Using Gann Angles to interpret price corrections is superior to Fibonacci retracements levels and or Fibonacci fans for the simple reason Gann Angles measure both time and price.
When price rises it is normally a slow grind upwards, however when price falls its very fast. Very much like a fishing rod. Price action suffers a slow grind up the rod until it begins to bend, and then a sudden and rapid decent along the fishing line. The collapse of price can actually be used to your advantage, as it must climb back up into the main trend channel and this is where you jump in. (see below).
When price collapses, many will say 'who will catch the falling knife', because those that try might lose their fingers. Let the large accounts (Wyckoff Composite man or Mr Market) catch rapid falling prices, let them form a base of (re) accumulation. You should a let little time pass before you enter the price pattern that you think will be correction within a long term upward trend. The use of Gann Angles during the price correction phase is an excellent tool for determining the correct time to enter the (re) accumulation phase before the trend continues.
See the chart for examples...
