by Hap Rocketto
There is a lot of range talk about mirage. We are all familiar with the cartoon view of it: Bugs Bunny, wearing a French Foreign Legion Kepi, crawling across the desert towards a glass of water that will disappear. There are times when the mirage does just that to a good string! Mirage is nothing more than the refraction, or bending of light waves, caused by the differing density of warm and cool air. This causes an optical effect that causes us to see wave-like ripples through our scopes. These waves are a double-edged sword in that they can cause sighting errors that will cut a good string into pieces or protect us by giving good indications of wind.
There is actually a displacement of the apparent location of the bull by the mirage. This placement causes the shooter to aim in the direction the mirage is moving, and away from the center. It is important to be sighted in for the mirage and to be prepared to make corrections when it shifts. Mirage is moved by the wind and is therefore an excellent wind gauge. The best way to “read” the mirage is to focus your spotting scope at some distance between you and the target so that both the shot holes and mirage may be seen. This is no mean feat and will take some trial and error to find what works best for you. When doing this the shot holes or the target have to be sharply in focus.
Once this is done, observe the mirage to get an idea of its general flow and patterns. On a practice day shoot through the mirage and get an idea of its effects the strike of the bullet. This type of practice will begin to give you the experience required to make changes in a match. The mirage itself is difficult to deal with but the information it gives you as to wind is invaluable. When you go to the scope to check the value of a shot make a quick check of the mirage. If it is the same as it was prior to releasing the shot then you may rely on your call. If it is different than that may help you account for a shot that is-off call.
Of course there are always days when it is switching so fast that is almost impossible to keep up with the switches. There is very little you can do when conditions are fast and variable. You have to rely on your experience and be confident. In any case remember that the conditions effect all, just keep your wits about you.
