<p>The article in <em>La Montagne</em> seems to refer to this <a href="https://www.cieletespace.fr/actualites/deja-plus-de-700-amateurs-mobilises-en-france-pour-observer-l-asteroide-eurybate" rel="nofollow noreferrer"><em>Ciel et Espace</em> article</a>,
which links to a Twitter thread including <a href="https://twitter.com/EricLagadec/status/1578377369995329541" rel="nofollow noreferrer">an image</a> from the <em>Ciel et Espace</em> print edition.
That article mentions two occultations:
one by Titan in July 1989, visible in Europe;
and one by <a href="https://en.wikipedia.org/wiki/2_Pallas" rel="nofollow noreferrer">Pallas</a> in May 1983, visible in the US.</p>
<p><a href="https://ui.adsabs.harvard.edu/abs/1990AJ.....99.1636D/abstract" rel="nofollow noreferrer">Dunham et al. 1990</a> analyzed the 1983 event.
Their main result was a 2D profile of Pallas with only 1.2 km uncertainty, which enabled a decent 3D estimate when combined with a 1978 occultation.
They also characterized the reaction times of visual observers by method and experience level.
They further estimated the separation of the occulted binary star <a href="https://en.wikipedia.org/wiki/1_Vulpeculae" rel="nofollow noreferrer">1 Vulpeculae</a> and found that its parallax had been overestimated.</p>
<p><img src="https://i.sstatic.net/yhWiE.png" alt="Dunham 1990 figure 2: Raw occultation observations." /></p>
<p>A preliminary report appears in IOTA <a href="https://occultations.org/pub/newsletters/occultation-newsletter/" rel="nofollow noreferrer">Occultation Newsletter</a> vol. 3 no. 4, July 1983.</p>

CC BY-SA 4.0
2023-12-28T10:38:14.033Z
Thanks! If you could include a summary of this Dunham et al. paper in your answer (especially the citizen science bits), that'd be great!
Jean-Marie Prival
CC BY-SA 4.0
2024-01-02T14:28:54.720Z
Thanks! Unfortunately I was away from the web when the bounty expired, so it has been automatically awarded. Maybe timing the bounty during the holidays was not an ideal move...
Jean-Marie Prival
CC BY-SA 4.0
2024-01-02T14:52:00.047Z
@Jean-MariePrival I'm [addicted](https://data.stackexchange.com/stackoverflow/query/1133591/users-offering-the-most-reputation-through-bounties-networkwide) (also [screenshot](https://i.sstatic.net/GHrFD.png)) to [bountying](https://english.stackexchange.com/q/546030/217285); if you don't mind, I'll add one here.
uhoh
CC BY-SA 4.0
2024-01-02T16:28:45.750Z
@uhoh The green check mark is enough for me. :)
Mike G
CC BY-SA 4.0
2024-01-02T20:46:32.003Z
@uhoh Sure, go ahead if you want. You have an impressive record!
Jean-Marie Prival
CC BY-SA 4.0
2024-01-02T22:23:27.237Z
@MikeG I know, but I have this compulsion to "set the universe right" in what ever little ways I can.
uhoh
CC BY-SA 4.0
2023-12-27T18:56:22.097Z
2023-12-29T15:05:22.993Z
2023-12-29T15:05:22.993Z
Mike G
<p>What seems to be referenced here is the International Occultation Timing Association-<a href="https://occultations.org/" rel="nofollow noreferrer">IOTA</a></p>
<p>They were set up in 1983, and from their website</p>
<blockquote>
<p>IOTA is a volunteer science and research organization born in 1983.  We gather data from timings of astronomical occultations and provide a variety of educational resources to promote and encourage observations of astronomical occultations.</p>
</blockquote>
<p>There are some research papers that reference this: <a href="https://www.boulder.swri.edu/binary-mtg/abstracts/maley.pdf" rel="nofollow noreferrer">Evidence for asteroidal satellites from 30 years of occultation observations</a></p>
<p>Although I must say they do not seem to be very big overall, which may be why you did not find them.</p>
<p>Hope this helps :)</p>

CC BY-SA 4.0
2023-12-28T10:40:25.460Z
Thank you, I had indeed missed this IOTA. The link abstract doesn't contain much info... But I see they have newsletter archives dating back to the 80's on their website, I'll dig into them.
Jean-Marie Prival
CC BY-SA 4.0
2023-12-27T15:38:52.473Z
2023-12-28T11:56:31.020Z
2023-12-28T11:56:31.020Z
hi-bye125
<p>The news story &quot;<a href="https://www.lamontagne.fr/limoges-87000/loisirs/une-etoile-eclipsee-par-un-asteroide-ce-week-end-en-france-comment-et-pourquoi-les-scientifiques-vous-demandent-de-l-observer_14204267/" rel="nofollow noreferrer">A star eclipsed by an asteroid in France this week-end: how and why scientists ask you to observe it</a>&quot; (in French) relates how people were are asked to look at the occultation of HD 51593 by asteroid Eurybates, one of the targets of space probe Lucy. The article explains how multiple observations of this occultation could help refine Eurybates' trajectory. The last paragraph states (my translation):</p>
<blockquote>
<p>More than 700 willing observers have already registered for this
week-end. Similar experiences in the late 80's in the US didn't reach
more than 200 observers...</p>
</blockquote>
<p>But there is no source to this claim, and the linked page of the French Astronomy Association, organizing this citizen science project, does not mention it. So I'd like to ask:</p>
<p><strong>Which citizen science occultation experiences were done in the late 80's in the US? What were the achievements of these experiences?</strong></p>

CC BY-SA 4.0
2022-10-22T16:23:19.503Z
Pretty impressive that they coordinated 200 people pre-internet.
Jon Custer
CC BY-SA 4.0
2022-10-22T17:32:37.430Z
I'm not in the USA, but I *vaguely* remember amateurs contributing to measurements of lunar occultations of stars.
PM 2Ring
CC BY-SA 4.0
2022-10-23T00:25:43.197Z
In the 1970's I remember reading about upcoming occultations of different types and am pretty sure there were invitations to send timing data by post. There were occasional offers to send predictions to anyone who mailed a letter with their lat/lon coordinates and elevation, which was a fun challenge for a kid before personal GPS receivers; it was a trip to the library. I got one prediction back with an apology for being late; "I left the letters in my banjo case playing with my bluegrass band" it mentioned. I think this was someone from NASA/JPL. I was impressed: "NASA folks are people too!"
uhoh
CC BY-SA 4.0
2022-10-27T15:20:31.540Z
@uhoh Thank you for your input, I appreciate it even if (or because?) it is anecdotal! :)
Jean-Marie Prival
CC BY-SA 4.0
2023-01-19T18:40:20.017Z
Did you already contact the authors of the news article?
Grimaldi
CC BY-SA 4.0
2023-12-27T16:24:35.093Z
IOTA has a mailing list you can join and ask there: https://groups.io/g/IOTAoccultations/
Greg Miller
<observational-astronomy><amateur-observing><asteroids><occultation>
Which citizen science occultation experiences were done in the late 80's in the US? With what results?
Jean-Marie Prival
# Which citizen science occultation experiences were done in the late 80's in the US? With what results?

(Asked by: username_0 on 2022-10-21)

The news story "[A star eclipsed by an asteroid in France this week-end: how and why scientists ask you to observe it](https://www.lamontagne.fr/limoges-87000/loisirs/une-etoile-eclipsee-par-un-asteroide-ce-week-end-en-france-comment-et-pourquoi-les-scientifiques-vous-demandent-de-l-observer_14204267/)" (in French) relates how people were are asked to look at the occultation of HD 51593 by asteroid Eurybates, one of the targets of space probe Lucy. The article explains how multiple observations of this occultation could help refine Eurybates' trajectory. The last paragraph states (my translation):

> More than 700 willing observers have already registered for this
> week-end. Similar experiences in the late 80's in the US didn't reach
> more than 200 observers...

