<p>If relevant; Comparing binocs 10x50mm vs. SkyMasters 25x70mm, the 70mm gives for example:</p>
<ul>
<li>Much more detail on the Orion Nebula</li>
<li>Andromeda slightly more detail of spiral shape vs. smudge</li>
<li>Myriad of detail in the Beehive Cluster (Messier 44 or Praesepe) in the Cancer Constellation</li>
</ul>
<p>..in addition to the ones you mentioned (Mountain tops on the Moon, clear bands on Jupiter and clear gap between rings and planet on Saturn).</p>
<p>And of course, you see hundreds/thousands of more stars at almost any random point in the Milky Way.</p>
<p>But it sort of stops there. Even if the difference is a bit like using a magnifying glass vs. transporting yourself into space.</p>

CC BY-SA 4.0
2024-02-28T20:37:54.857Z
Thanks. This is the first response that really addresses the question. As for the many more stars seen, that might be true, and even interesting, but they're still just more dots. Thanks again.
ispiro
CC BY-SA 4.0
2024-02-28T16:34:07.677Z
2024-02-28T16:37:52.043Z
2024-02-28T16:37:52.043Z
2x_espresso
<p>What an increase in aperture gives is an increase in light-gathering ability.</p>
<p>This results in an increase in brightness and image resolution.</p>
<p>The size of the image does increase as the size of the aperture increases, but that's not as important because image size is selected by the observer, by using eyepieces of different focal lengths.<br />
The important part of the aperture increase is to see more and in more detail.</p>
<p>All telescopes have their limits at which increasing magnification only increases the size of a blurred image. There are the physical limits of the telescope and the limits imposed by the Earth's atmosphere. Increasing the aperture helps increase the level of magnification supportable.</p>
<p>Here are a couple of bad photos which I snapped with my phone through the eyepiece on December 20th, 2020 - during the conjunction of Jupiter and Saturn.<br />
To the eye, the brightness was about that of the first image, and the detail visible was more than that of the second.</p>
<p><img src="https://i.sstatic.net/Pvrus.jpg" width="300" height="400"><img src="https://i.sstatic.net/wxCjC.jpg" width="300" height="400"><br />
(ƒ/1.8 1/14 4.04mm ISO1552 and ƒ/1.8 1/30 4.04mm ISO100)<br />
(right-click and open in new tab to see full-size)</p>
<p>Here's one of the Moon on the same evening:
<img src="https://i.sstatic.net/iUYUM.jpg" width="720" height="960">(ƒ/1.8 1/60 4.04mm ISO100)</p>
<p>The telescope is an <strong>80mm</strong> aperture refractor with a <strong>560mm</strong> focal length. I can't remember which eyepiece was in it, but it was probably a 5mm or thereabouts, resulting in a magnification of 112x.</p>

CC BY-SA 4.0
2024-02-27T19:19:52.283Z
I don't understand how this answers the question.
ispiro
CC BY-SA 4.0
2024-02-27T19:26:06.560Z
@ispiro how does it _not_ answer the question "Will there be a difference in what can be seen with a 50mm telescope and a 70 or even 80 mm one?" ?
Aaron F
CC BY-SA 4.0
2024-02-27T19:37:31.063Z
I still don't know if your answer is yes or no. If yes, please tell me which object. Thanks.
ispiro
CC BY-SA 4.0
2024-02-27T19:56:27.237Z
@ispiro the answer is: yes. the object is: all of them.
Aaron F
CC BY-SA 4.0
2024-02-27T20:02:31.367Z
@ispiro in what way is it obviously wrong? have you calculated the area of a 50mm- and a 70mm-diameter circle yet? what did you discover?
Aaron F
CC BY-SA 4.0
2024-02-27T20:13:57.003Z
@ispiro there is more to "see a difference" than just the aperture as many already pointed out.
planetmaker
CC BY-SA 4.0
2024-02-27T20:21:06.247Z
@planetmaker My question is not if there will be a difference between 70 and 50. Obviously there will be.
ispiro
CC BY-SA 4.0
2024-02-27T21:45:12.377Z
@ispiro "My question is not if there will be a difference between 70 and 50". Your question "Will there be a difference in what can be seen with a 50mm telescope and a 70 or even 80 mm one?" is _literally_ that ¯\\_(ツ)_/¯
Aaron F
CC BY-SA 4.0
2024-02-28T20:36:22.380Z
I've now edited my question, mainly the tl;dr. I thought the question was clear, apparently it wasn't.
ispiro
CC BY-SA 4.0
2024-02-27T17:43:35.510Z
2024-02-27T17:43:35.510Z
Aaron F
<p>Double stars are quite sensitive to aperture.  The resolving power of a 50mm scope is about 2.2&quot; and a 70mm would be about 1.5&quot;, where both stars are about the same magnitude, and assuming good optics and seeing.</p>
<p>Alpha pisces at about 1.7&quot; should be split with a 70mm but not a 50mm telescope.
A bit of searching will find other examples, but be careful with your sources as some double star separations can change significantly over relatively short periods.</p>

