The fantastic astrophotographer André vd Hoeven sent me a note recently saying he had been playing with a new lens he bought, and wanted to attach it directly to a CCD camera – a digital detector like a store-bought camera, but designed specifically for astrophotography. Usually those are mounted on the back of a telescope, but with a camera lens on it the assembly takes very wide angle shots of the sky.
How wide? Well, he made a 4×4 mosaic of the entire summer constellation of Cygnus the Swan, and it’s breathtaking:
[Click to enanatidaenate, or get the massive 6200 x 5200 pixel version.]
Yegads! He used a filter on the camera that lets through the light of warm hydrogen, so it picks up the gas floating between the stars. So besides the stars in the picture you also see huge amounts of interstellar gas from exploding stars, stars being born, stars lighting up the material around them… it’s amazing.
He helpfully created an annotated version that explains what you’re seeing: