<p>To simplify, I used Starry Night to generate a visualization.</p>
<p><a href="https://i.sstatic.net/T8v1v.jpg" rel="noreferrer"><img src="https://i.sstatic.net/T8v1v.jpg" alt="enter image description here" /></a></p>
<p>The yellow arc is a piece of the ecliptic.  You can see (in faint gray) the center of the yellow arc is labeled 'Dec'.  The Sun will be in this part of the sky in December.</p>
<p>You can also see planets of the inner solar system and in the background, part of Sagittarius (and the Teapot asterism) is labeled.   Apologies for using Sgr A East instead of Sgr A* ... (basically the same spot at this scale).</p>
<p>So the answer to your question is, if we assume you are standing on the Earth and have to contend with an atmosphere, then yes ... you can only view the area near the center of the galaxy for part of the year.  If you didn't have to deal with an atmosphere then (e.g. if you were floating in space) then you could see it all the time -- you wouldn't have to deal with the bright blue sky blocking out your view to all the stars in that part of the sky.</p>
<p>The solar system's plane isn't perfectly edge-on to the center of the galaxy ... it is is slightly south of the ecliptic plane.  And... you can certainly see it more than just &quot;half&quot; of the year.  As long as it is dark and clear and the Sun isn't too close to that part of the ecliptic than you can see.  There's little hope of that in the month of December and even November or January might be a little tough.  But certainly February through October it is visible at <em>some</em> time during the night.</p>
<p>For example, in February you would see it in the pre-dawn hours.  In October you would see it in the early evening after sunset.  But that part of the sky <em>is</em> visible for easily 3/4 of the year.</p>
<p>There are exceptions.  If you're at the North Pole... you <em>never</em> see it at <em>any</em> time of the year.  At the South Pole it is a circumpolar object which never sets.  But the Sun is up for roughly half the year and down for the other half so you can only see it during the dark half of the year.</p>

CC BY-SA 4.0
2020-07-15T20:22:45.840Z
I never realized Van Gogh went into that level of detail in [Starry Night](https://en.wikipedia.org/wiki/The_Starry_Night) ;D
Davy M
CC BY-SA 4.0
2020-07-15T18:55:59.693Z
2020-07-15T18:55:59.693Z
Tim Campbell
<p>No, although there are times when it can't be seen, it isn't true that it is visible for 183 days of the year.</p>
<p>The general question could be &quot;If I take an arbitrary location on the sky (say a randomly chosen star) will it be visible for half the year?  The answer is &quot;it depends on the star!&quot; Polaris and many other stars are circumpolar for Northern hemisphere observers and are visible every night,  contrariwise, Polaris is never visible for Southern Hemisphere observers.</p>
<p>Now, the galactic centre happens to be located in Sagittarius, so co-incidentally is quite close to the plane of the solar system.  This means that for about two months of the year, the sun is too close to make observations easy, certainly in visible light from the Earth's surface.  At other times it will be visible, perhaps briefly.  Sagittarius and the galactic centre are also quite a few degrees South of the equator, so it is more easily visible from the southern hemisphere.</p>
<p>At 50 degrees North, The galactic centre sets at twilight at the start of October and doesn't rise until dawn at the middle of February,  between February and October (about 7½ months) the galactic centre is above the horizon at some point during the night. (The exact number of days depends on your definition of &quot;dawn&quot; and &quot;above the horizon&quot;) More southerly observers will see the galactic centre for longer. 50 degrees South, the galactic centre is above the horizon at some time during the night between January and November.  In Antarctica, the galactic centre is circumpolar, and so is above the horizon every night. But as the summer sun in Antarctica doesn't set, there are days when you can't &quot;see&quot; it. The optimum location would be 30 degrees South (or in space)</p>