CC BY-SA 4.0
2024-02-29T10:28:25.827Z
2024-02-29T10:28:25.827Z
Dr Chuck
<h2>tl;dr Is there a celestial object which has details that can be seen clearly by a 70mm telescope, but no details at all seen by a 50mm telescope of the same make. E.g. &quot;Jupiter has details that can be seen clearly by a 70 which are its stripes, while no details can be seen clearly by a 50&quot;.</h2>
<p>I was wondering if what my search gathered is correct.</p>
<p>From what I've gathered from forums etc. it seems like despite different opinions (as in other things), if one is looking to see details that can't be seen with the naked eye, <strong>not including fuzzy shapes</strong>, there are exactly 3 things that can be seen with a cheap telescope clearly:</p>
<ol>
<li>More details on the moon.</li>
<li>Details on Jupiter.</li>
<li>Details and rings of Saturn.</li>
</ol>
<p>Nothing more nothing less. (And specifically, no Deep Space Objects at all.)</p>
<p>And the difference between a 50mm one or a 70mm one would only be the size it would look.</p>
<p>Remember we're not talking about seeing a fuzzy shape of nebulae as opposed to a dot in the sky, only things that would look <strong>clear</strong>, albeit small. And that some detail will be added by the telescope, so just seeing Jupiter's moons as dots as opposed to not seeing them at all, doesn't count. I'm also assuming whatever would be a &quot;logical&quot; magnification with simple eyepieces.</p>
<p><strong>Obviously more will be seen with a 70mm than a 50mm. I'm asking if there is an object which will have details seen clearly by a 70 and no details at all seen clearly by a 50. If you answer yes, please say which object. E.g. A 70 will be able to see clear stripes on Jupiter while a 50 will only see a blob.</strong></p>
<p>If you absolutely need a specific type of telescope, let's look at this one:</p>
<p>50mm - <a href="https://rads.stackoverflow.com/amzn/click/com/B0000UMLYI" rel="nofollow noreferrer" rel="nofollow noreferrer">https://www.amazon.com/gp/product/B0000UMLYI/</a></p>
<p>70mm - <a href="https://rads.stackoverflow.com/amzn/click/com/B003AM87PU" rel="nofollow noreferrer" rel="nofollow noreferrer">https://www.amazon.com/gp/product/B003AM87PU/</a></p>

