What was the first method used to observe solar prominences without an eclipse?
I understand that Helium was first discovered in the Sun, separately by Pierre Janssen and Norman Lockyer, in 1868, discovering its spectral line at 588 nm and concluding that it might be from an unknown element.
They both used the solar eclipse of that year, I think, to observe the spectral line in a solar prominence, but both also later devised a method to observe solar prominences without an eclipse. Reference for Pierre Jannsen and reference for Norman Lockyer.
Currently, filters are recommended to observe solar prominences outside of an eclipse, was this the method that Lockyer and Janssen also used?
I looked up the original publication by Lockyer, but it does not mention if that observation was made during an eclipse.