<p>Only by knowing what kind of a star it is, or by inferring that information from the available colours. From there you use a photometric or spectroscopic parallax calibration. ie. There is a relationship between the absolute magnitude and colours of a main sequence star. Of course there is no guarantee you are looking at a main sequence star.</p>

<p>You can get more idea by cross correlating with the 2MASS JHK catalogue, as the J-H vs H-K colours of giants are usually distinctive.</p>

<p>More specific help needs a more specific question.</p>

CC BY-SA 3.0
2015-05-10T20:08:18.413Z
2015-05-10T20:08:18.413Z
ProfRob
<p>I'm looking at the <a href="http://www.iphas.org/dr2/#download" rel="nofollow">IPHAS DR2</a> catalog. It has the Right Ascension and Declination but I'm not seeing any distance information (lightyears or parsecs). I'm wondering, given the columns in the dataset, if the distance can be calculated.</p>

<distances>
Is it possible to get the distance to a star in the IPHAS DR2 catalog?
Justin808
# Is it possible to get the distance to a star in the IPHAS DR2 catalog?

(Asked by: username_0 on 2015-05-08)

I'm looking at the [IPHAS DR2](http://www.iphas.org/dr2/#download) catalog. It has the Right Ascension and Declination but I'm not seeing any distance information (lightyears or parsecs). I'm wondering, given the columns in the dataset, if the distance can be calculated.

**Tags:** distances

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## 1 answers

### Answer by username_1 on 2015-05-10. Score: 2

Only by knowing what kind of a star it is, or by inferring that information from the available colours. From there you use a photometric or spectroscopic parallax calibration. ie. There is a relationship between the absolute magnitude and colours of a main sequence star. Of course there is no guarantee you are looking at a main sequence star.

You can get more idea by cross correlating with the 2MASS JHK catalogue, as the J-H vs H-K colours of giants are usually distinctive.

More specific help needs a more specific question.


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