Paul, you can also see the summit of Dome in this photo. It's right between Sentinel and Old Guard. The proof is in this photo taken from the summit of Dome.
Dead center in this photo are Sentinel and Old Guard, and between them is the little thumb of snow descending from the eastern notch of S-F Col. I only discovered this while examining my slides after the trips. Our PT trip was in '88, and the Dome summit photo was taken in '86.
looking bivy. Nice series of photos.