Launched in 1990, the NASA/ESA Hubble Space Telescope remains the premier UV and visible light telescope in orbit. With well over 1.6 million observations from 10 different scientific instruments, the ESA Hubble Science Archive is a treasure trove of astronomical data to be exploited.
European Space Agency, ODell comma Charles Robert, 2007, 'Determining the Lifetime of Planetary Nebula Knots from Observations of the Core of the Helix Nebula.', 1.0, European Space Agency, https://doi.org/10.5270/esa-yncwmx7