<blockquote>
<p>Would it be sufficient to get to a really dark site with the naked eye</p>
</blockquote>
<p>In my personal experience, I have seen Andromeda Galaxy as a quite bright dot, in a hill station 2133 meters (6998 feet) above sea level with almost no light pollution, although the town is said to have light pollution of Class 2 in Bortle Scale. But it is not possible to see the disk of the galaxy with an unaided eye, the light gathering capacity of eye is very limited, like @PM2Ring states, the &quot;Refresh rate&quot; of our eye is around 1/10 of a second. Typically in an excellent dark sky, A binoculars would help to see some details of the galaxy. Or else a camera with a good zoom lens or with an Amateur telescope for an exposure of just 1 minute - 5 minutes can fetch enough details of the galaxy. Here's how it would look like. (It may look slightly better than the image below)</p>
<p><a href="https://i.sstatic.net/YHfrH.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/YHfrH.png" alt="enter image description here" /></a></p>
<p>Suppose if you want to see Andromeda galaxy as something like this:</p>
<p><a href="https://i.sstatic.net/u4AQe.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/u4AQe.jpg" alt="" /></a></p>
<p>Image from <a href="https://www.space.com/31222-andromeda-galaxy-autumn-skywatching.html" rel="nofollow noreferrer">Space.com</a></p>
<p>Then a Series of long exposure images have to be stacked or Curve stretch by some editing.</p>

CC BY-SA 4.0
2022-05-20T08:10:14.167Z
Can you put an angular scale on the picture?
ProfRob
CC BY-SA 4.0
2022-05-20T10:53:14.863Z
@ProfRob You mean a scale to measure its apparent angular size in the picture ?
Kavin Ishwaran
CC BY-SA 4.0
2022-05-20T19:19:01.423Z
Without angular scales on the image and details of how the image was obtained, your pictures are meaningless. I suppose I could try and work it out from the foreground stars but I'm not going to.
ProfRob
CC BY-SA 4.0
2022-05-21T04:04:23.977Z
@ProfRob I have obtained some informarion and will soon add it in the picture
Kavin Ishwaran
CC BY-SA 4.0
2022-05-20T06:42:56.707Z
2022-07-07T08:00:40.937Z
2022-07-07T08:00:40.937Z
Kavin Ishwaran
<p>You'd need new eyes able to collect vastly more photons. Barring an alien eye transplant, a large telescope mirror with a low power objective lens gives a reasonable view of the Andromeda galaxy in real time, but it will always be &quot;smudgy&quot;. Alternatively, a long exposure with a 35 mm digital camera on a moonless night will also do the trick, collecting more photons over time. Alas, human eyes need help from technology!</p>

CC BY-SA 4.0
2022-05-19T17:54:15.210Z
As it’s currently written, your answer is unclear. Please [edit] to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers [in the help center](/help/how-to-answer).
Community
CC BY-SA 4.0
2022-05-19T17:49:02.673Z
2022-05-19T17:49:02.673Z
DouglasPhillips
<p>In <a href="https://astronomy.stackexchange.com/questions/49367/is-the-scaling-in-this-composite-photo-reasonably-correct">this question</a> an image is shown (repeated below) which gives an idea of the &quot;true&quot; angular extent of the Andromeda galaxy in our sky.</p>
<p>When I see Andromeda it is usually a bit of a smudge perhaps the size of the full moon, presumably because I cannot see much beyond the bright nucleus and bulge of the galaxy.</p>
<p>Being a stellar astronomer, I have never thought much about the practicalities of seeing <em>extended</em> objects in the night sky.</p>
<p>My question is: what kind of observing conditions would allow me to see Andromeda with an angular size of <span class="math-container">$\sim 5$</span> degrees? Would it be sufficient to get to a really dark site with the naked eye, or would I also need to be looking for it with binoculars or a telescope? Or is it something where you must take a picture and do some processing to eliminate the general sky background?</p>
<p>EDIT: To be clear, I don't want my question reading back to me - as in &quot;you can only see a smudge with the naked eye&quot;; what I want to know is the observational conditions/instrument I need to able to see a several degree diameter Andromeda galaxy; preferably with the evidence?</p>
<p><a href="https://i.sstatic.net/gMZb3.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/gMZb3.jpg" alt="Andromeda vs the Moon" /></a></p>