CC BY-SA 4.0
2024-02-26T23:22:47.347Z
I'm not an expert when it comes to lenses, but you're probably going to need a lot more than 70mm if you want to clearly resolve the surface Jupiter's moons. With 70mm, you should be able to see them, but as points of light - though it sounds like you're looking for better quality than that. It should be sufficient enough to see decent detail on the moon and even make out Saturn's rings, but you would still be looking at a relatively entry-level telescope.
4NT4R3S
CC BY-SA 4.0
2024-02-26T23:46:56.663Z
All of those are still fairly small.  Best advice is to find a club near you and actually look through some scopes members have.
Greg Miller
CC BY-SA 4.0
2024-02-27T01:32:33.203Z
Double stars, phase of Venus, open star clusters
JohnHoltz
CC BY-SA 4.0
2024-02-27T16:35:16.433Z
you're mixing "cheap telescopes" and a question about aperture. A cheap 70mm will probably show less than an expensive 50mm. There are many factors to take into account: the objective lenses and their quality, the diagonal's quality, the eyepiece's quality, the viewer's eyes' quality. Also the sky quality at the observing location. Or maybe there's no viewer involved and you're using a camera? Then the quality of the sensor and the cooling of the camera, and the mount being used, all affect the result.
Aaron F
CC BY-SA 4.0
2024-02-27T16:37:27.737Z
Oh and now I see the telescopes you linked, have a look at this https://www.reddit.com/r/dontbuyapowerseeker/
Aaron F
CC BY-SA 4.0
2024-02-27T19:09:23.540Z
@4NT4R3S I take your answer to be "yes". Please correct me if I'm wrong.
ispiro
CC BY-SA 4.0
2024-02-27T19:14:49.670Z
@JohnHoltz `Double stars` - would still be looking at two points, `phase of Venus` - this might actually be interesting, but from what I've read, no 70mm scope will see this more than as a hazy view. If I'm wrong, please correct me., `open star clusters` - If a general shape of the cluster can be discerned (as opposed to just more point-stars) this might actually be interesting. But will those be scene with a 70mm one and ***not with a 50mm one***? Also, thanks!
ispiro
CC BY-SA 4.0
2024-02-27T19:19:07.317Z
@AaronF `A cheap 70mm will probably show less than an expensive 50mm` - Assuming telescopes of the same quality and only the size difference, are you saying the answer to the question in the title is yes? If so, what celestial object?
ispiro
CC BY-SA 4.0
2024-02-27T19:20:46.090Z
@ispiro, it's both yes and no. Yes, you can definitely see objects that cannot be/are difficult to make out with the naked eye such as the ones you listed with a 50-70mm, but it likely will not be of the most phenomenal quality. I suggest trying to search for images taken with your desired lens so you can be the judge of that though.
4NT4R3S
CC BY-SA 4.0
2024-02-27T19:20:58.497Z
@GregMiller Thanks. And about the question, do you think it's yes?
ispiro
CC BY-SA 4.0
2024-02-27T19:22:05.897Z
@4NT4R3S The question is between 70 and 50. Not vs the naked eye. Do you think for that it's yes?
ispiro
CC BY-SA 4.0
2024-02-27T19:25:40.590Z
@ispiro Yes, there should generally be a difference in magnification (and thus the details you will see since the image is "closer") between 50 and 70mm. Aaron made a good point about aperture and sky quality, so take more into consideration than just the length, since a poor image is still a poor image no matter how large it is.
4NT4R3S
CC BY-SA 4.0
2024-02-27T19:30:32.177Z
Calculate the area of a circle that's 50mm in diameter and compare it to the area of a circle that's 70mm in diameter. What's the difference?
Aaron F
CC BY-SA 4.0
2024-02-27T19:54:24.537Z
@4NT4R3S So can you point to a specific object that would have some clear detail with a 70 and not with a 50? Which one, Jupiter perhaps?
ispiro
CC BY-SA 4.0
2024-02-27T20:13:58.527Z
@ispiro, Yes, Jupiter is a good example, as well as ridges along the moon. A 70mm has a focal length 1.4x greater than 50mm for perspective. Again, it is always best to look at some images online if you can find them to compare lenses
4NT4R3S
CC BY-SA 4.0
2024-02-27T20:20:17.870Z
@4NT4R3S So a 50mm telescope won't be able to see ***any*** details clearly on Jupiter? Not even any stripes? And won't be able to see any more details on the moon than a naked eye? (Obviously more will be seen with a 70mm one, but of course, that's not the question.)
ispiro
CC BY-SA 4.0
2024-02-27T20:37:20.677Z
@ispiro, You'll probably see at least some colors with a 50mm, I'm just saying that more detail might be visible with a 70mm due to its amplification. I just came across a source regarding Saturn's rings: According to Celestron, a minimum of 50mm aperture with 25x zoom is sufficient for viewing Saturn's rings to give you an idea https://www.celestron.com/blogs/knowledgebase/the-ultimate-guide-to-observing-saturn
4NT4R3S
CC BY-SA 4.0
2024-02-27T21:18:11.940Z
@4NT4R3S Thanks.
ispiro
<telescope><amateur-observing>
Will there be a difference in what can be seen with a 50mm telescope and a 70 or even 80 mm one?
ispiro
# Will there be a difference in what can be seen with a 50mm telescope and a 70 or even 80 mm one?

(Asked by: username_0 on 2024-02-26)

## tl;dr Is there a celestial object which has details that can be seen clearly by a 70mm telescope, but no details at all seen by a 50mm telescope of the same make. E.g. "Jupiter has details that can be seen clearly by a 70 which are its stripes, while no details can be seen clearly by a 50".

I was wondering if what my search gathered is correct.

From what I've gathered from forums etc. it seems like despite different opinions (as in other things), if one is looking to see details that can't be seen with the naked eye, **not including fuzzy shapes**, there are exactly 3 things that can be seen with a cheap telescope clearly:

1. More details on the moon.
2. Details on Jupiter.
3. Details and rings of Saturn.

Nothing more nothing less. (And specifically, no Deep Space Objects at all.)

