April 2020

Star Chart is an astronomical data mashup that can produce accurate star positions for any time and location.

Star Chart came about as a continuation of an earlier project where I visualized the positions of the ~120,000 stars in the HYG 3.0 database. In the previous version, I plotted the stars in 3D space and set the camera location where our sun is positioned. For this update, I wanted to be able to create a view of the night sky from any latitude/longitude and any date/time. This would allow you to see what the sky looked like at the time of your birth or which constellation was overhead when you first learned about Covid-19.

Flattening the stars down to a plane required that I look into planar projection options. I first tried orthographic projection, but eventually settled on stereographic projection because it seems more common in star charts.

I was able to add details like constellation lines and boundary regions by cross referencing a couple different databases:

• Constellation boundaries: Catalogue of Constellation Boundary Data (1989) 
  
• Constellation lines and names: Stellarium Github repo.

Next Steps

I'd like to create prints from this setup but there are already plenty of services that produce this type of star chart. I am thinking about exploring ways to produce prints of this system using a computer controlled plotter.