Re: CRT book by Keller
I actually have the same question as Roy.
There are "CRTs" that merely illuminate the entire face of the tube, and others that have some limited amount of control over the illumination (e.g. the 6E5 tuning eye, or DM160 "Magic-Eye" indicator tubes). It is not clear from the description that the "coketron" was able to scan the beam, or whether it merely caused the end of the tube to illuminate like these Russian ILD3-K tubes (https://www.ebay.com/itm/ILD3-K-P590-ULTRARARE-VINTAGE-CRT-VFD-INDICATOR-TUBE-for-DIY-and-education/112031678404).
My copy of Peter Keller's book has not arrived, so I am speaking from a certain depth of ignorance.
-- Jeff Dutky