<p>This particular object I tracked down by comparing the visual with the infrared image of the sky. It was a little tricky because no very bright star appears at that location. But after making comparisons, the star in the original image is <a href="http://simbad.u-strasbg.fr/simbad/sim-id?Ident=HD%20155161&amp;NbIdent=1&amp;Radius=2&amp;Radius.unit=arcmin&amp;submit=submit%20id" rel="nofollow noreferrer">HD 155161</a>, also known as V* AH Sco, indicating that it is a variable. </p>

<p>In fact, Simbad lists it as a red supergiant at coordinates [17 11 17.02114,  -32 19 30.7132], and visual magnitude of about 7.5 Red supergiants are often unstable and are semi-regular varible stars.</p>

<p>That explains why it is much brighter in the VISTA infrared image than in the optical. Red supergiants have cool outer layers that give off much of their radiation as infrared, not as visible light.</p>

<p>Looking at the <a href="http://aladin.u-strasbg.fr/AladinLite/?target=V*%20AH%20Sco&amp;fov=0.52&amp;survey=P%2F2MASS%2Fcolor" rel="nofollow noreferrer">star on Aladin Lite</a>, even in the infrared, there is not a hint of nebulosity around the star. The conclusion is that this is an optical effect, lens flare or similar.</p>

CC BY-SA 3.0
2017-07-29T15:08:14.890Z
2017-07-29T15:20:00.407Z
2017-07-29T15:20:00.407Z
James K
<p>As the comments have said, this is simply a camera effect known as a <a href="https://en.wikipedia.org/wiki/Lens_flare" rel="nofollow noreferrer">lens flare</a></p>
<p>If you look around at the various bright stars, you can see this in multiple places, e.g.:</p>
<p><a href="https://i.sstatic.net/SBB2o.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/SBB2o.jpg" height="300"/></a><br />
<sub>(source: <a href="https://snag.gy/SGyKUu.jpg" rel="nofollow noreferrer">snag.gy</a>)</sub></p>
<p>and also:</p>
<img src="https://snag.gy/5DtdHW.jpg" height="300" />

CC BY-SA 3.0
2017-07-28T12:02:23.410Z
Do you know if lens flare can account for the reddish region to the left of the star?
HDE 226868
CC BY-SA 3.0
2017-07-28T12:22:37.500Z
@HDE226868 I think so. You can a reddish colour on the edge of the flare of the bottom image.
Beta Decay
CC BY-SA 4.0
2017-07-27T19:04:18.430Z
2021-01-01T18:54:56.700Z
2021-01-01T18:54:56.700Z
Beta Decay
<p>I was going through the <a href="https://www.eso.org/public/images/eso1242a/zoomable" rel="nofollow noreferrer">zoomable image of Milky way</a> and after zooming to this particular location, we can see a reddish area on the left side of a probably large star. Here is a screenshot I took after zooming to that particular area:
 <a href="https://i.sstatic.net/GWYHM.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/GWYHM.jpg" alt="image"></a></p>

<p>So is this gas cloud or some weird lens effect ?</p>

<p>Edit: Location ( center of the blue rectangle )</p>

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

CC BY-SA 3.0
2017-07-25T11:46:02.670Z
Can you give the location... ?
ProfRob
CC BY-SA 3.0
2017-07-25T11:54:58.697Z
@RobJeffries, I have edited and added an image. The particular object is at the top right. Thanks.
astre
CC BY-SA 3.0
2017-07-25T12:44:57.877Z
The coordinates !
ProfRob
CC BY-SA 3.0
2017-07-25T12:49:15.617Z
Sorry but I don't know how to get coordinates on that site. Any idea how to ?
astre
CC BY-SA 3.0
2017-07-25T13:26:09.297Z
The horizontal and vertical bar make it look lensy to me. There's plenty of spikes on even the less bright stars.
Wayfaring Stranger
CC BY-SA 3.0
2017-07-25T14:05:47.613Z
It's just a reflection nebula but I can't work out which bright star it is. I assume that galactic N is towards the top?
ProfRob
CC BY-SA 3.0
2017-07-25T14:08:52.430Z
What wavelength(s) is the image taken at?
HDE 226868
CC BY-SA 3.0
2017-07-26T07:23:25.660Z
Given that this is a mosaic of multiple images, I'd be inclined to say that particular part of the image simply has classic [lens flare](http://www.cambridgeincolour.com/tutorials/lens-flare.htm).
StephenG - Help Ukraine
CC BY-SA 3.0
2017-07-27T18:57:42.000Z
Looks like J. J. Abrams took this picture
Beta Decay
CC BY-SA 3.0
2017-07-28T03:54:12.783Z
@BetaDecay I literally lol'ed.
uhoh
<nebula><gas>
Is this gas cloud or lens effect?
astre
# Is this gas cloud or lens effect?

