The Keck telescope's High Resolution Spectrograph (HIRES) has previously provided evidence for a smaller fine-structure constant, {alpha}, compared to the current laboratory value, in a sample of 143 quasar absorption systems: {Delta}{alpha}/{alpha}=(-0.57+/-0.11)10^-5^. The analysis was based on a variety of metal-ion transitions which, if alpha varies, experience different relative velocity shifts. This result is yet to be robustly contradicted, or confirmed, by measurements on other telescopes and spectrographs; it remains crucial to do so.

Cone search capability for table J/other/MmSAI/80.833/table1 (Values of {Delta}({alpha})/{alpha} and corrections for possible intra-order distortions of the wavelength scale)