3/4 pink

[avruga]

I'll try again.

[avruga]

Apologies in advance as this is not everyone's cup of tea but here is my reasoning for applying a grid of thirds rather than quarters.




a is the angle between the incoming white and the line of the pot. For a 3/4 ball this is known to be 14.5 degrees, for 1/2 ball this is 30 degrees. I'll come back to this later.

The line from corner pocket to opposite middle runs through the centres of white and pink and is at 45 degrees to the side cushion.

x is what we want to find - how far along the cushion from the pink spot do we place the white to make a particular pot.

a + b = 45 deg.

Rather than work in mm it makes some sense to use a grid much like j6 has to keep the numbers simpler. A full size table is, according to wikipedia, 3569 mm x 1778 mm which for 52.5mm balls make it 68 balls x 34 balls to within a decimal place so the pink spot is almost exactly 17 balls from top and side cushions. So take y to be 17 (balls).

Still with me?

Since white and pink at contact are at 45 degrees and their centres are 1 ball diameter apart (a little trig) says y1 and x1, which are the offsets of the white centre from the pink are at 1/sqrt(2) which is 0.707.

x1 = y1 = 1/sqrt(2)

The triangle with angle b has sides y2 and x2 and you can say x2/y2 = tan(b) (again, just trigonometry).

Putting this all together to find x gives this...

x = x1 + x2.

we get x1 from above as

x1 = 1/sqrt(2), so now,

x = 1/sqrt(2) + x2.

but x2 = y2 tan(b), so

x = 1/sqrt(2) + y2 tan(b)

also, b = 45 - a, so

x = 1/sqrt(2) + y2 tan(45 - a).

y2 = y - y1 = 17 - (1/sqrt(2))

So finally,

x = 1/sqrt(2) + (17 - 1/sqrt(2)) tan (45 - a)

For any angle, a, we can work out how many balls along from the pink line to set up the shot.

Plug in a = 14.5 deg and you get x = 10.3 (balls). With 17 balls between pink and blue that puts it at 10.3/17 or 61% of the way towards the blue.

Plug in a = 30 deg and you get x = 5.1 (balls). Again, 5.1/17 is 30% of the way along the cushion.

So it isn't exactly the 1/3 and 2/3s that I estimated over the table and perhaps you could set this up by making it 2/3 of the way along the cushion and rolling it back one ball or half a ball. But I do believe it's closer than it is on the grid with quarters.

The shot I had a problem with was the 3/4 ball pink at half way between pink and blue on the cushion. Using this formula would make x = 8.5 balls and the potting angle comes out as 19.5 degrees which is thinner than a 3/4 ball.

[j6uk]

okay i get it.
this looks very promising

[markz]

Wouldn't it be easier for anyone trying these sort of 1/4,1/2 and 3/4 techniques out just to purchase Nic Barrows aim frame? At least you can consistently place the balls where they should be without the bit of guess work needed or carrying a protractor in your cue case.

[j6uk]

avruga, are you happy with my fraction graphics of the ob?
example 1/2

[j6uk]

I'll try again.

so by your calculations my 3/4 would be your inbetween 1/2 and 3/4 or 5/8 right?

[avruga]

Wouldn't it be easier for anyone trying these sort of 1/4,1/2 and 3/4 techniques out just to purchase Nic Barrows aim frame? At least you can consistently place the balls where they should be without the bit of guess work needed or carrying a protractor in your cue case.

It would and it should be more accurate. On the other hand a rule of thumb doesn't cost you 30 quid.

[avruga]

avruga, are you happy with my fraction graphics of the ob?
example 1/2

hi, j6.

Yeah, that seems perfect to me - the top of the white is directly above the outside edge of the pink.

[avruga]

so by your calculations my 3/4 would be your inbetween 1/2 and 3/4 or 5/8 right?

Yes, I made your 3/4 ball about 5/8 ths.

[tedisbill]

Apologies in advance as this is not everyone's cup of tea but here is my reasoning for applying a grid of thirds rather than quarters.




a is the angle between the incoming white and the line of the pot. For a 3/4 ball this is known to be 14.5 degrees, for 1/2 ball this is 30 degrees. I'll come back to this later.

The line from corner pocket to opposite middle runs through the centres of white and pink and is at 45 degrees to the side cushion.

x is what we want to find - how far along the cushion from the pink spot do we place the white to make a particular pot.

a + b = 45 deg.

Rather than work in mm it makes some sense to use a grid much like j6 has to keep the numbers simpler. A full size table is, according to wikipedia, 3569 mm x 1778 mm which for 52.5mm balls make it 68 balls x 34 balls to within a decimal place so the pink spot is almost exactly 17 balls from top and side cushions. So take y to be 17 (balls).

Still with me?

Since white and pink at contact are at 45 degrees and their centres are 1 ball diameter apart (a little trig) says y1 and x1, which are the offsets of the white centre from the pink are at 1/sqrt(2) which is 0.707.

x1 = y1 = 1/sqrt(2)

The triangle with angle b has sides y2 and x2 and you can say x2/y2 = tan(b) (again, just trigonometry).

