To encourage Low Resolution (LR) registrations of the VV Cephei behavior a didactic presentation of such a spectrum is presented in the attachment. Anyone entering the campaign has a starting point this way.
A reference spectrum of a M2 I type star is superimposed.
Here we can see in the spectral range 5000 – 7000 Å the following spectral lines typical for M2 I stars: Magnesium triplet, Sodium doublet , Fe I lines, Blend with Fe I, Ba I and sporadic Ti.
The Hydrogen alpha line is in absorption on the reference. In contrast to this the Hydrogen alpha line on the recorded spectrum is in emission due to the mass transfer effect – accretion around the B type star. (White line on the recorded spectral strip)