The ghost ball myth

[pdcue]

https://youtu.be/sMtMTD0P9-g
https://youtu.be/CGsXQ1MvO9Q
enjoy.

steven
66 views, no response.
be sure to check out the second video...

Will anybody ever get this right?

The Ghost Ball is one of many techniques for visualizing a target.

Visualizing is not aiming.

Visualizing, sighting, aiming. If you don't know the difference between these three,
you shouldn't be allowed to post about "aiming".

Of course then 98% of aiming threads wouldn't exist

Dale

 

[Jal]

Nic Barrow is showing increasing "impact throw" (collision- or cut-induced throw) as he moves from 3/4-ball hit (or aim) to 1/2-ball hit to 1/4-hit hit to 1/8-ball hit.

www.youtube.com/watch?v=CGsXQ1MvO9Q

Conventional wisdom is that CIT is at a maximum at roughly a half-ball hit.

What is going on here?

That's true for stun shots. In his test setup, however, the cueball can pick up topspin on the way to the object ball, even though the distance between them isn't very much. In the case where the cueball is at full natural roll upon contact, for instance, throw increases almost linearly with cut angle. Below is an excerpt from Dr. Dave's TP_A-14 showing throw versus cut angle for various degrees of topspin. The topmost (purple) is for stun, while the bottom one (red) is for full roll. The others are in-between.



Also, in the video you can see that the object ball isn't entering the same part of the pocket for all the shots. As the cuts get thinner, it enters progressively from right to the left as viewed from the camera behind the pocket. So as the cuts thin out, there's less throw than is apparent if you're simply judging from the fact that the ball is pocketed.

Jim

 

[Sloppy Pockets]

That's true for stun shots. In his test setup, however, the cueball can pick up topspin on the way to the object ball, even though the distance between them isn't very much. In the case where the cueball is at full natural roll upon contact, for instance, throw increases almost linearly with cut angle.

On the first (3/4 hit) cut he seemed to use less force and the CB didn't roll along the tangent line, so it must have picked up forward roll, but in the thinner cuts he seemed to slide the ball a lot harder and the CB followed the tangent line, indicating the OB was struck with a sliding CB.

 

[Jal]

On the first (3/4 hit) cut he seemed to use less force and the CB didn't roll along the tangent line, so it must have picked up forward roll, but in the thinner cuts he seemed to slide the ball a lot harder and the CB followed the tangent line, indicating the OB was struck with a sliding CB.

Good point. But I think it's hard to tell what exactly is happening without taking precise measurements off the video. You'd also have to determine how slick the cloth is (i.e., coefficient of friction) to determine just how quickly the CB is picking up topspin before the collision.

With the subsequent faster shots and the thinner cuts, the CB will tend to remain near the tangent line over a longer distance before noticeably curving forward. And we're not talking about the CB being in a full roll state either, which also "delays" the curving.

In other words, given the somewhat murky state of several variables, the video, imo, isn't cause for concern that the theory of throw and the results of previous tests are suspect.

Jim

 

[RichSchultz]

I think cloth age/slickness and ball age can also impact the slide...thereby altering the ghost ball path. Right?

 

[Patrick Johnson]

He doesn't understand how to use ghostball as well as others it appears.

Ghostball can be placed anywhere needed around the OB. It does not always have to be placed as for a center pocket shot and that is what is being assumed here and used here.

When I need to adjust for spin, have a different placement for the ghostball than when not adjusting for spin.

Ghostball is not a fixed point that is alway on the center pocket line, but it is movable to where needed.

The placement of the ghostball, in the minds eye, is not done until all variables are taken into account, then the spot on the table is picked to put the ghost ball contact patch.

duckie got it right this time. "Ghost ball" doesn't mean visualize the ghost ball strictly on the OB/pocket line; it means visualize it where it needs to be to make the shot. The whole premise of the video is mistaken.

pj <- same with "contact point" aiming
chgo

 

[Saturated Fats]

Maybe I missed it, but...

With all of the precision claimed in the making of the potting robot, I can't tell how the object ball precisely placed?

 

[ENGLISH!]

Was the table he used a directional cloth?

 

[Sloppy Pockets]

Good point. But I think it's hard to tell what exactly is happening without taking precise measurements off the video. You'd also have to determine how slick the cloth is (i.e., coefficient of friction) to determine just how quickly the CB is picking up topspin before the collision.