Putting this all together to find x gives this...

x = x1 + x2.

we get x1 from above as

x1 = 1/sqrt(2), so now,

x = 1/sqrt(2) + x2.

but x2 = y2 tan(b), so

x = 1/sqrt(2) + y2 tan(b)

also, b = 45 - a, so

x = 1/sqrt(2) + y2 tan(45 - a).

y2 = y - y1 = 17 - (1/sqrt(2))

So finally,

x = 1/sqrt(2) + (17 - 1/sqrt(2)) tan (45 - a)

For any angle, a, we can work out how many balls along from the pink line to set up the shot.

Plug in a = 14.5 deg and you get x = 10.3 (balls). With 17 balls between pink and blue that puts it at 10.3/17 or 61% of the way towards the blue.

Plug in a = 30 deg and you get x = 5.1 (balls). Again, 5.1/17 is 30% of the way along the cushion.

So it isn't exactly the 1/3 and 2/3s that I estimated over the table and perhaps you could set this up by making it 2/3 of the way along the cushion and rolling it back one ball or half a ball. But I do believe it's closer than it is on the grid with quarters.

The shot I had a problem with was the 3/4 ball pink at half way between pink and blue on the cushion. Using this formula would make x = 8.5 balls and the potting angle comes out as 19.5 degrees which is thinner than a 3/4 ball.

This is my new favourite post of all time on TSF.

[Leo]

This is my new favourite post of all time on TSF.

You've took the words right from me Ted. It's a classic no question about it.

[j6uk]

Yes, I made your 3/4 ball about 5/8 ths.

i dont see it being possible, if we look again at the original shot and my 5/8 graphic, the pink wouldnt make the near jaw

[markz]

It would and it should be more accurate. On the other hand a rule of thumb doesn't cost you 30 quid.

I think the aim frame is £24.95 and checking on Nics site it's sold out and awaiting re print. I'd rather practice the point of contact than having the fractions in my head as I'm trying to focus on the shot. Anyone that's getting confused with the maths in this thread you should have a read of this, it's pretty basic but useful.

http://snookerdelight.com/snooker-ar...es-in-snooker/

[throtts]

Apologies in advance as this is not everyone's cup of tea but here is my reasoning for applying a grid of thirds rather than quarters.




a is the angle between the incoming white and the line of the pot. For a 3/4 ball this is known to be 14.5 degrees, for 1/2 ball this is 30 degrees. I'll come back to this later.

The line from corner pocket to opposite middle runs through the centres of white and pink and is at 45 degrees to the side cushion.

x is what we want to find - how far along the cushion from the pink spot do we place the white to make a particular pot.

a + b = 45 deg.

Rather than work in mm it makes some sense to use a grid much like j6 has to keep the numbers simpler. A full size table is, according to wikipedia, 3569 mm x 1778 mm which for 52.5mm balls make it 68 balls x 34 balls to within a decimal place so the pink spot is almost exactly 17 balls from top and side cushions. So take y to be 17 (balls).

Still with me?

Since white and pink at contact are at 45 degrees and their centres are 1 ball diameter apart (a little trig) says y1 and x1, which are the offsets of the white centre from the pink are at 1/sqrt(2) which is 0.707.

x1 = y1 = 1/sqrt(2)

The triangle with angle b has sides y2 and x2 and you can say x2/y2 = tan(b) (again, just trigonometry).

Putting this all together to find x gives this...

x = x1 + x2.

we get x1 from above as

x1 = 1/sqrt(2), so now,

x = 1/sqrt(2) + x2.

but x2 = y2 tan(b), so

x = 1/sqrt(2) + y2 tan(b)

also, b = 45 - a, so

x = 1/sqrt(2) + y2 tan(45 - a).

y2 = y - y1 = 17 - (1/sqrt(2))

So finally,

x = 1/sqrt(2) + (17 - 1/sqrt(2)) tan (45 - a)

For any angle, a, we can work out how many balls along from the pink line to set up the shot.

Plug in a = 14.5 deg and you get x = 10.3 (balls). With 17 balls between pink and blue that puts it at 10.3/17 or 61% of the way towards the blue.

Plug in a = 30 deg and you get x = 5.1 (balls). Again, 5.1/17 is 30% of the way along the cushion.

So it isn't exactly the 1/3 and 2/3s that I estimated over the table and perhaps you could set this up by making it 2/3 of the way along the cushion and rolling it back one ball or half a ball. But I do believe it's closer than it is on the grid with quarters.

The shot I had a problem with was the 3/4 ball pink at half way between pink and blue on the cushion. Using this formula would make x = 8.5 balls and the potting angle comes out as 19.5 degrees which is thinner than a 3/4 ball.

To all Snooker beginners ,
""Welcome"", and happy learning..
Hahaha.

Just pot the balls guys, forget the math and physics. See and shoot.

[j6uk]

I think the aim frame is £24.95 and checking on Nics site it's sold out and awaiting re print. I'd rather practice the point of contact than having the fractions in my head as I'm trying to focus on the shot. Anyone that's getting confused with the maths in this thread you should have a read of this, it's pretty basic but useful.

http://snookerdelight.com/snooker-ar...es-in-snooker/

that black he was struggling with was 1/2 ball. good players who know there 3/4 and 1/2 ball blacks off the spot hardly ever miss them