allsky

"allsky" is a project to visualize the bulk galactic motions and properties of stars. It is built off of the "earth" package developed by Cameron Beccario, to whom we are entirely indebted, which itself is based on the earlier Tokyo Wind Map project.

Building and Launching

After installing node.js and npm, clone "allsky" and install the associated dependencies:

git clone https://github.com/cambecc/earth
cd earth
npm install

After that is done, launch the development web server:

node dev-server.js 8080

Note that you might need to use nodejs instead of node due to a possible naming conflict for Ubuntu, Mint, and/or elementary OS users.

Finally, point your browser to:

http://localhost:8080

All relevant files are located in the public directory. See public/index.html and public/libs/earth/*.js for the main entry points. Data files are located in the public/data directory. These are currently named after existing weather hooks in the codebase and so are essentially non-sensical. To see what things refer to what, use the menu in the index.html file or email jspeagle@cfa.harvard.edu.

Most of the structure used in "allsky" follows that of "earth", so if there are issues that appear unaddressed please check whether they are discussed there before raising a new one.

Notes

• To produce smooth behavior, bilinear interpolation is used. While the default resolution of our data is constructed using an nside=64 healpix scheme (roughly 1 degree on the sky) and then interpolated to a 1 degree grid in Galactic longitude and latitude, the cost of doing this can start becoming prohibitive at higher resolutions.
• Various projections warp and distort the sphere in various ways. Accounting for this requires the use of finite difference approximations that are computed during interpolation.
• Velocity stream animations do not scale linearly with the actual underlying tangential velocities in order to accomodate the broad range of observed values as a function of distance.
• For visualization purposes only, all data is smoothed with a Gaussian beam with a FWHM of 0.01 radians (~30 arcmin).

Inspiration

This work was inspired (and built off of) the wonderful "earth" project. "earth" was itself inspired by the hint.fm wind map and D3.js visualization library.