Because pockets are bigger than the balls we shoot into them, our target on the OB is not a pinpoint but a small arc of the equator - the OB contact point is really the OB contact area - its size is the margin of error for that shot.
We hear the terms OB contact area and margin of error frequently on AzB, but what do they mean? How small are these contact areas - can they be seen by the naked eye? Does it matter?
I don't know if it matters, but I know a quick way to visualize how big the OB contact area is for any shot:
To visualize the OB contact area for the spot shot pictured below:
- Imagine the OB centered where it is but enlarged until its equator touches the pocket (the big hazy white disc below).
- Visualize the size of the small segment of the enlarged equator that's between the pocket points.
- Now imagine that enlarged OB is really the normal size OB on the spot and you've just zoomed in to get a close look at the size of the contact area - in fact that's exactly what you've done. The contact area's actual size is that same small fraction of a normal size OB.
pj
chgo

We hear the terms OB contact area and margin of error frequently on AzB, but what do they mean? How small are these contact areas - can they be seen by the naked eye? Does it matter?
I don't know if it matters, but I know a quick way to visualize how big the OB contact area is for any shot:
To visualize the OB contact area for the spot shot pictured below:
- Imagine the OB centered where it is but enlarged until its equator touches the pocket (the big hazy white disc below).
- Visualize the size of the small segment of the enlarged equator that's between the pocket points.
- Now imagine that enlarged OB is really the normal size OB on the spot and you've just zoomed in to get a close look at the size of the contact area - in fact that's exactly what you've done. The contact area's actual size is that same small fraction of a normal size OB.
pj
chgo

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