While looking through binoculars click on your unit symbol in the lower right area. Pick "Observe Here" then click on the unit/area in your bino view you want to observe. Go to the F5 (map) view and your unit should have a tactic applied that shows coverage arc with the view bubble on top of the unit/area you selected to observe.
Not an M1 tanker but I saw a conversation between one and other people asking this same question. Apparently the older setup induces less strain on the eyes when spending long times looking through the site, especially at night.