And the difference between a 50mm one or a 70mm one would only be the size it would look.

Remember we're not talking about seeing a fuzzy shape of nebulae as opposed to a dot in the sky, only things that would look **clear**, albeit small. And that some detail will be added by the telescope, so just seeing Jupiter's moons as dots as opposed to not seeing them at all, doesn't count. I'm also assuming whatever would be a "logical" magnification with simple eyepieces.

**Obviously more will be seen with a 70mm than a 50mm. I'm asking if there is an object which will have details seen clearly by a 70 and no details at all seen clearly by a 50. If you answer yes, please say which object. E.g. A 70 will be able to see clear stripes on Jupiter while a 50 will only see a blob.**

If you absolutely need a specific type of telescope, let's look at this one:

50mm - [https://www.amazon.com/gp/product/B0000UMLYI/](https://rads.stackoverflow.com/amzn/click/com/B0000UMLYI)

70mm - [https://www.amazon.com/gp/product/B003AM87PU/](https://rads.stackoverflow.com/amzn/click/com/B003AM87PU)

**Tags:** telescope, amateur-observing

> **Comments:**
> **username_1**: I'm not an expert when it comes to lenses, but you're probably going to need a lot more than 70mm if you want to clearly resolve the surface Jupiter's moons. With 70mm, you should be able to see them, but as points of light - though it sounds like you're looking for better quality than that. It should be sufficient enough to see decent detail on the moon and even make out Saturn's rings, but you would still be looking at a relatively entry-level telescope.  
> **username_2**: All of those are still fairly small.  Best advice is to find a club near you and actually look through some scopes members have.  
> **username_3**: Double stars, phase of Venus, open star clusters  
> **username_4**: you're mixing "cheap telescopes" and a question about aperture. A cheap 70mm will probably show less than an expensive 50mm. There are many factors to take into account: the objective lenses and their quality, the diagonal's quality, the eyepiece's quality, the viewer's eyes' quality. Also the sky quality at the observing location. Or maybe there's no viewer involved and you're using a camera? Then the quality of the sensor and the cooling of the camera, and the mount being used, all affect the result.  
> **username_4**: Oh and now I see the telescopes you linked, have a look at this https://www.reddit.com/r/dontbuyapowerseeker/  
> **username_0**: @username_1 I take your answer to be "yes". Please correct me if I'm wrong.  
> **username_0**: @username_3 `Double stars` - would still be looking at two points, `phase of Venus` - this might actually be interesting, but from what I've read, no 70mm scope will see this more than as a hazy view. If I'm wrong, please correct me., `open star clusters` - If a general shape of the cluster can be discerned (as opposed to just more point-stars) this might actually be interesting. But will those be scene with a 70mm one and ***not with a 50mm one***? Also, thanks!  
> **username_0**: @username_4 `A cheap 70mm will probably show less than an expensive 50mm` - Assuming telescopes of the same quality and only the size difference, are you saying the answer to the question in the title is yes? If so, what celestial object?  
> **username_1**: @username_0, it's both yes and no. Yes, you can definitely see objects that cannot be/are difficult to make out with the naked eye such as the ones you listed with a 50-70mm, but it likely will not be of the most phenomenal quality. I suggest trying to search for images taken with your desired lens so you can be the judge of that though.  
> **username_0**: @username_2 Thanks. And about the question, do you think it's yes?  
> **username_0**: @username_1 The question is between 70 and 50. Not vs the naked eye. Do you think for that it's yes?  
> **username_1**: @username_0 Yes, there should generally be a difference in magnification (and thus the details you will see since the image is "closer") between 50 and 70mm. username_4 made a good point about aperture and sky quality, so take more into consideration than just the length, since a poor image is still a poor image no matter how large it is.  
> **username_4**: Calculate the area of a circle that's 50mm in diameter and compare it to the area of a circle that's 70mm in diameter. What's the difference?  
> **username_0**: @username_1 So can you point to a specific object that would have some clear detail with a 70 and not with a 50? Which one, Jupiter perhaps?  
> **username_1**: @username_0, Yes, Jupiter is a good example, as well as ridges along the moon. A 70mm has a focal length 1.4x greater than 50mm for perspective. Again, it is always best to look at some images online if you can find them to compare lenses  
> **username_0**: @username_1 So a 50mm telescope won't be able to see ***any*** details clearly on Jupiter? Not even any stripes? And won't be able to see any more details on the moon than a naked eye? (Obviously more will be seen with a 70mm one, but of course, that's not the question.)  
> **username_1**: @username_0, You'll probably see at least some colors with a 50mm, I'm just saying that more detail might be visible with a 70mm due to its amplification. I just came across a source regarding Saturn's rings: According to Celestron, a minimum of 50mm aperture with 25x zoom is sufficient for viewing Saturn's rings to give you an idea https://www.celestron.com/blogs/knowledgebase/the-ultimate-guide-to-observing-saturn  
> **username_0**: @username_1 Thanks.  

