrades might be possible (add a corrector lens, or a different secondary mirror), but not huge modifications.

---

TLDR: No. Start with a bigger instrument from scratch if that's what you want.


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