For the observation of the sun in the red spectral line of Hydrogen H a we use a Telescope with a very narrow Lyotfilter (0,07 nm FWHM), which must be precise temperature-controlled.
(a we; use; a Telescope) (a very narrow Lyotfilter; must be; precise temperature-controlled)
a we a very narrow Lyotfilter
use must be
a Telescope
precise temperature-controlled