90/90..mikjari asking

L

LAMas

AzB Silver Member
Silver Member
90/90 aiming - Today, 01:32 PM

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Has anybody tried to use the 90/90 aiming method? I find it a little less work to begin with to get to your pre-pivot point. After a week or two it's not a bad extra tool in my box. I'm at the point where I might be doing it well enough to trust it and turn off the feel on some of the tougher shots.
 
This deserves it's own thread.
I like double the distance except when you are on a cut greater than 30 degrees for you have to aim off of the surface of the OB.

WIth 90/90 you aim a part of the CB to a corresponding portion of the OB - aiming is never off of the OB as with double the distance.
For 90/90 you need to shift over to the center ball on the CB if you don't want to shoot with English. Then there are the perception problems in addition to parallel shifting problems.
 
I have a good 90/90 post on my blog. I had a perception prob with 90/90 prior to figuring out that my eyes should be on the opposite side of the CTEL. Once you get to 90/half and 90/reverse-90, your eyes move to the same side of the CTEL as your cue.
 
SpiderWebComm said:
I have a good 90/90 post on my blog. I had a perception prob with 90/90 prior to figuring out that my eyes should be on the opposite side of the CTEL. Once you get to 90/half and 90/reverse-90, your eyes move to the same side of the CTEL as your cue.
Click to expand...

I read your blog to get the 90/half and 90/reverse, but I find if I shorten my bridge I can use the same pivot with them. It feels like about 1/2 of my normal bridge. I usually do this when the OB is 2 or less diamonds from the CB.
When the pivot is right the balls start falling off the table. You have to work though to know which part of the OB is correct to hit. This is one area where "feel" takes over. The bridge length is another and of course the feel of the correct pivot. Once these are aligned you can really make some tough shots without looking at the angle or pocket. By not looking at the pocket I am referring to using it to aim at as you are down on the shot.
Tnx LAMas for the bump.
 
i have relearned from the CTE thread about using the parallel offset, I find that this (shift) will compensate for bridge distance and make pivoting not necessary.

As has been said before, in order to make the same shot, your cue stroke must contact the CB and send it to the OB the same - identity.

What I found with 90/90 is that by aligning perfectly with the cue at the correct 90/90 aim, the parallel offset to center CB effectively give you the same solution as double the distance.

As I said before, the advantage of 90/90 is for shots greater than 30 degrees, you are initially aiming at points on the CB and the corresponding point on the OB, befor the shift - in double the distance, you have to aim off of the edge of the OB to some point on the rail or cloth.

I you can aim off of the edge of the OB using double the distance, then you take away the variables of the parallel shift.
 
So you use CTE for the thick shots and 90/90 for the shots 30 degrees or more? I will have to work on the CTE instead of shortening the bridge. It's pretty accurate on shots where the CB and OB are close together, though.
 
Mikjary said:
So you use CTE for the thick shots and 90/90 for the shots 30 degrees or more? I will have to work on the CTE instead of shortening the bridge. It's pretty accurate on shots where the CB and OB are close together, though.
Click to expand...

I don't use CTE. I use double the distance, but I find that for cuts over 30 degrees that aiming off of the surface of the OB is kinda vague so 90/90 is helpful for the initial points of aim are never off of the OB.

I find that for shots where the CB and OB are close, that 90/90 is better than double the distance.

Again from dr_dave's site:

Per the diagram below, Don's system recommends sighting through the center of the CB (and not along parallel lines, as implied by traditional double-the-distance and contact-point-at-center-of-ball-overlap methods). Because of this, the system doesn't work well when the CB is close to the OB (see error "E" in the diagram below), but it works fine when the balls are farther apart, for all cut angles. See the document for more info and examples.


http://billiards.colostate.edu/threa...ng.html#double
 
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LAMas said:
i have relearned from the CTE thread about using the parallel offset, I find that this (shift) will compensate for bridge distance and make pivoting not necessary.

As has been said before, in order to make the same shot, your cue stroke must contact the CB and send it to the OB the same - identity.

What I found with 90/90 is that by aligning perfectly with the cue at the correct 90/90 aim, the parallel offset to center CB effectively give you the same solution as double the distance.

As I said before, the advantage of 90/90 is for shots greater than 30 degrees, you are initially aiming at points on the CB and the corresponding point on the OB, befor the shift - in double the distance, you have to aim off of the edge of the OB to some point on the rail or cloth.

I you can aim off of the edge of the OB using double the distance, then you take away the variables of the parallel shift.
Click to expand...

I misunderstood you when you said you relearned from the CTE thread the parallel offset. I assumed you meant the CTE offset. I've also used the double the distance and ghostball, but on long shots they do get pretty iffy, especially on thinner cuts. A 1/4 ball hit nine feet away always comes up on the eight, nine or ten ball!:wink:
Another odd shot is the almost straight in where you have to cut it just a degree or two, but it looks straight in. 90/90 stops these pocket rattles and allows you to cheat the pockets fairly well because you are lined up dead into the opening.
 
"The bridge length is another and of course the feel of the correct pivot. "
Mikjary

I also was pivoting when using 90/90, but when I analized CTE, I read where there was a parallel offset to establish a new bridge location before the CTE pivot.

When I studied the diagram and in AutoCad, I realized that 90/90 really wanted a parallel shift (not a pivot which adds a few angular degrees) back to the center of the CB to work for all distances between the CB and OB.
Thanks.
 
LAMas said:
"The bridge length is another and of course the feel of the correct pivot. "
Mikjary

I also was pivoting when using 90/90, but when I analized CTE, I read where there was a parallel offset to establish a new bridge location before the CTE pivot.

When I studied the diagram and in AutoCad, I realized that 90/90 really wanted a parallel shift (not a pivot which adds a few angular degrees) back to the center of the CB to work for all distances between the CB and OB.
Thanks.
Click to expand...

If you parallel shift, you'll always hit the OB square with no cut. That can't be right.
 
SpiderWebComm said:
If you parallel shift, you'll always hit the OB square with no cut. That can't be right.
Click to expand...

You are correct.
When I stopped using the pivot in the 90/90 method I morphed it into the contact poin to contact point parallel shift method.

"contact-point-to-contact-point or parallel-lines system

How does the "contact-point-to-contact-point" or "parallel-lines" aiming system work?

from jsp:

The first step is to draw a line going from the center of the intended pocket to the center of the object ball (purple dashed line). Extending this line to the opposite edge of the object ball gives you the object ball contact point (blue dot). To find the contact point of the cue ball, you simply just reflect ... as shown in the upper right portion of the figure.

Once you have the location of the cue ball CP, the next step is the draw a line through the object ball CP and the cue ball CP (green line). Then, you just simply imagine the line parallel to that line that goes through the center of the cue ball (orange line). This new line is what should direct your aim, since geometry tells you that this line connects the centers of both the cue ball and ghost ball. To make the shot, you just stroke through this line (black arrow)..."



jsp_parallel_contact.jpg
 
I understand what you're saying, but you're defeating the point with 90/90. Why even worry about CPs? Just 90/90 and hip pivot the ball in. I don't know where the contact point is and I don't care really. The pivot is what makes the ball. :)
 
Jal said:
:)

Thanks for not getting angry at my little joke.

Jim
Click to expand...

Too many times posters get caught up in the moment and don't realize that there are real people out there behind their avatars. If somebody injects some humor it makes things all that much better! :hug: Group hug.
 
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