F.W. Aston subsequently discovered different stable isotopes for numerous elements using a mass spectrograph.
From the en.wikipedia.org
The astronomers then used the UVES spectrograph on ESO's Very Large Telescope to record 20 spectra and so measure the period and the mass ratio.
From the sciencedaily.com
Then they used a sensitive spectrograph on a 3.6-meter telescope in Chile to measure its gravitational tug on the star, thus deriving the planet's mass.