4 ms·

Betelgeuse is ~47 milliarcseconds in diameter, making it one of the largest stars (in angular diameter terms) observable from Earth. It was first resolved using

Betelgeuse is ~47 milliarcseconds in diameter, making it one of the largest stars (in angular diameter terms) observable from Earth. It was first resolved using the Michelson Stellar Interferometer (which had a diameter of 20 meters) in the 1880s. I don't know the observational wavelength for the images in the article (VLT-SPHERE has filters that go from ~1-2 microns), but if the image were in H-band (1.6 micron wavelength) the resolution of the 8.2 meter telescope is ~49 milliarcsecond, putting this image just at the formal resolution limit. Still, quite impressive stuff.

SiempreViernes 7y ago
Man, I don't know how to feel about this information: resolved imaging of stellar disks is from the 1880??! So from the list on wikipedia, I guess they could just do that one star, and didn't learn very much beyond the radius? What's the hottest results in the field of spatially resolved stellar observations?
- jconnop 7y ago
  The measurement was apparently made in 1920, not 1880s. Still surprising. https://en.wikipedia.org/wiki/Michelson_stellar_interferometer https://en.wikipedia.org/wiki/Michelson_stellar_interferomet...