<p>The <a href="https://ui.adsabs.harvard.edu/abs/1904AnOBN...8a...1N/abstract" rel="nofollow noreferrer">Niesten 1904</a> double star catalog explains its tables on <a href="http://articles.adsabs.harvard.edu//full/1904AnOBN...8a...1N/0000015.000.html" rel="nofollow noreferrer">page 2</a>:</p>

<p><img src="https://i.sstatic.net/0cfgq.png" alt="Catalogue explanation in French"></p>

<p>The entry in question is for <a href="https://en.wikipedia.org/wiki/Mintaka" rel="nofollow noreferrer">&delta; Orionis</a>.</p>

<p>"A = 2" means the primary component was estimated at <a href="https://en.wikipedia.org/wiki/Apparent_magnitude" rel="nofollow noreferrer">apparent magnitude</a> 2.</p>

<p>"1879,12" is an observation date in fractional years, using a comma as a decimal point.</p>

<p>"163,0" and "161,7" are <a href="http://articles.adsabs.harvard.edu//full/1904AnOBN...8a...1N/0000015.000.html" rel="nofollow noreferrer">position angles</a> from the primary component to the secondary, in degrees counterclockwise from celestial north.
The * indicates an observation by Stuyvaert instead of Niesten.
"162,35" is an average of the two observations.</p>

<p>"en contact" means the separation between the two was smaller than the telescope's <a href="https://en.wikipedia.org/wiki/Angular_resolution" rel="nofollow noreferrer">angular resolution</a>. Otherwise their separation would be given in arcseconds.</p>

CC BY-SA 4.0
2019-09-16T04:15:44.867Z
Thank you very much
Arrara
CC BY-SA 4.0
2019-09-14T05:55:29.570Z
2019-09-14T05:55:29.570Z
Mike G
<p>What do this data mean please?</p>

<p><a href="http://cdsads.u-strasbg.fr/cgi-bin/nph-iarticle_query?1904AnOBN...8a...1N&amp;data_type=PDF_HIGH&amp;whole_paper=YES&amp;type=PRINTER&amp;filetype=.pdf" rel="nofollow noreferrer">http://cdsads.u-strasbg.fr/cgi-bin/nph-iarticle_query?1904AnOBN...8a...1N&amp;data_type=PDF_HIGH&amp;whole_paper=YES&amp;type=PRINTER&amp;filetype=.pdf</a> </p>

<p><a href="https://i.sstatic.net/7uFjF.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/7uFjF.png" alt="enter image description here"></a></p>

CC BY-SA 4.0
2019-09-14T05:46:34.500Z
You should explain what it is that you do understand about the paper first, and demonstrate that you've put some effort into understanding it. This looks like a tiny crop from a random page from a 42 page paper, written in French, possibly a century ago.
uhoh
<positional-astronomy>
Data in measures paper
Arrara
# Data in measures paper

(Asked by: username_0 on 2019-09-14)

What do this data mean please?

<http://cdsads.u-strasbg.fr/cgi-bin/nph-iarticle_query?1904AnOBN...8a...1N&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf>

[![enter image description here](https://i.sstatic.net/7uFjF.png)](https://i.sstatic.net/7uFjF.png)

**Tags:** positional-astronomy
> **Comments:**
> **username_1**: You should explain what it is that you do understand about the paper first, and demonstrate that you've put some effort into understanding it. This looks like a tiny crop from a random page from a 42 page paper, written in French, possibly a century ago.  

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## 1 answers

### Answer by username_2 on 2019-09-14. Score: 3 | Accepted answer

The [Niesten 1904](https://ui.adsabs.harvard.edu/abs/1904AnOBN...8a...1N/abstract) double star catalog explains its tables on [page 2](http://articles.adsabs.harvard.edu//full/1904AnOBN...8a...1N/0000015.000.html):

![Catalogue explanation in French](https://i.sstatic.net/0cfgq.png)

The entry in question is for [δ Orionis](https://en.wikipedia.org/wiki/Mintaka).

"A = 2" means the primary component was estimated at [apparent magnitude](https://en.wikipedia.org/wiki/Apparent_magnitude) 2.

"1879,12" is an observation date in fractional years, using a comma as a decimal point.

"163,0" and "161,7" are [position angles](http://articles.adsabs.harvard.edu//full/1904AnOBN...8a...1N/0000015.000.html) from the primary component to the secondary, in degrees counterclockwise from celestial north.
The \* indicates an observation by Stuyvaert instead of Niesten.
"162,35" is an average of the two observations.

"en contact" means the separation between the two was smaller than the telescope's [angular resolution](https://en.wikipedia.org/wiki/Angular_resolution). Otherwise their separation would be given in arcseconds.

> **Comments:**
> **username_0**: Thank you very much  

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