ASTIGMATISM - IMPLEMENTATION
In the case of astigmatism, it will be quite simple. To implement it, we will use the GodRays Node and set the godrays 'center' to the center of the frame. For the tangential type, we shall use the 'rotate' slider, followed by a Transform Node with the 'rotate' value linked to the former and divided in half (i.e. by 2), as to remove any rotation offset. In the case of the sagittal type, we shall use the 'scale' slider, and this time there is no need to compensate with a Transform after. When the astigmatism does not coincide exactly with the x or y axis, use both sliders to find the pattern that suits you best.
