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The Stars, Like Dust

Submitted by Kevin Jardine on 14 October, 2016 - 13:15

The stars, like dust, encircle me
In living mists of light;
And all of space I seem to see
In one vast burst of sight.

Isaac Asimov

September 14, 2016 was the day when everything changed in astronomy with the release of parallax estimates for more than 2 million stars. My last few blog posts have covered the momentous release of the Tycho-Gaia Astrometric Solution (TGAS) as part of Gaia DR1.

Today I have put up the Tycho Explorer, a zoomable, pannable, clickable interface to the Tycho-2 catalog, both as it appears in the sky (Tycho Sky) and as it appears as a face-on map of the galactic plane (Tycho Galaxy).

Tycho Sky includes 2.5 million stars from the Tycho-2 catalog with provided B and V magnitudes (which is almost all of them), and Tycho Galaxy includes more than a million of these stars with reasonably low parallax errors (measured error/parallax ratio < 0.2) stretching out to a distance of about 700 parsecs (2300 light years). At the highest zoom level you can click on each star to get more information and use links to see the star in Tycho Sky and Tycho Galaxy. Search boxes enable you to zoom into a star in the maps by entering an identifier.

Much more information about both the sky and face-on Tycho viewers can be found by clicking the Help links at the upper right of the viewers. The Tycho Explorer is still very much in beta. The infrared background to Tycho Sky has a number of artifacts and limitations, and not all the functions work yet on mobile devices. TGAS itself does not include any naked eye stars or many stars close to the Sun. I'll mention the limitations in more detail in my next blog post.

The Tycho Explorer will continue to improve and the next Gaia data release at the end of 2017 will have more and more accurate data.

Despite the limitations, the results are already amazing. We are on the verge of the greatest mapping project in human history - one that dwarfs that of the New World. The Milky Way is appearing in all its glory before our eyes.

You can download a 4K wallpaper image of some of Tycho Galaxy here (warning, 10 Mb file).

Update: I think I have fixed the issues for mobile and the Tycho Explorer should now work for Android and iOS devices. The interface is not very convenient for small screens (I recommend a large monitor - it looks spectacular on my 4K Philips monitor). If there is demand I might work on a tailored interface for phones.

The code is now in GitHub: Contributions are welcome.