CC BY-SA 4.0
2022-05-18T18:12:33.147Z
I cannot help but wonder if the Milky Way overwhelms the viewability of Andromeda.
BradV
CC BY-SA 4.0
2022-05-18T18:23:43.553Z
Are you asking in terms of seeing just with the naked/ aided eye/ camera, or in other words without the aid of longer exposures?
Justin T
CC BY-SA 4.0
2022-05-18T18:54:25.193Z
@BradV Andromeda is more than 20 degrees out of the galactic plane, so no.
ProfRob
CC BY-SA 4.0
2022-05-18T23:25:33.390Z
different but related: [How bright is Andromeda's center, in magnitudes per square arcminute or something similar?](https://astronomy.stackexchange.com/q/27307/7982) See also [The Luminosity Profile and Structural Parameters of the Andromeda Galaxy](https://iopscience.iop.org/article/10.1088/0004-637X/739/1/20) and and [The extended disc and halo of the Andromeda galaxy observed with Spitzer-IRAC](https://academic.oup.com/mnras/article/459/2/1403/2595032) To (not quite) answer your question, [just wait 3.5 billion years](https://hubblesite.org/contents/media/images/2012/20/3031-Image.html) :-)
uhoh
CC BY-SA 4.0
2022-05-18T23:54:27.550Z
and some good ole' plate scans and contour plots can be seen in [Multi-color photographic surface photometry of the Andromeda galaxy](https://scholarlypublications.universiteitleiden.nl/access/item%3A2721147/view) (also [here](https://adsabs.harvard.edu/full/1987A%26AS...69..311W) and [here](https://www.researchgate.net/publication/234369733_Multi-color_photographic_surface_photometry_of_the_Andromeda_galaxy)) and [Spectroscopy of Sky Glow](https://nightskymetrics.com/spectroscopy-of-sky-glow/)
uhoh
CC BY-SA 4.0
2022-05-19T03:17:42.527Z
Unfortunately, the human eye's maximum exposure time is quite short. According to https://www.cfa.harvard.edu/webscope/activities/pdfs/eyeTelComp.pdf your eye can collect light for no more than about 1/15th of a second before sending an image to your brain. There are some details at https://biology.stackexchange.com/questions/43095/why-cant-we-see-in-low-light-if-staring-long-enough
PM 2Ring
CC BY-SA 4.0
2022-05-19T03:18:23.173Z
Also see https://doi.org/10.1016/S0042-6989(98)00262-4 which discusses the optimum strategy of spatial and temporal summation for nocturnal animals. Increasing the interval of integration increases the sensitivity but reduces the resolution.
PM 2Ring
CC BY-SA 4.0
2022-05-19T11:33:21.347Z
I can see Andromeda from a dark site with the naked eye, but I've never measured the apparent angular size when I've done so. I'll try and do so when I next have the opportunity
Aaron F
CC BY-SA 4.0
2022-05-20T19:09:33.673Z
The portion of Andromeda you can see with the naked eye is the bright center region.   You won't be able to see the extended disk.
Dan Hanson
CC BY-SA 4.0
2022-05-21T04:06:34.947Z
Is it possible to approximate the camera's focal length used to get the Moon photo? I know long lenses and dramatic foregrounds can really distort the apparent size of the Moon. My guess is that modest length (100mm) was used because most 50mmish images have a much smaller Moon. Or the image was cropped.
BradV
CC BY-SA 4.0
2022-10-12T01:53:02.547Z
@ProfRob after a period of 'stewing' or 'percolating' I now understand how silly my thoughts of the Milky Way overpowering the viewability of the Andromeda galaxy. My initial thoughts were based on my childlike thinking that typical (not MW core) starlight 'in the neighborhood' would cause the human eye to 'stop down' to prevent viewing of the entirety of Andromeda. Boy, do I continue to be ignorant!!  Now I an slightly less so. Thank you!
BradV
<observational-astronomy><galaxy><amateur-observing>
How could I see Andromeda as large as in this picture?
ProfRob
# How could I see Andromeda as large as in this picture?

(Asked by: username_0 on 2022-05-18)

In [this question](https://astronomy.stackexchange.com/questions/49367/is-the-scaling-in-this-composite-photo-reasonably-correct) an image is shown (repeated below) which gives an idea of the "true" angular extent of the Andromeda galaxy in our sky.

When I see Andromeda it is usually a bit of a smudge perhaps the size of the full moon, presumably because I cannot see much beyond the bright nucleus and bulge of the galaxy.

Being a stellar astronomer, I have never thought much about the practicalities of seeing *extended* objects in the night sky.

My question is: what kind of observing conditions would allow me to see Andromeda with an angular size of $\sim 5$ degrees? Would it be sufficient to get to a really dark site with the naked eye, or would I also need to be looking for it with binoculars or a telescope? Or is it something where you must take a picture and do some processing to eliminate the general sky background?

EDIT: To be clear, I don't want my question reading back to me - as in "you can only see a smudge with the naked eye"; what I want to know is the observational conditions/instrument I need to able to see a several degree diameter Andromeda galaxy; preferably with the evidence?

