Here is a velocity analysis of a solar prominence in CaH light -http://www.pbase.com/p_zetner/image/157098046 - presented as a set of Dopplergrams, with blue showing approaching plasma and red showing receding plasma at the speeds indicated. Each Dopplergram is produced by subtracting an image constructed at a given blue shift (from line centre) from the image constructed at the corresponding red shift and colourizing. For the Ca H line, a wavelength shift of 0.056 A corresponds to a line-of-sight velocity of 4.23 km/s. It's interesting to see that there are regions of receding plasma very close (in line-of-sight) to regions of approaching plasma, possibly indicating a twisting motion?