(Asked by: username_0 on 2017-07-25)

I was going through the [zoomable image of Milky way](https://www.eso.org/public/images/eso1242a/zoomable) and after zooming to this particular location, we can see a reddish area on the left side of a probably large star. Here is a screenshot I took after zooming to that particular area:
[![image](https://i.sstatic.net/GWYHM.jpg)](https://i.sstatic.net/GWYHM.jpg)

So is this gas cloud or some weird lens effect ?

Edit: Location ( center of the blue rectangle )

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

**Tags:** nebula, gas
> **Comments:**
> **username_1**: Can you give the location... ?  
> **username_0**: @RobJeffries, I have edited and added an image. The particular object is at the top right. Thanks.  
> **username_1**: The coordinates !  
> **username_0**: Sorry but I don't know how to get coordinates on that site. Any idea how to ?  
> **username_2**: The horizontal and vertical bar make it look lensy to me. There's plenty of spikes on even the less bright stars.  
> **username_1**: It's just a reflection nebula but I can't work out which bright star it is. I assume that galactic N is towards the top?  
> **username_3**: What wavelength(s) is the image taken at?  
> **username_4**: Given that this is a mosaic of multiple images, I'd be inclined to say that particular part of the image simply has classic [lens flare](http://www.cambridgeincolour.com/tutorials/lens-flare.htm).  
> **username_5**: Looks like J. J. Abrams took this picture  
> **username_6**: @BetaDecay I literally lol'ed.  

---

## 2 answers

### Answer by username_7 on 2017-07-29. Score: 1 | Accepted answer

This particular object I tracked down by comparing the visual with the infrared image of the sky. It was a little tricky because no very bright star appears at that location. But after making comparisons, the star in the original image is [HD 155161](http://simbad.u-strasbg.fr/simbad/sim-id?Ident=HD%20155161&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit%20id), also known as V\* AH Sco, indicating that it is a variable.

In fact, Simbad lists it as a red supergiant at coordinates [17 11 17.02114, -32 19 30.7132], and visual magnitude of about 7.5 Red supergiants are often unstable and are semi-regular varible stars.

That explains why it is much brighter in the VISTA infrared image than in the optical. Red supergiants have cool outer layers that give off much of their radiation as infrared, not as visible light.

Looking at the [star on Aladin Lite](http://aladin.u-strasbg.fr/AladinLite/?target=V*%20AH%20Sco&fov=0.52&survey=P%2F2MASS%2Fcolor), even in the infrared, there is not a hint of nebulosity around the star. The conclusion is that this is an optical effect, lens flare or similar.


---

### Answer by username_5 on 2017-07-27. Score: 1

As the comments have said, this is simply a camera effect known as a [lens flare](https://en.wikipedia.org/wiki/Lens_flare)

If you look around at the various bright stars, you can see this in multiple places, e.g.:

[![](https://i.sstatic.net/SBB2o.jpg)](https://i.sstatic.net/SBB2o.jpg)  
(source: [snag.gy](https://snag.gy/SGyKUu.jpg))

and also:

![](https://snag.gy/5DtdHW.jpg)

> **Comments:**
> **username_3**: Do you know if lens flare can account for the reddish region to the left of the star?  
> **username_5**: @HDE226868 I think so. You can a reddish colour on the edge of the flare of the bottom image.  

---

