Using light reflection for aiming

[eezbank]

Yes, that's the way I do it too. But it's important not to shift exactly parallel - the amount you shift the tip of the cue (at the opposite rail) must be 1/2 the amount you shift the butt (at the bottom rail).

Here's the same shot, but moved over a little to make this more visible:

CueTable Help

The red line is the "track line" from the 2nd diamond on the near rail to the 1st diamond on the far rail. Shifting "parallel" to that track line actually means shifting the tip of the cue 1/4 diamond to the left (to 1-1/4 diamond) and the butt of the cue 1/2 diamond to the left (to 2-1/2 diamonds). If you actually shifted the cue parallel with the track line, you'd be aiming from 2-1/2 diamonds to 1-1/2 diamonds, and you'd miss the bank by a half diamond.

[NOTE: These measurements are taken at the "gutter" (where a rail-frozen ball touches the table surface), not at the diamonds themselves.]

pj
chgo

if you divide the bottom rail into half diamonds and the top into quarters you only shift a very small amount.

 

[Patrick Johnson]

if you divide the bottom rail into half diamonds and the top into quarters you only shift a very small amount.

You're right that if you're shifting a very small amount from a track then it's less important to shift the top less than the bottom. If 1/2-diamond and 1/4-diamond tracks is too many to visualize, another way to make the visualization easier is to visualize two tracks for each shot, one on either side of the ball - then it's easier to see how the aiming line should "parallel" the tracks.

Here's a graphic that shows banking tracks for banks to the bottom left corner using all the diamonds along the bottom rail (and half of them on the top rail, of course).



Each white object ball is between two of the tracks, and visualizing both tracks makes it easier to see how the ball's banking line should fall between them: more parallel to the track it's closest to or evenly dividing them if it's about centered between them. Each two tracks forms what I call a "banking lane" between them.

pj
chgo

 

[Bob Jewett]

... Each white object ball is between two of the tracks, and visualizing both tracks makes it easier to see how the ball's banking line should fall between them: more parallel to the track it's closest to or evenly dividing them if it's about centered between them. Each two tracks forms what I call a "banking lane" between them. ...

Maybe it's been pointed out above, but it bears repeating: For the perfect mirror system you're illustrating, the tracks do not pass through the diamonds. For the systems that do have the tracks passing through the diamonds, the drawn tracks will be "shorter" (more parallel to the short rail) than the perfect mirror tracks.

 

[Patrick Johnson]

Maybe it's been pointed out above, but it bears repeating: For the perfect mirror system you're illustrating, the tracks do not pass through the diamonds. For the systems that do have the tracks passing through the diamonds, the drawn tracks will be "shorter" (more parallel to the short rail) than the perfect mirror tracks.

The graphic (which you may not be able to see) shows the tracks going from gutter to gutter in front of each diamond, but it's worth saying it anyway.

However, using the diamonds themselves is one way to estimate a rough correction for some of the wider-angle banks (that usually go long because natural roll on the OB dominates over rail friction).

pj
chgo

 

[androd]

The graphic (which you may not be able to see) shows the tracks going from gutter to gutter in front of each diamond, but it's worth saying it anyway.

However, using the diamonds themselves is one way to estimate a rough correction for some of the wider-angle banks (that usually go long because natural roll on the OB dominates over rail friction).

pj
chgo

really interesting info. thanks to the guys that took the time to post the visuals, Patrick Johnson, eezbank, dave, neil and others. it's one of the great things about this site,
a shame everyone won't read these posts,