<p>Well, for ultraviolet light they give (table I), <span class="math-container">$4.68-25.8 ~\text{ergs/s}\times 10^5$</span>, which would correspond to <span class="math-container">$80-260 ~\text{mW}$</span>. As about a visual light, seems Lunokhod-2 telemetry systems was measuring sky brigntness in <a href="https://ui.adsabs.harvard.edu/abs/1976LNP....48...41S/abstract" rel="nofollow noreferrer">S10</a> units,- relative light intensity to some &quot;standard candle&quot;,- light captured from a main sequence star per 1 square degree solid angle. In these units Earth typical night sky has about <span class="math-container">$220~S_{10}$</span> <a href="https://en.wikipedia.org/wiki/Sky_brightness" rel="nofollow noreferrer">brightness</a>. Lunokhod-2 claims giving brightness readings, even when within a shadow, of <span class="math-container">$4400~S_{10}$</span> units. That's about <span class="math-container">$20\times$</span> bigger brightness than at Earth night sky ! It may seem far too big value for a moon, but considering that moon has no light pollution, no atmosphere which would scatter Sun/stars light, and on average gray color of surface (which reflects light not bad, especially if you are in the highland calcium-rich region, which is brighter),- then it almost makes sense.</p>

CC BY-SA 4.0
2022-04-16T13:11:35.410Z
2022-04-16T13:16:36.453Z
2022-04-16T13:16:36.453Z
Agnius Vasiliauskas
<p>Looking at the report &quot;The Measurements of Sky Brightness on Lunokhod-2&quot;<sup><a href="https://www.researchgate.net/profile/Edward-Terez-2/publication/248081808_The_measurements_of_sky_brightness_on_Lunokhod-2/links/53f6c6a30cf22be01c451795/The-measurements-of-sky-brightness-on-Lunokhod-2.pdf?origin=publication_detail" rel="nofollow noreferrer">1</a></sup>, I read that the day time visible light sky brightness was so large that it was off the scale. Unfortunately I have no idea how to convert their units of measurement into units I am familiar with, lux or lumens.</p>
<p><strong>Reference</strong></p>
<ol>
<li>Severny, A. &amp; Terez, Edward &amp; Zvereva, A.. (<strong>1975</strong>). The measurements of sky brightness on Lunokhod-2. Earth Moon and Planets - EARTH MOON PLANET. 14. 123-128. 10.1007/BF00562978. (<a href="https://www.researchgate.net/profile/Edward-Terez-2/publication/248081808_The_measurements_of_sky_brightness_on_Lunokhod-2/links/53f6c6a30cf22be01c451795/The-measurements-of-sky-brightness-on-Lunokhod-2.pdf?origin=publication_detail" rel="nofollow noreferrer">pdf</a>)</li>
</ol>

CC BY-SA 4.0
2022-04-16T07:30:11.420Z
Please add the relevant information also to this posting instead of only linking the paper
planetmaker
CC BY-SA 4.0
2022-04-17T14:40:31.587Z
http://stjarnhimlen.se/comp/radfaq.html#7 may help, as may https://physics.stackexchange.com/questions/340230/
Barry Carter
CC BY-SA 4.0
2022-04-17T19:48:17.260Z
Thanks for the stjamhmlen link, very comprehensive.
Solon
<the-moon><light>
Lunar sky brightness
Solon
# Lunar sky brightness

(Asked by: username_0 on 2022-04-15)

Looking at the report "The Measurements of Sky Brightness on Lunokhod-2"[1](https://www.researchgate.net/profile/Edward-Terez-2/publication/248081808_The_measurements_of_sky_brightness_on_Lunokhod-2/links/53f6c6a30cf22be01c451795/The-measurements-of-sky-brightness-on-Lunokhod-2.pdf?origin=publication_detail), I read that the day time visible light sky brightness was so large that it was off the scale. Unfortunately I have no idea how to convert their units of measurement into units I am familiar with, lux or lumens.

**Reference**

1. Severny, A. & Terez, Edward & Zvereva, A.. (**1975**). The measurements of sky brightness on Lunokhod-2. Earth Moon and Planets - EARTH MOON PLANET. 14. 123-128. 10.1007/BF00562978. ([pdf](https://www.researchgate.net/profile/Edward-Terez-2/publication/248081808_The_measurements_of_sky_brightness_on_Lunokhod-2/links/53f6c6a30cf22be01c451795/The-measurements-of-sky-brightness-on-Lunokhod-2.pdf?origin=publication_detail))

**Tags:** the-moon, light

> **Comments:**
> **username_1**: Please add the relevant information also to this posting instead of only linking the paper  
> **username_2**: http://stjarnhimlen.se/comp/radfaq.html#7 may help, as may https://physics.stackexchange.com/questions/340230/  
> **username_0**: Thanks for the stjamhmlen link, very comprehensive.  

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## 1 answers

### Answer by username_3 on 2022-04-16. Score: 2

Well, for ultraviolet light they give (table I), $4.68-25.8 ~\text{ergs/s}\times 10^5$, which would correspond to $80-260 ~\text{mW}$. As about a visual light, seems Lunokhod-2 telemetry systems was measuring sky brigntness in [S10](https://ui.adsabs.harvard.edu/abs/1976LNP....48...41S/abstract) units,- relative light intensity to some "standard candle",- light captured from a main sequence star per 1 square degree solid angle. In these units Earth typical night sky has about $220~S\_{10}$ [brightness](https://en.wikipedia.org/wiki/Sky_brightness). Lunokhod-2 claims giving brightness readings, even when within a shadow, of $4400~S\_{10}$ units. That's about $20\times$ bigger brightness than at Earth night sky ! It may seem far too big value for a moon, but considering that moon has no light pollution, no atmosphere which would scatter Sun/stars light, and on average gray color of surface (which reflects light not bad, especially if you are in the highland calcium-rich region, which is brighter),- then it almost makes sense.


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