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I have seen the Gaia project from here which is about mapping the stars in the Milky Way galaxy. But I'm wondering if there is any open data on the positions (or something like "positions" since it probably not calculable now), or "coordinates", of the galaxies in the visible universe, as opposed to the stars. I wonder how animations such as this (a time=1m30s point it shows the galaxies zooming out from the Milky Way) get their data on the positions of the galaxies.

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  • $\begingroup$ The NASA/IPAC Extragalactic Database (aka NED) might be what you are looking for. It is fully searchable/queryable. $\endgroup$ – Rob Jeffries Nov 21 '18 at 20:40
  • $\begingroup$ @RobJeffries Thank you. Wondering if you know if they have an FTP or download or anything. It looks like NED might be an aggregation of other datasets (here), but maybe they offer this aggregated data in a nicer downloadable format somewhere. $\endgroup$ – Lance Pollard Nov 21 '18 at 21:09
  • $\begingroup$ It contains half a billion objects. $\endgroup$ – Rob Jeffries Nov 21 '18 at 23:15
  • $\begingroup$ The problem with entities like NED (and, to a slightly lesser degree HyperLEDA) is that they aggregate data from many different, heterogeneous sources. Big, nearby galaxies may have hundreds or even thousands of different types of data, including dozens of actual images and spectra and hundreds of literature references; very small, faint, and/or high-redshift galaxies might have little more than coordinates and a handful of brightness measurements. It's not something that can be organized into a single table for downloading. $\endgroup$ – Peter Erwin Nov 22 '18 at 9:22
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There are lots of galaxy catalogs.

If you're only interested in nearby galaxies, there are things like the Updated Nearby Galaxy Catalog; downloadable versions can be found here.

A classic all-sky galaxy catalog is the Third Reference Catalogue of Bright Galaxies (RC3, published in the early 1990s), which you can query here; if you follow the "FTP" links, you can find links to download the actual catalog.

(The HyperLEDA catalog that Dr. Chuck mentioned started as the RC3, but has various bits of data and re-classifications added more or less continuously since.)

A more recent catalog, based on the near-infrared observations of the 2 Micron All-Sky Survey (2MASS) is the 2MASS Galaxy Redshift Catalog, with about one million galaxies.

Even larger catalogs (though not covering the whole sky) can be found among the data products of the Sloan Digital Sky Survey, e.g. here

Many more catalogs exist, though some do not have accurate redshift information (meaning their distance from us is unknown or uncertain), and many are only for parts of the sky, sometimes very small regions (e.g., catalogs from Hubble Space Telescope observations).

(As for that video, I suspect very little is based on real data once you get beyond the Andromeda Galaxy...)

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  • $\begingroup$ Wondering where that nearby galaxy catalog data table can be downloaded, if it is this. $\endgroup$ – Lance Pollard Nov 21 '18 at 19:56
  • $\begingroup$ I am assuming the second link data download is here, though I wonder what that number 348 is, as there are a lot of numbers in the parent directory here, not sure which one is the right one, if they are just updates, or they each contain a latest release sort of thing. $\endgroup$ – Lance Pollard Nov 21 '18 at 19:59
  • $\begingroup$ Thanks for the note on the video, good to know I'm not missing something there. $\endgroup$ – Lance Pollard Nov 21 '18 at 20:00
  • $\begingroup$ There are 8 links to data on the last link here. I'm assuming the data you're mentioning is scattered throughout those places. $\endgroup$ – Lance Pollard Nov 21 '18 at 20:03
  • $\begingroup$ File to download some stuff irsa.ipac.caltech.edu/data/Planck/release_2/all-sky-maps/… $\endgroup$ – Lance Pollard Nov 21 '18 at 20:07
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There is the Uppsala General Catalog of Galaxies

It has galaxies down to 19 magnitude. It doesn't have distances, but it does have radial velocity.

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  • $\begingroup$ Nice, wondering if you wouldn't mind explaining how to download the data. It lead me here, so it seems the ASCII representation is all here I'm guessing. $\endgroup$ – Lance Pollard Nov 21 '18 at 9:22
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There is the HyperLeda catalog http://leda.univ-lyon1.fr/, which has about 5 million galaxies, with redshift for about 3 million (if I understand the summary).

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  • $\begingroup$ Awesome! So here's where I went from there (clicking in "Basic Data"): 1 -> 2, 3, 4 (nice picture, but don't see where the data is yet). Please explain how to download all of the data at once, maybe there is an FTP site or something, though it doesn't look like it :/ $\endgroup$ – Lance Pollard Nov 21 '18 at 9:16
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    $\begingroup$ Lance, I don’t have any experience using the data. Sorry I can’t help. $\endgroup$ – Dr Chuck Nov 21 '18 at 9:45

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