CC BY-SA 4.0
2020-07-15T18:46:06.990Z
Yes of course! +1
planetmaker
CC BY-SA 4.0
2020-07-15T19:45:12.463Z
Note also that even if the galactic centre was in the plane of the ecliptic, like the questioner expected, "some point during the night" is an important qualification. An object doesn't necessarily need to be as much as 90 degrees away from the Sun in order to be visible in the night sky for some period of time after the Sun sets or before the Sun rises. Venus, for example, would never be "in the night sky" according to the questioner's diagram, since it's always on the Sun's side of any line you draw through the Earth perpendicular to the Sun-Earth axis.
Steve Jessop
CC BY-SA 4.0
2020-07-15T19:54:09.750Z
Basically what the questioner expects to be "in the night sky" is really, "above the horizon, at a latitude in the tropics that you choose to match the time of year, *at midnight*": that is to say in the half of the ecliptic that's on the non-Sunny side of that perpendicular line. But it can be plenty dark at times other than midnight, to see objects that set before midnight or rise after midnight!
Steve Jessop
CC BY-SA 4.0
2020-07-15T20:12:57.800Z
Sagittarius has two T and one G, not the other way around.
hobbs
CC BY-SA 4.0
2020-07-15T20:35:44.203Z
@JamesK: I think you might have to fix that yourself. Stackexchange deems correct spelling to be insufficiently important to allow anyone other than the author to make such a small change to an answer.
Steve Jessop
CC BY-SA 4.0
2020-07-15T20:38:15.467Z
Ah, actually, anyone with 2k rep on this site can do it: https://meta.stackexchange.com/questions/81520/how-to-overcome-edits-must-be-at-least-6-characters So, not hobbs. Because his edits (or mine) need to be approved, and correct spelling is deemed insufficiently important to spend a reviewer's time on.
Steve Jessop
CC BY-SA 4.0
2020-07-15T21:14:26.163Z
@JamesK Hobbs is unable to make that small of an edit as they are below the 1000 reputation limit.
Tim
CC BY-SA 4.0
2020-07-16T05:50:35.237Z
"At 50 degrees North,.." does the same holds true for "At 50 degrees South," with 6 months shift in time?
jimjim
CC BY-SA 4.0
2020-07-16T07:20:20.230Z
No,  you'll be able to see it for longer in the south. And there is no shift in time.  It is not visible because of the relative position of the sun, which is the same in both hemispheres.
James K
CC BY-SA 4.0
2020-07-15T14:50:05.743Z
2020-07-16T07:19:46.077Z
2020-07-16T07:19:46.077Z
James K
<p>I'm not an astronomer, please excuse my non-formal language.</p>
<p>Since we are located in one of the arms of the Milky way, the center of the galaxy should be in one direction from our location, while in the other direction, we stare into the &quot;other side&quot;.</p>
<p>So at nights as we are in the orbit area that is between the sun and the center of the galaxy we are able to see the center (the &quot;milky-way&quot;), while when in the other side of the orbit, at nights, we are not able to see it.</p>
<p>Does this mean we only see the <a href="https://upload.wikimedia.org/wikipedia/commons/thumb/4/43/ESO-VLT-Laser-phot-33a-07.jpg/1200px-ESO-VLT-Laser-phot-33a-07.jpg" rel="noreferrer">milky way</a> (meaning the milky-way's famous pattern) half of the year?</p>
<p>In the below diagram, the small circle is our year-orbit around our sun. Red dot is the earth location on day 0 of the year and the green dot is the earth location on day 180th of the year.</p>
<p>I know that as we are orbiting our sun, it also orbits the galaxy, but since it is so slow, it is negligible for this questions.</p>
<p><a href="https://i.sstatic.net/uUlSL.png" rel="noreferrer"><img src="https://i.sstatic.net/uUlSL.png" alt="diagram" /></a></p>
<p>Is this reasonable?</p>
<p>I mean, if we look at the sky, we will see the center of the galaxy only during half of the year?</p>

CC BY-SA 4.0
2020-07-15T10:45:25.057Z
Don't forget that the ecliptic plane and the galactic plane are **not** identical, they are not even parallel, the galactic plane is tilted at an angle of 60 degrees to the ecliptic. The answers to this question, [In which direction does the ecliptic plane make an angle of 60 degrees with galactic plane?](https://astronomy.stackexchange.com/questions/28071/), will help you understand where the center of our Galaxy is situated.
Yellow Sky
CC BY-SA 4.0
2020-07-15T14:08:04.663Z
related and unanswered: [How far have stars been seen beyond the center of the Milky Way?](https://astronomy.stackexchange.com/q/32794/7982), also see [Why the blank wedges in this very early 21 cm map of the Milky Way? (Oort et al. 1958)](https://astronomy.stackexchange.com/q/28083/7982) and [Where is the center of the Milky Way located?](https://astronomy.stackexchange.com/q/27964/7982) and [What is it exactly about these flares of infrared light from Sgr A* that “confirms” it is a supermassive black hole?](https://astronomy.stackexchange.com/q/28240/7982)
uhoh
CC BY-SA 4.0
2020-07-15T14:13:24.793Z
and [What spectral feature was used to confirm that S0-2 is “single and available”? What is Brγ?](https://astronomy.stackexchange.com/q/25261/7982) and [How did they estimate the mass of Sgr A*'s companion G2 without knowing what it was?](https://astronomy.stackexchange.com/q/33012/7982) and [How feasible is it that we could see the Central Black Hole Sgr A* occlude one of it's closely orbiting stars?](https://astronomy.stackexchange.com/q/32604/7982) and [How did they measure the distance to the center of our galaxy to 0.3% accuracy?](https://astronomy.stackexchange.com/q/32793/7982)
uhoh
CC BY-SA 4.0
2020-07-15T14:13:37.843Z
and [Why does the closest approach of star S2 to Sgr A* not appear to be near the focus of its elliptical orbit?](https://astronomy.stackexchange.com/a/35845/7982)
uhoh
<solar-system><milky-way>
Is it true that we see the center of the milky-way for only half of the year?
riorio
# Is it true that we see the center of the milky-way for only half of the year?