[![Andromeda vs the Moon](https://i.sstatic.net/gMZb3.jpg)](https://i.sstatic.net/gMZb3.jpg)

**Tags:** observational-astronomy, galaxy, amateur-observing
> **Comments:**
> **username_1**: I cannot help but wonder if the Milky Way overwhelms the viewability of Andromeda.  
> **username_2**: Are you asking in terms of seeing just with the naked/ aided eye/ camera, or in other words without the aid of longer exposures?  
> **username_0**: @BradV Andromeda is more than 20 degrees out of the galactic plane, so no.  
> **username_3**: different but related: [How bright is Andromeda's center, in magnitudes per square arcminute or something similar?](https://astronomy.stackexchange.com/q/27307/7982) See also [The Luminosity Profile and Structural Parameters of the Andromeda Galaxy](https://iopscience.iop.org/article/10.1088/0004-637X/739/1/20) and and [The extended disc and halo of the Andromeda galaxy observed with Spitzer-IRAC](https://academic.oup.com/mnras/article/459/2/1403/2595032) To (not quite) answer your question, [just wait 3.5 billion years](https://hubblesite.org/contents/media/images/2012/20/3031-Image.html) :-)  
> **username_3**: and some good ole' plate scans and contour plots can be seen in [Multi-color photographic surface photometry of the Andromeda galaxy](https://scholarlypublications.universiteitleiden.nl/access/item%3A2721147/view) (also [here](https://adsabs.harvard.edu/full/1987A%26AS...69..311W) and [here](https://www.researchgate.net/publication/234369733_Multi-color_photographic_surface_photometry_of_the_Andromeda_galaxy)) and [Spectroscopy of Sky Glow](https://nightskymetrics.com/spectroscopy-of-sky-glow/)  
> **username_4**: Unfortunately, the human eye's maximum exposure time is quite short. According to https://www.cfa.harvard.edu/webscope/activities/pdfs/eyeTelComp.pdf your eye can collect light for no more than about 1/15th of a second before sending an image to your brain. There are some details at https://biology.stackexchange.com/questions/43095/why-cant-we-see-in-low-light-if-staring-long-enough  
> **username_4**: Also see https://doi.org/10.1016/S0042-6989(98)00262-4 which discusses the optimum strategy of spatial and temporal summation for nocturnal animals. Increasing the interval of integration increases the sensitivity but reduces the resolution.  
> **username_5**: I can see Andromeda from a dark site with the naked eye, but I've never measured the apparent angular size when I've done so. I'll try and do so when I next have the opportunity  
> **username_6**: The portion of Andromeda you can see with the naked eye is the bright center region.   You won't be able to see the extended disk.  
> **username_1**: Is it possible to approximate the camera's focal length used to get the Moon photo? I know long lenses and dramatic foregrounds can really distort the apparent size of the Moon. My guess is that modest length (100mm) was used because most 50mmish images have a much smaller Moon. Or the image was cropped.  
> **username_1**: @ProfRob after a period of 'stewing' or 'percolating' I now understand how silly my thoughts of the Milky Way overpowering the viewability of the Andromeda galaxy. My initial thoughts were based on my childlike thinking that typical (not MW core) starlight 'in the neighborhood' would cause the human eye to 'stop down' to prevent viewing of the entirety of Andromeda. Boy, do I continue to be ignorant!!  Now I an slightly less so. Thank you!  

---

## 2 answers

### Answer by username_7 on 2022-05-20. Score: 4

> Would it be sufficient to get to a really dark site with the naked eye

In my personal experience, I have seen Andromeda Galaxy as a quite bright dot, in a hill station 2133 meters (6998 feet) above sea level with almost no light pollution, although the town is said to have light pollution of Class 2 in Bortle Scale. But it is not possible to see the disk of the galaxy with an unaided eye, the light gathering capacity of eye is very limited, like @PM2Ring states, the "Refresh rate" of our eye is around 1/10 of a second. Typically in an excellent dark sky, A binoculars would help to see some details of the galaxy. Or else a camera with a good zoom lens or with an Amateur telescope for an exposure of just 1 minute - 5 minutes can fetch enough details of the galaxy. Here's how it would look like. (It may look slightly better than the image below)

[![enter image description here](https://i.sstatic.net/YHfrH.png)](https://i.sstatic.net/YHfrH.png)

Suppose if you want to see Andromeda galaxy as something like this:

[![](https://i.sstatic.net/u4AQe.jpg)](https://i.sstatic.net/u4AQe.jpg)

Image from [Space.com](https://www.space.com/31222-andromeda-galaxy-autumn-skywatching.html)

Then a Series of long exposure images have to be stacked or Curve stretch by some editing.

> **Comments:**
> **username_0**: Can you put an angular scale on the picture?  
> **username_7**: @ProfRob You mean a scale to measure its apparent angular size in the picture ?  
> **username_0**: Without angular scales on the image and details of how the image was obtained, your pictures are meaningless. I suppose I could try and work it out from the foreground stars but I'm not going to.  
> **username_7**: @ProfRob I have obtained some informarion and will soon add it in the picture  

---

### Answer by username_8 on 2022-05-19. Score: 1

You'd need new eyes able to collect vastly more photons. Barring an alien eye transplant, a large telescope mirror with a low power objective lens gives a reasonable view of the Andromeda galaxy in real time, but it will always be "smudgy". Alternatively, a long exposure with a 35 mm digital camera on a moonless night will also do the trick, collecting more photons over time. Alas, human eyes need help from technology!

> **Comments:**
> **username_9**: As it’s currently written, your answer is unclear. Please [edit] to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers [in the help center](/help/how-to-answer).  

---

