Hey, that's were we were ... well, almost. This group was in the astronomical complex on the next hill over from our location at Red Summit. I am sorry that their location was restricted; I should like to have met with some of the observers over there.
The article motivated me to look more carefully at my prominence-detail exposures around ingress and egress. Sure enough, several frames during ingress show a clear illumination arc which I presume to be the same phenomena as described in the S&T article.
The one below, taken at 17h20 GMT, just before second contact showed the best detail. Images were taken with a Lunt LS60T/PS Hydrogen-Alpha telescope with a DMK41 monochromatic video camera. Since I was primarily trying to get full-disk images, I was not using any additional optical magnification. The resolution is not great on these enlarged images but you should be able to see the arc. You may have to brighten your screen intensity to see it as the contrast is still pretty low.