<p>Upsilon Sco is a blue/white (B-V =-0.17) B2 IV star according to the <a href="http://simbad.cds.unistra.fr/simbad/sim-id?Ident=Upsilon%20Sco&amp;NbIdent=1&amp;Radius=2&amp;Radius.unit=arcmin&amp;submit=submit%20id" rel="nofollow noreferrer">SIMBAD</a> database entry.</p>
<p>As a slightly evolved B-type star it is unlikely to show any great variability and none has been recorded as far as I can see from a scan of the available references on the star. In fact it was included in a catalogue of the &quot;least variable stars&quot; by <a href="https://www.aanda.org/component/article?access=bibcode&amp;bibcode=&amp;bibcode=2001A%2526A...367..297AFUL" rel="nofollow noreferrer">Adelman (2001)</a>, based on long duration monitoring by the Hipparcos satellite.</p>
<p>It might appear red if observed very low through a dusty atmosphere.</p>

CC BY-SA 4.0
2022-10-22T17:39:14.047Z
2022-10-22T17:39:14.047Z
ProfRob
<p>I was looking at the constellation Scorpius the other day, and noticed that the last star in the tail (the telson's tip) -- known as Upsilon Scorpii, υ Scorpii, or Lesath -- seemed yet more red than the &quot;heart&quot; of the scorpion -- Antares or Alpha Scorpii. Was it that I was drunk, or some kind of sky pollution? (Actually, a friend confirmed it was red, and she seemed sober than me.) Or is it, indeed, red? I couldn't find any information on-line. I saw <a href="http://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/icas/fchpix" rel="nofollow noreferrer">this database</a>, but don't know how to find a star by its name, or if they have information about the color.</p>

CC BY-SA 3.0
2017-10-11T11:28:11.847Z
@RobJeffries The red color was confirmed by at least another person (see my edit). Is there any site like a on-line telescope?
Rodrigo
CC BY-SA 3.0
2017-10-11T11:31:20.087Z
Rodrigo, what you saw and what the star is are two different things. The star *is* blue/white. When you look at it through the atmosphere, especially low to the horizon, then it may *appear* to be something else. You asked a question - you have the answer.
ProfRob
CC BY-SA 3.0
2017-10-11T11:43:09.990Z
@RobJeffries δ Sco, β Sco and π Sco were almost behind some not very close trees, so somewhat close to the horizon. Therefore υ Sco wasn't so low. It was the first time that I noticed it look SO red, and this called my attention. I would like if it could be confirmed by someone else (or at least discover why it appeared so red).
Rodrigo
CC BY-SA 3.0
2017-10-11T11:50:17.753Z
Actually it is *very* close to lambda Sco which is a brighter star. But just as blue/white.
ProfRob
CC BY-SA 3.0
2017-10-11T11:55:29.350Z
@RobJeffries Yes, together they form the "telson" of the scorpion, also known as "Cat's Eyes". Both were clearly visible, but only Upsilon was red.
Rodrigo
CC BY-SA 3.0
2017-10-11T12:00:39.523Z
Then it is a mystery since Upsilon Sco is a blue, non-varying star...
ProfRob
CC BY-SA 3.0
2017-10-13T07:09:16.547Z
The Sun is a yellow star but looks red near the horizon. No amount of second opinions will change the likelihood that the colour you saw is attributable to atmospheric effects.
Chappo Hasn't Forgotten
CC BY-SA 3.0
2017-10-13T13:47:32.777Z
@Chappo But the other stars in the constellation weren't red, even being lower on the horizon.
Rodrigo
CC BY-SA 3.0
2017-10-13T23:47:23.883Z
Then it is indeed a mystery! :-)
Chappo Hasn't Forgotten
<star><amateur-observing>
What's the color of Upsilon Scorpii?
Rodrigo
# What's the color of Upsilon Scorpii?

(Asked by: username_0 on 2017-10-11)

I was looking at the constellation Scorpius the other day, and noticed that the last star in the tail (the telson's tip) -- known as Upsilon Scorpii, υ Scorpii, or Lesath -- seemed yet more red than the "heart" of the scorpion -- Antares or Alpha Scorpii. Was it that I was drunk, or some kind of sky pollution? (Actually, a friend confirmed it was red, and she seemed sober than me.) Or is it, indeed, red? I couldn't find any information on-line. I saw [this database](http://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/icas/fchpix), but don't know how to find a star by its name, or if they have information about the color.

**Tags:** star, amateur-observing
> **Comments:**
> **username_0**: @RobJeffries The red color was confirmed by at least another person (see my edit). Is there any site like a on-line telescope?  
> **username_1**: Rodrigo, what you saw and what the star is are two different things. The star *is* blue/white. When you look at it through the atmosphere, especially low to the horizon, then it may *appear* to be something else. You asked a question - you have the answer.  
> **username_0**: @RobJeffries δ Sco, β Sco and π Sco were almost behind some not very close trees, so somewhat close to the horizon. Therefore υ Sco wasn't so low. It was the first time that I noticed it look SO red, and this called my attention. I would like if it could be confirmed by someone else (or at least discover why it appeared so red).  
> **username_1**: Actually it is *very* close to lambda Sco which is a brighter star. But just as blue/white.  
> **username_0**: @RobJeffries Yes, together they form the "telson" of the scorpion, also known as "Cat's Eyes". Both were clearly visible, but only Upsilon was red.  
> **username_1**: Then it is a mystery since Upsilon Sco is a blue, non-varying star...  
> **username_2**: The Sun is a yellow star but looks red near the horizon. No amount of second opinions will change the likelihood that the colour you saw is attributable to atmospheric effects.  
> **username_0**: @Chappo But the other stars in the constellation weren't red, even being lower on the horizon.  
> **username_2**: Then it is indeed a mystery! :-)  

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## 1 answers

### Answer by username_1 on 2022-10-22. Score: 2

Upsilon Sco is a blue/white (B-V =-0.17) B2 IV star according to the [SIMBAD](http://simbad.cds.unistra.fr/simbad/sim-id?Ident=Upsilon%20Sco&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit%20id) database entry.

As a slightly evolved B-type star it is unlikely to show any great variability and none has been recorded as far as I can see from a scan of the available references on the star. In fact it was included in a catalogue of the "least variable stars" by [Adelman (2001)](https://www.aanda.org/component/article?access=bibcode&bibcode=&bibcode=2001A%2526A...367..297AFUL), based on long duration monitoring by the Hipparcos satellite.

It might appear red if observed very low through a dusty atmosphere.


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