With the subsequent faster shots and the thinner cuts, the CB will tend to remain near the tangent line over a longer distance before noticeably curving forward. And we're not talking about the CB being in a full roll state either, which also "delays" the curving.

In other words, given the somewhat murky state of several variables, the video, imo, isn't cause for concern that the theory of throw and the results of previous tests are suspect.

Jim

I guess all we can assume is that there was no initial backspin on the ball, since the flat tip is contacting the CB exactly at the equator.

Another thing to consider is that none of the shots were made with what I'd call a typical crisp snooker potting speed, so throw would be even less in most real shooting situations. He should also use a training ball like a measles ball so we can see in slo-mo where and when the forward spin begins to take over.

Too bad the device isn't spring-loaded, as well as being adjustable and calibrated for various speeds. I've been toying with the idea of building a simple device like this one, except I would use a spring to propel "cues" (projectiles) of various weights, end masses, and tip sizes. I think such a device would come in handy for a lot of objective testing.

 

[michael4]

duckie got it right this time. "Ghost ball" doesn't mean visualize the ghost ball strictly on the OB/pocket line; it means visualize it where it needs to be to make the shot. The whole premise of the video is mistaken.

pj <- same with "contact point" aiming
chgo

I agree with you, but it looked like to me, that in the video he did adjust the line to where it needed to be to make the shot. (he adjusted the ghost ball to line up slightly outside the pocket)

 

[Jal]

I think cloth age/slickness and ball age can also impact the slide...thereby altering the ghost ball path. Right?

Not sure what you mean by "ghost ball path," but certainly surface conditions of the balls and cloth do affect most everything.

Jim

 

[Jal]

I guess all we can assume is that there was no initial backspin on the ball, since the flat tip is contacting the CB exactly at the equator.

I guess that much we can be fairly sure of.

...He should also use a training ball like a measles ball so we can see in slo-mo where and when the forward spin begins to take over.

My sentiments exactly. But then my explanation of acquired topspin on the way to the OB would be put to the test...never a good thing.

... I've been toying with the idea of building a simple device like this one, except I would use a spring to propel "cues" (projectiles) of various weights, end masses, and tip sizes. I think such a device would come in handy for a lot of objective testing.

I agree, except if you're one of the poor souls that follows the aiming threads, the word "objective" has a very malleable meaning around here.

Jim

 

[duckie]

CTE Sucks!!!!!!!!!

 

[Johnnyt]

I mean really. Do we have to have a "How to aim thread every week or so? Give it a rest. All you're doing is confusing new players. Johnnyt

 

[paaca]

So, does impact throw refer to what the cue makers, or some of them anyway, call deflection?

 

[3andstop]

So, does impact throw refer to what the cue makers, or some of them anyway, call deflection?

No, impact throw occurs between the CB and the OB. Deflection occurs between the CB and cue stick.

 

[Patrick Johnson]

FWIW, it's pretty clear from the CB's after-collision paths that all the shots were hit with a sliding CB (no forward or reverse rotation). This also means that (in order to slide a foot or so to the OB) they were hit above lag speed.

pj
chgo

View attachment 97538

 

[pdcue]

I mean really. Do we have to have a "How to aim thread every week or so? Give it a rest. All you're doing is confusing new players. Johnnyt

Amen Mr t... esp when they set up a separate but equal "Aiming Conversation" section.

Dale

 

[SplicedPoints]

For the longest time I thought my problem with aiming was knowing where to aim my tip on the object ball to make it.

I used some systems, i.e. ghost ball, drawing lines, and etc. Then one day I realized I know where to hit the ball 80% of the time instinctively, after all the years of playing. I simply cross checked where my instincts told me to hit versus the point the aiming systems told me to hit. Sometimes I need a bit more precision due to the difficulty of the shot, but for +80% of the shots, playing by "feel" is good enough.

Then I discovered all the misses isn't me not knowing where to hit on the ball. It is me not hitting where I thought I was aiming. In another word, simple fundamentals such as a straight stroke (which I thought I had) and proper body alignment are just as important to consistent potting as knowing where to aim.

Just my 2 cents.

 

[JB Cases]

Jim

It's all clear now.