(Asked by: username_0 on 2020-07-15)

I'm not an astronomer, please excuse my non-formal language.

Since we are located in one of the arms of the Milky way, the center of the galaxy should be in one direction from our location, while in the other direction, we stare into the "other side".

So at nights as we are in the orbit area that is between the sun and the center of the galaxy we are able to see the center (the "milky-way"), while when in the other side of the orbit, at nights, we are not able to see it.

Does this mean we only see the [milky way](https://upload.wikimedia.org/wikipedia/commons/thumb/4/43/ESO-VLT-Laser-phot-33a-07.jpg/1200px-ESO-VLT-Laser-phot-33a-07.jpg) (meaning the milky-way's famous pattern) half of the year?

In the below diagram, the small circle is our year-orbit around our sun. Red dot is the earth location on day 0 of the year and the green dot is the earth location on day 180th of the year.

I know that as we are orbiting our sun, it also orbits the galaxy, but since it is so slow, it is negligible for this questions.

[![diagram](https://i.sstatic.net/uUlSL.png)](https://i.sstatic.net/uUlSL.png)

Is this reasonable?

I mean, if we look at the sky, we will see the center of the galaxy only during half of the year?

**Tags:** solar-system, milky-way
> **Comments:**
> **username_1**: Don't forget that the ecliptic plane and the galactic plane are **not** identical, they are not even parallel, the galactic plane is tilted at an angle of 60 degrees to the ecliptic. The answers to this question, [In which direction does the ecliptic plane make an angle of 60 degrees with galactic plane?](https://astronomy.stackexchange.com/questions/28071/), will help you understand where the center of our Galaxy is situated.  
> **username_2**: related and unanswered: [How far have stars been seen beyond the center of the Milky Way?](https://astronomy.stackexchange.com/q/32794/7982), also see [Why the blank wedges in this very early 21 cm map of the Milky Way? (Oort et al. 1958)](https://astronomy.stackexchange.com/q/28083/7982) and [Where is the center of the Milky Way located?](https://astronomy.stackexchange.com/q/27964/7982) and [What is it exactly about these flares of infrared light from Sgr A* that “confirms” it is a supermassive black hole?](https://astronomy.stackexchange.com/q/28240/7982)  
> **username_2**: and [What spectral feature was used to confirm that S0-2 is “single and available”? What is Brγ?](https://astronomy.stackexchange.com/q/25261/7982) and [How did they estimate the mass of Sgr A*'s companion G2 without knowing what it was?](https://astronomy.stackexchange.com/q/33012/7982) and [How feasible is it that we could see the Central Black Hole Sgr A* occlude one of it's closely orbiting stars?](https://astronomy.stackexchange.com/q/32604/7982) and [How did they measure the distance to the center of our galaxy to 0.3% accuracy?](https://astronomy.stackexchange.com/q/32793/7982)  
> **username_2**: and [Why does the closest approach of star S2 to Sgr A* not appear to be near the focus of its elliptical orbit?](https://astronomy.stackexchange.com/a/35845/7982)  

---

## 2 answers

### Answer by username_5 on 2020-07-15. Score: 18 | Accepted answer

No, although there are times when it can't be seen, it isn't true that it is visible for 183 days of the year.

The general question could be "If I take an arbitrary location on the sky (say a randomly chosen star) will it be visible for half the year? The answer is "it depends on the star!" Polaris and many other stars are circumpolar for Northern hemisphere observers and are visible every night, contrariwise, Polaris is never visible for Southern Hemisphere observers.

