<p>The most interesting question related to this <a href="https://twitter.com/WKCosmo/status/1208500846834700290" rel="nofollow noreferrer">Will Kinney tweet</a> would be <em>what's going on with Betelgeuse?</em> but I can't help but wonder why <strong>much but not all</strong> of the photometric data is clustered in increments of 0.1 magnitude.</p>

<p><a href="https://astronomy.stackexchange.com/a/25742/7982">These stripes</a> were the result of posting some preliminary data where analysis had some ultimately uninteresting effect that later disappeared, but I don't think that's the case here.</p>

<hr>

<blockquote>
  <p>So I downloaded data on Betelgeuse from @AAVSO . Here's a plot of visual magnitude vs Julian date for the last 10 years. Clearly something very strange going on -- a whole lot of anomalous dimming happening very quickly, in the last few months.</p>
</blockquote>

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

CC BY-SA 4.0
2019-12-26T15:03:41.323Z
[Giant star's odd behaviour fuels speculation it's about to explode](https://www.newshub.co.nz/home/world/2019/12/giant-star-s-odd-behaviour-fuels-speculation-it-s-about-to-explode.html)
uhoh
CC BY-SA 4.0
2019-12-26T15:26:10.547Z
I guess because the magnitudes are measured to the nearest 0.1 mag. Quite likely if these are just visual estimates.
ProfRob
CC BY-SA 4.0
2019-12-26T21:18:46.433Z
Since there's quite a few data points that also align to multiples of .25 as well, some that align to multiples of .05, and a minority that have finer resolution, I would assume that the data is taken from multiple observers.  The most common type of observer just has a resolution at .1 mag.
Ghedipunk
CC BY-SA 4.0
2020-09-21T03:11:30.440Z
@Ghedipunk I'd definitely *accept* an answer like that; if these are visual and not photometric observations that makes 100% sense. I'd originally assumed they were photometric and/or there was some processing funnybusiness [like this](https://astronomy.stackexchange.com/q/25736/7982) going on.
uhoh
<observational-astronomy><photometry><variable-star>
Why do these photometric observations of Betelgeuse look "quantized" in 0.1 magnitude steps?
uhoh
# Why do these photometric observations of Betelgeuse look "quantized" in 0.1 magnitude steps?

(Asked by: username_0 on 2019-12-26)

The most interesting question related to this [Will Kinney tweet](https://twitter.com/WKCosmo/status/1208500846834700290) would be *what's going on with Betelgeuse?* but I can't help but wonder why **much but not all** of the photometric data is clustered in increments of 0.1 magnitude.

[These stripes](https://astronomy.stackexchange.com/a/25742/7982) were the result of posting some preliminary data where analysis had some ultimately uninteresting effect that later disappeared, but I don't think that's the case here.

---

> So I downloaded data on Betelgeuse from @AAVSO . Here's a plot of visual magnitude vs Julian date for the last 10 years. Clearly something very strange going on -- a whole lot of anomalous dimming happening very quickly, in the last few months.

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

**Tags:** observational-astronomy, photometry, variable-star
> **Comments:**
> **username_0**: [Giant star's odd behaviour fuels speculation it's about to explode](https://www.newshub.co.nz/home/world/2019/12/giant-star-s-odd-behaviour-fuels-speculation-it-s-about-to-explode.html)  
> **username_1**: I guess because the magnitudes are measured to the nearest 0.1 mag. Quite likely if these are just visual estimates.  
> **username_2**: Since there's quite a few data points that also align to multiples of .25 as well, some that align to multiples of .05, and a minority that have finer resolution, I would assume that the data is taken from multiple observers.  The most common type of observer just has a resolution at .1 mag.  
> **username_0**: @Ghedipunk I'd definitely *accept* an answer like that; if these are visual and not photometric observations that makes 100% sense. I'd originally assumed they were photometric and/or there was some processing funnybusiness [like this](https://astronomy.stackexchange.com/q/25736/7982) going on.  

---

## 0 answers