But there is no source to this claim, and the linked page of the French Astronomy Association, organizing this citizen science project, does not mention it. So I'd like to ask:

**Which citizen science occultation experiences were done in the late 80's in the US? What were the achievements of these experiences?**

**Tags:** observational-astronomy, amateur-observing, asteroids, occultation
> **Comments:**
> **username_1**: Pretty impressive that they coordinated 200 people pre-internet.  
> **username_2**: I'm not in the USA, but I *vaguely* remember amateurs contributing to measurements of lunar occultations of stars.  
> **username_3**: In the 1970's I remember reading about upcoming occultations of different types and am pretty sure there were invitations to send timing data by post. There were occasional offers to send predictions to anyone who mailed a letter with their lat/lon coordinates and elevation, which was a fun challenge for a kid before personal GPS receivers; it was a trip to the library. I got one prediction back with an apology for being late; "I left the letters in my banjo case playing with my bluegrass band" it mentioned. I think this was someone from NASA/JPL. I was impressed: "NASA folks are people too!"  
> **username_0**: @uhoh Thank you for your input, I appreciate it even if (or because?) it is anecdotal! :)  
> **username_4**: Did you already contact the authors of the news article?  
> **username_5**: IOTA has a mailing list you can join and ask there: https://groups.io/g/IOTAoccultations/  

---

## 2 answers

### Answer by username_6 on 2023-12-27. Score: 2 | Accepted answer

The article in *La Montagne* seems to refer to this [*Ciel et Espace* article](https://www.cieletespace.fr/actualites/deja-plus-de-700-amateurs-mobilises-en-france-pour-observer-l-asteroide-eurybate),
which links to a Twitter thread including [an image](https://twitter.com/EricLagadec/status/1578377369995329541) from the *Ciel et Espace* print edition.
That article mentions two occultations:
one by Titan in July 1989, visible in Europe;
and one by [Pallas](https://en.wikipedia.org/wiki/2_Pallas) in May 1983, visible in the US.

[Dunham et al. 1990](https://ui.adsabs.harvard.edu/abs/1990AJ.....99.1636D/abstract) analyzed the 1983 event.
Their main result was a 2D profile of Pallas with only 1.2 km uncertainty, which enabled a decent 3D estimate when combined with a 1978 occultation.
They also characterized the reaction times of visual observers by method and experience level.
They further estimated the separation of the occulted binary star [1 Vulpeculae](https://en.wikipedia.org/wiki/1_Vulpeculae) and found that its parallax had been overestimated.

![Dunham 1990 figure 2: Raw occultation observations.](https://i.sstatic.net/yhWiE.png)

A preliminary report appears in IOTA [Occultation Newsletter](https://occultations.org/pub/newsletters/occultation-newsletter/) vol. 3 no. 4, July 1983.

> **Comments:**
> **username_0**: Thanks! If you could include a summary of this Dunham et al. paper in your answer (especially the citizen science bits), that'd be great!  
> **username_0**: Thanks! Unfortunately I was away from the web when the bounty expired, so it has been automatically awarded. Maybe timing the bounty during the holidays was not an ideal move...  
> **username_3**: @Jean-MariePrival I'm [addicted](https://data.stackexchange.com/stackoverflow/query/1133591/users-offering-the-most-reputation-through-bounties-networkwide) (also [screenshot](https://i.sstatic.net/GHrFD.png)) to [bountying](https://english.stackexchange.com/q/546030/217285); if you don't mind, I'll add one here.  
> **username_6**: @uhoh The green check mark is enough for me. :)  
> **username_0**: @uhoh Sure, go ahead if you want. You have an impressive record!  
> **username_3**: @MikeG I know, but I have this compulsion to "set the universe right" in what ever little ways I can.  

---

### Answer by username_7 on 2023-12-27. Score: 3

What seems to be referenced here is the International Occultation Timing Association-[IOTA](https://occultations.org/)

They were set up in 1983, and from their website

> IOTA is a volunteer science and research organization born in 1983. We gather data from timings of astronomical occultations and provide a variety of educational resources to promote and encourage observations of astronomical occultations.

There are some research papers that reference this: [Evidence for asteroidal satellites from 30 years of occultation observations](https://www.boulder.swri.edu/binary-mtg/abstracts/maley.pdf)

Although I must say they do not seem to be very big overall, which may be why you did not find them.

Hope this helps :)

> **Comments:**
> **username_0**: Thank you, I had indeed missed this IOTA. The link abstract doesn't contain much info... But I see they have newsletter archives dating back to the 80's on their website, I'll dig into them.  

---

