<p>It's a <a href="https://en.wikipedia.org/wiki/Campbell%E2%80%93Stokes_recorder">Campbell-Stokes sunshine recorder</a>, used to record the times at which the sun is shining. It acts as a lens, focusing the sunlight onto a piece of card. If the sun is shining, the focused beam will burn a hole through the card at that point.</p>

<p>Here's a closer view of a sunshine recorder in Wendelstein, Bavaria:
<img src="https://upload.wikimedia.org/wikipedia/commons/thumb/4/43/Heliograph_wendelstein_2002_00a.jpg/640px-Heliograph_wendelstein_2002_00a.jpg" alt="Sunshine recorder">
<sup>Source: <a href="https://commons.wikimedia.org/wiki/File:Heliograph_wendelstein_2002_00a.jpg">Wikimedia Commons</a></sup></p>

<p>And here's a used recording card with holes burned through it:
<img src="https://upload.wikimedia.org/wikipedia/commons/thumb/6/65/Sunshine_card_closeup.JPG/636px-Sunshine_card_closeup.JPG" alt="Recording card">
<sup>Source: <a href="https://commons.wikimedia.org/wiki/File:Sunshine_card_closeup.JPG">Wikimedia Commons</a></sup></p>

CC BY-SA 3.0
2017-01-11T09:03:46.810Z
But beware of early morning frost on the glass sphere, which may diffuse the focus so that early sunshine is not recorded.
Gordon Stanger
CC BY-SA 3.0
2017-01-08T10:22:09.260Z
2017-01-08T10:34:04.937Z
2017-01-08T10:34:04.937Z
Pont
<p>I found what looks like a "crystal ball" in a meteorological station in the Vlădeasa mountains (Romania). What is its purpose? </p>

<p><a href="https://i.sstatic.net/Ur2Ww.jpg" rel="noreferrer"><img src="https://i.sstatic.net/Ur2Ww.jpg" alt="enter image description here"></a></p>

CC BY-SA 3.0
2017-01-08T20:36:20.147Z
It's a high-tech version of the [weather rock](https://en.wikipedia.org/wiki/Weather_rock)
Mark
<meteorology><weather-forecasting><instrumentation>
What is this "crystal ball" located at a meteorological station?
andi
# What is this "crystal ball" located at a meteorological station?

(Asked by: username_0 on 2017-01-08)

I found what looks like a "crystal ball" in a meteorological station in the Vlădeasa mountains (Romania). What is its purpose?

[![enter image description here](https://i.sstatic.net/Ur2Ww.jpg)](https://i.sstatic.net/Ur2Ww.jpg)

**Tags:** meteorology, weather-forecasting, instrumentation

> **Comments:**
> **username_1**: It's a high-tech version of the [weather rock](https://en.wikipedia.org/wiki/Weather_rock)  

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## 1 answers

### Answer by username_2 on 2017-01-08. Score: 33 | Accepted answer

It's a [Campbell-Stokes sunshine recorder](https://en.wikipedia.org/wiki/Campbell%E2%80%93Stokes_recorder), used to record the times at which the sun is shining. It acts as a lens, focusing the sunlight onto a piece of card. If the sun is shining, the focused beam will burn a hole through the card at that point.

Here's a closer view of a sunshine recorder in Wendelstein, Bavaria:
![Sunshine recorder](https://upload.wikimedia.org/wikipedia/commons/thumb/4/43/Heliograph_wendelstein_2002_00a.jpg/640px-Heliograph_wendelstein_2002_00a.jpg)
Source: [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Heliograph_wendelstein_2002_00a.jpg)

And here's a used recording card with holes burned through it:
![Recording card](https://upload.wikimedia.org/wikipedia/commons/thumb/6/65/Sunshine_card_closeup.JPG/636px-Sunshine_card_closeup.JPG)
Source: [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Sunshine_card_closeup.JPG)

> **Comments:**
> **username_3**: But beware of early morning frost on the glass sphere, which may diffuse the focus so that early sunshine is not recorded.  

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