---

## 3 answers

### Answer by username_5 on 2024-02-28. Score: 4

If relevant; Comparing binocs 10x50mm vs. SkyMasters 25x70mm, the 70mm gives for example:

* Much more detail on the Orion Nebula
* Andromeda slightly more detail of spiral shape vs. smudge
* Myriad of detail in the Beehive Cluster (Messier 44 or Praesepe) in the Cancer Constellation

..in addition to the ones you mentioned (Mountain tops on the Moon, clear bands on Jupiter and clear gap between rings and planet on Saturn).

And of course, you see hundreds/thousands of more stars at almost any random point in the Milky Way.

But it sort of stops there. Even if the difference is a bit like using a magnifying glass vs. transporting yourself into space.

> **Comments:**
> **username_0**: Thanks. This is the first response that really addresses the question. As for the many more stars seen, that might be true, and even interesting, but they're still just more dots. Thanks again.  

---

### Answer by username_4 on 2024-02-27. Score: 3

What an increase in aperture gives is an increase in light-gathering ability.

This results in an increase in brightness and image resolution.

The size of the image does increase as the size of the aperture increases, but that's not as important because image size is selected by the observer, by using eyepieces of different focal lengths.  
The important part of the aperture increase is to see more and in more detail.

All telescopes have their limits at which increasing magnification only increases the size of a blurred image. There are the physical limits of the telescope and the limits imposed by the Earth's atmosphere. Increasing the aperture helps increase the level of magnification supportable.

Here are a couple of bad photos which I snapped with my phone through the eyepiece on December 20th, 2020 - during the conjunction of Jupiter and Saturn.  
To the eye, the brightness was about that of the first image, and the detail visible was more than that of the second.

![](https://i.sstatic.net/Pvrus.jpg)![](https://i.sstatic.net/wxCjC.jpg)  
(ƒ/1.8 1/14 4.04mm ISO1552 and ƒ/1.8 1/30 4.04mm ISO100)  
(right-click and open in new tab to see full-size)

Here's one of the Moon on the same evening:
![](https://i.sstatic.net/iUYUM.jpg)(ƒ/1.8 1/60 4.04mm ISO100)

The telescope is an **80mm** aperture refractor with a **560mm** focal length. I can't remember which eyepiece was in it, but it was probably a 5mm or thereabouts, resulting in a magnification of 112x.

> **Comments:**
> **username_0**: I don't understand how this answers the question.  
> **username_4**: @username_0 how does it _not_ answer the question "Will there be a difference in what can be seen with a 50mm telescope and a 70 or even 80 mm one?" ?  
> **username_0**: I still don't know if your answer is yes or no. If yes, please tell me which object. Thanks.  
> **username_4**: @username_0 the answer is: yes. the object is: all of them.  
> **username_4**: @username_0 in what way is it obviously wrong? have you calculated the area of a 50mm- and a 70mm-diameter circle yet? what did you discover?  
> **username_6**: @username_0 there is more to "see a difference" than just the aperture as many already pointed out.  
> **username_0**: @username_6 My question is not if there will be a difference between 70 and 50. Obviously there will be.  
> **username_4**: @username_0 "My question is not if there will be a difference between 70 and 50". Your question "Will there be a difference in what can be seen with a 50mm telescope and a 70 or even 80 mm one?" is _literally_ that ¯\\_(ツ)_/¯  
> **username_0**: I've now edited my question, mainly the tl;dr. I thought the question was clear, apparently it wasn't.  

---

### Answer by username_7 on 2024-02-29. Score: 1

Double stars are quite sensitive to aperture. The resolving power of a 50mm scope is about 2.2" and a 70mm would be about 1.5", where both stars are about the same magnitude, and assuming good optics and seeing.

Alpha pisces at about 1.7" should be split with a 70mm but not a 50mm telescope.
A bit of searching will find other examples, but be careful with your sources as some double star separations can change significantly over relatively short periods.


---

