a climb. There are several techniques and variations to  centering. One method involves paying close attention to  where the thermal is strongest; for instance, toward the  northeast or toward some feature on the ground. To help  judge this, note what is under the high wing when in the best  lift. On the next turn, adjust the circle by either straightening  or shallowing the turn toward the stronger lift. Anticipate  things and begin rolling out about 30° before actually heading  toward the strongest part. This allows rolling back toward  the strongest part of the thermal rather than flying through  the strongest lift and again turning away from the thermal  center. Gusts within the thermal can cause airspeed indicator  variations; therefore, avoid “chasing the airspeed indicator.”  Paying attention to the nose attitude helps pilots keep their  focus outside the cockpit. How long a glider remains shallow  or straight depends on the size of the thermal.  [Figure 10-10] Other variations include the following:  [Figure 10-11] 3.  Straighten or shallow the turn for a few seconds when  the stronger seat-of-the-pants surge is felt. Then,  resume the original bank. Verify with the variometer  trend (needle or audio). 1.  Shallow the turn slightly (consider 5° or 10°) when  encountering the weaker lift, then as stronger lift is  encountered again (feel the positive G, variometer  swings up, audio variometer starts to beep) resume the  original bank angle. If shallowing the turn too much,  it is possible to fly completely away from the lift. 2.  Straighten or shallow the turn for a few seconds 60°  after encountering the weakest lifts or worst sink  indicated by the variometer. This allows for the lag in  the variometer since the actual worst sink occurred a  couple of seconds earlier than indicated. Resume the  original bank angle. Figure 10-10.  Centering by shifting the circle turn toward stronger lift. Figure 10-11.  Other centering corrections. 10-8 Lake Shift circle toward lake Lift strongest when high wing points toward lake 1 3 2 Surge of lift felt here Lowest variometer indication wait 60° Do not shallow too much Shallow, then steepen Lowest variometer indication