Now, the galactic centre happens to be located in Sagittarius, so co-incidentally is quite close to the plane of the solar system. This means that for about two months of the year, the sun is too close to make observations easy, certainly in visible light from the Earth's surface. At other times it will be visible, perhaps briefly. Sagittarius and the galactic centre are also quite a few degrees South of the equator, so it is more easily visible from the southern hemisphere.

At 50 degrees North, The galactic centre sets at twilight at the start of October and doesn't rise until dawn at the middle of February, between February and October (about 7½ months) the galactic centre is above the horizon at some point during the night. (The exact number of days depends on your definition of "dawn" and "above the horizon") More southerly observers will see the galactic centre for longer. 50 degrees South, the galactic centre is above the horizon at some time during the night between January and November. In Antarctica, the galactic centre is circumpolar, and so is above the horizon every night. But as the summer sun in Antarctica doesn't set, there are days when you can't "see" it. The optimum location would be 30 degrees South (or in space)

> **Comments:**
> **username_6**: Yes of course! +1  
> **username_7**: Note also that even if the galactic centre was in the plane of the ecliptic, like the questioner expected, "some point during the night" is an important qualification. An object doesn't necessarily need to be as much as 90 degrees away from the Sun in order to be visible in the night sky for some period of time after the Sun sets or before the Sun rises. Venus, for example, would never be "in the night sky" according to the questioner's diagram, since it's always on the Sun's side of any line you draw through the Earth perpendicular to the Sun-Earth axis.  
> **username_7**: Basically what the questioner expects to be "in the night sky" is really, "above the horizon, at a latitude in the tropics that you choose to match the time of year, *at midnight*": that is to say in the half of the ecliptic that's on the non-Sunny side of that perpendicular line. But it can be plenty dark at times other than midnight, to see objects that set before midnight or rise after midnight!  
> **username_8**: Sagittarius has two T and one G, not the other way around.  
> **username_7**: @JamesK: I think you might have to fix that yourself. Stackexchange deems correct spelling to be insufficiently important to allow anyone other than the author to make such a small change to an answer.  
> **username_7**: Ah, actually, anyone with 2k rep on this site can do it: https://meta.stackexchange.com/questions/81520/how-to-overcome-edits-must-be-at-least-6-characters So, not hobbs. Because his edits (or mine) need to be approved, and correct spelling is deemed insufficiently important to spend a reviewer's time on.  
> **username_9**: @JamesK Hobbs is unable to make that small of an edit as they are below the 1000 reputation limit.  
> **username_10**: "At 50 degrees North,.." does the same holds true for "At 50 degrees South," with 6 months shift in time?  
> **username_5**: No,  you'll be able to see it for longer in the south. And there is no shift in time.  It is not visible because of the relative position of the sun, which is the same in both hemispheres.  

---

### Answer by username_3 on 2020-07-15. Score: 6

To simplify, I used Starry Night to generate a visualization.

[![enter image description here](https://i.sstatic.net/T8v1v.jpg)](https://i.sstatic.net/T8v1v.jpg)

The yellow arc is a piece of the ecliptic. You can see (in faint gray) the center of the yellow arc is labeled 'Dec'. The Sun will be in this part of the sky in December.

You can also see planets of the inner solar system and in the background, part of Sagittarius (and the Teapot asterism) is labeled. Apologies for using Sgr A East instead of Sgr A\* ... (basically the same spot at this scale).

So the answer to your question is, if we assume you are standing on the Earth and have to contend with an atmosphere, then yes ... you can only view the area near the center of the galaxy for part of the year. If you didn't have to deal with an atmosphere then (e.g. if you were floating in space) then you could see it all the time -- you wouldn't have to deal with the bright blue sky blocking out your view to all the stars in that part of the sky.

The solar system's plane isn't perfectly edge-on to the center of the galaxy ... it is is slightly south of the ecliptic plane. And... you can certainly see it more than just "half" of the year. As long as it is dark and clear and the Sun isn't too close to that part of the ecliptic than you can see. There's little hope of that in the month of December and even November or January might be a little tough. But certainly February through October it is visible at *some* time during the night.

For example, in February you would see it in the pre-dawn hours. In October you would see it in the early evening after sunset. But that part of the sky *is* visible for easily 3/4 of the year.

There are exceptions. If you're at the North Pole... you *never* see it at *any* time of the year. At the South Pole it is a circumpolar object which never sets. But the Sun is up for roughly half the year and down for the other half so you can only see it during the dark half of the year.

> **Comments:**
> **username_4**: I never realized Van Gogh went into that level of detail in [Starry Night](https://en.wikipedia.org/wiki/The_Starry_Night) ;D  

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