<p>This kind of location is called a <a href="https://en.wikipedia.org/wiki/Peak_of_eternal_light" rel="noreferrer">peak of eternal light</a>.</p>

<p>Apparently there is <a href="http://www.skyandtelescope.com/observing/peaks-of-eternal-light/" rel="noreferrer">no certain identification</a> of such a peak on the Moon, but there are definitely places that get more than 86% sunlight during the lunar year (ignoring eclipses). <a href="https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2008GL035692" rel="noreferrer">Kaguya did not find any permanent peaks</a>, but there is apeak near Peary at the North Pole that gets 89%, and <a href="https://linkinghub.elsevier.com/retrieve/pii/S0019103510001375" rel="noreferrer">several places near the South Pole that have multi-month illumination</a>. </p>

<p>Calculating the requirements for such a peak is complicated since the moon is definitely not spherical on the hundreds of meter scale; at the very least one needs an ellipsoid model. The south pole situation is complicated because <a href="http://www.thespacereview.com/article/2423/1" rel="noreferrer">there is a large basin around the actual pole</a>.</p>

CC BY-SA 4.0
2023-11-12T18:57:38.127Z
Just fyi, answer(s) to [Shape and dimensions of the Moon's reference surface for selenographic latitude/longitude?](https://space.stackexchange.com/q/27359/12102) indicate that an ellipsoid would be of no use - while higher order terms would be giant, this term would be very, very small.
uhoh
CC BY-SA 3.0
2018-04-30T07:19:15.200Z
2018-04-30T07:19:15.200Z
Anders Sandberg
<p>Is there a place on Moon (sure it's near north or south pole) that is always lit by sun? It's to install solar panels if I will choose to make rancho there :)</p>

<p>What diameter of Moon Polar circle?
How high the hill or mast on the pole should be to be always lit?</p>

<p>I used some online calculators and found next:</p>

<blockquote>
  <p>Axial tilt to ecliptic is <strong>1.5424°</strong>, Lunar Radius <strong>1738km</strong></p>
  
  <p>Polar circle is <strong>46.8km</strong></p>
  
  <p>Spherical cap height <strong>0.15km</strong></p>
</blockquote>

<p>Are my calculations correct? It shows that it should be near <strong>150 meters high</strong>. Is any high enough hill exists on a poles? </p>

<p>P.S. Where I can check good 3d model of Moon with elevation (sure there is no sea level but ideal sphere)?</p>

<p>Thanks</p>

CC BY-SA 3.0
2018-04-30T17:42:44.763Z
One nit: clearly nowhere on the moon can receive light from the sun during a lunar eclipse.
Carl Witthoft
CC BY-SA 3.0
2018-05-01T08:36:24.207Z
@CarlWitthoft Not so clearly: even when the Moon is fully within the umbra of a total lunar eclipse, it still receives some sunlight refracted through Earth’s atmosphere. Hence the “blood moon”.
Chappo Hasn't Forgotten
CC BY-SA 3.0
2018-05-01T11:45:59.983Z
@Chappo  well, yeah,  and then I could point out that the moon receives a couple hundred photons/second of sunlight reflected back off Mars :-)
Carl Witthoft
CC BY-SA 4.0
2018-05-02T02:49:54.877Z
@CarlWitthoft agreed, and we can also see the new moon dimly due to reflection of galactic light (and probably some re-reflected sunlight from Earth). But my point is that if you're going to nit-pick with the emphasis on your correction being *clearly* obvious, accuracy becomes important. While the Moon appears much dimmer during a lunar eclipse, the amount of direct (penumbra) and refracted (umbra) sunlight it receives is still substantial, and *orders of magnitude* more than any reflected sunlight from Mars.
Chappo Hasn't Forgotten
CC BY-SA 4.0
2023-11-11T01:20:05.703Z
Mare Vaporum sounds pretty lit.
Acccumulation
<the-moon>
Place on Moon that always lit?
HardQuestions
# Place on Moon that always lit?

(Asked by: username_0 on 2018-04-29)

Is there a place on Moon (sure it's near north or south pole) that is always lit by sun? It's to install solar panels if I will choose to make rancho there :)

What diameter of Moon Polar circle?
How high the hill or mast on the pole should be to be always lit?

I used some online calculators and found next:

> Axial tilt to ecliptic is **1.5424°**, Lunar Radius **1738km**
>
> Polar circle is **46.8km**
>
> Spherical cap height **0.15km**

Are my calculations correct? It shows that it should be near **150 meters high**. Is any high enough hill exists on a poles?

P.S. Where I can check good 3d model of Moon with elevation (sure there is no sea level but ideal sphere)?

Thanks

**Tags:** the-moon
> **Comments:**
> **username_1**: One nit: clearly nowhere on the moon can receive light from the sun during a lunar eclipse.  
> **username_2**: @CarlWitthoft Not so clearly: even when the Moon is fully within the umbra of a total lunar eclipse, it still receives some sunlight refracted through Earth’s atmosphere. Hence the “blood moon”.  
> **username_1**: @Chappo  well, yeah,  and then I could point out that the moon receives a couple hundred photons/second of sunlight reflected back off Mars :-)  
> **username_2**: @CarlWitthoft agreed, and we can also see the new moon dimly due to reflection of galactic light (and probably some re-reflected sunlight from Earth). But my point is that if you're going to nit-pick with the emphasis on your correction being *clearly* obvious, accuracy becomes important. While the Moon appears much dimmer during a lunar eclipse, the amount of direct (penumbra) and refracted (umbra) sunlight it receives is still substantial, and *orders of magnitude* more than any reflected sunlight from Mars.  
> **username_3**: Mare Vaporum sounds pretty lit.  

---

## 1 answers

### Answer by username_4 on 2018-04-30. Score: 9 | Accepted answer

This kind of location is called a [peak of eternal light](https://en.wikipedia.org/wiki/Peak_of_eternal_light).

Apparently there is [no certain identification](http://www.skyandtelescope.com/observing/peaks-of-eternal-light/) of such a peak on the Moon, but there are definitely places that get more than 86% sunlight during the lunar year (ignoring eclipses). [Kaguya did not find any permanent peaks](https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2008GL035692), but there is apeak near Peary at the North Pole that gets 89%, and [several places near the South Pole that have multi-month illumination](https://linkinghub.elsevier.com/retrieve/pii/S0019103510001375).

Calculating the requirements for such a peak is complicated since the moon is definitely not spherical on the hundreds of meter scale; at the very least one needs an ellipsoid model. The south pole situation is complicated because [there is a large basin around the actual pole](http://www.thespacereview.com/article/2423/1).

> **Comments:**
> **username_5**: Just fyi, answer(s) to [Shape and dimensions of the Moon's reference surface for selenographic latitude/longitude?](https://space.stackexchange.com/q/27359/12102) indicate that an ellipsoid would be of no use - while higher order terms would be giant, this term would be very, very small.  

---

