Finding power on some meridians

[Wlada]

Hello,
I want to find what power are in every 10 degrees of TABO schema of some lens.
I am using next formula to find powers in meridians: Fsph + Fcyl*sin^2(alpha).
For my purpose there is no need for more precision calculation. But, angle is problem. With this formula I get power in some meridian on some angle away from axis but no with respect of TABO shema. If some lens have power +0,42 Dsph = -0,84 Dcyl ax 127,05, what is power on 0, 10, 20... degrees but with respect of TABO schema. I am currently reading some article and I want to check numbers on pictures. Here is link:
http://www.oculist.net/downaton502/p...v1/v1c038.html
Thanks in advance
Wlada

[MakeOptics]

Hello,
I want to find what power are in every 10 degrees of TABO schema of some lens.
I am using next formula to find powers in meridians: Fsph + Fcyl*sin^2(alpha).
For my purpose there is no need for more precision calculation. But, angle is problem. With this formula I get power in some meridian on some angle away from axis but no with respect of TABO shema. If some lens have power +0,42 Dsph = -0,84 Dcyl ax 127,05, what is power on 0, 10, 20... degrees but with respect of TABO schema. I am currently reading some article and I want to check numbers on pictures. Here is link:
http://www.oculist.net/downaton502/p...v1/v1c038.html
Thanks in advance
Wlada

Use the difference of the angle you want from the axis as alpha. The sin formula will return the power in relation from the 180, if you want the vertical you can use cos which is the same as sin(axis -90) if you're wanting any other power you can sub in sin (axis - angle) we are essentially rotating the coordinate system and using the axis as our horizontal zero reference.

You must be working on something really fun.

[Wlada]

I got the same results what are in mentioned article with [{TABO axis} - {axis of cyl}]. In one meridian there is small difference, I do not know why, but everything else is ok. Picture 5. seems do not represent right case. Someone

You must be working on something really fun.

Yes, something about cross cyl technique, if this is fun ;)

[MakeOptics]

I got the same results what are in mentioned article with [{TABO axis} - {axis of cyl}]. In one meridian there is small difference, I do not know why, but everything else is ok. Picture 5. seems do not represent right case. Someone


Yes, something about cross cyl technique, if this is fun ;)

I am not exactly sure what you mean. Just so we are on the same page the term TABO notation has fallen out of favor decades ago it is now accepted as standard notation. The example of #5 in the link you gave is the addition of:

Plano +1.00 x 180
Plano -1.00 x 170

which sums to:

+0.17 -0.35 x 130

The formula's in the other thread produce these results. I have loaded the example in the spreadsheet which the formulas.

If you are looking for a method to find out which lens will neutralize the resultant power you can convert the resultant power into a dioptric power matrix and negate the torsional component, that will stop the corkscrew effect of the traveling rays, then all you need to do is neutralize the power with the same method by negating the value which will result in no power. That way if you were looking for the obliquely crossed power to neutralize any power or resultant power you can easily determine it.

[Wlada]

am not exactly sure what you mean.

I suppose that what you do not know for sure is what I mean with this: [{TABO axis} - {axis of cyl}]. This is the same what you said in previos post:

Use the difference of the angle you want from the axis as alpha. The sin formula will return the power in relation from the 180.

One lens is on 180 degree, and second on 170, with respect of TABO schema. Sum of this two cyl's are not problem. As you posted, the result is +0.17 -0.35 x 130. Problem for me was how to calculate what is the power of meridian of every 10 degree of this resultant lens, but with respect of TABO scheme. Thanks to you, with Fsph+Fcyl*sin^2({desire angle with respect of TABO schema}-130) I got the same results of power on meridians what are on picture in mentioned article.
So, again, thaks for help.

[MakeOptics]

I suppose that what you do not know for sure is what I mean with this: [{TABO axis} - {axis of cyl}]. This is the same what you said in previos post: One lens is on 180 degree, and second on 170, with respect of TABO schema. Sum of this two cyl's are not problem. As you posted, the result is +0.17 -0.35 x 130. Problem for me was how to calculate what is the power of meridian of every 10 degree of this resultant lens, but with respect of TABO scheme. Thanks to you, with Fsph+Fcyl*sin^2({desire angle with respect of TABO schema}-130) I got the same results of power on meridians what are on picture in mentioned article.
So, again, thaks for help.

Glad you got it to work out don't know how much help I was. When you are finished with whatever project you have going on I would love a peak.