Measure Cyl correctly without test lens kit?

I measure my astigmatism using DIY tools and the results sometimes change. My spur blur is at 23 cm while my cyl blur often changes sometimes 16 cm, 14 cm, 8 cm. if I force close my eyes a few seconds and then open it, the directional blur gets worse. I don’t have a test lens kit. so can I know my cyl correction without having to use a test lens kit?

Welcome to the forum, Stevan.

That ranges from -2 to about -6 of cylinder, so that is indeed not very useful. Your spherical measurement puts you at -4.25, and your cylinder is highly unlikely to be more than your spherical.
Do you not know what the cylinder is in your current pair of glasses?
It seems as if you will either have to invest in a test lens kit, with its own challenges, or a visit to an optometrist, who will measure your current glasses, as well as your current vision.
Good luck on this journey.

You can do a corneal topography and get those refractive analysis values. It may create overprescription if you choose them but I recommend them if you are tired of blur adaptation and you think you tolerate ‘perfect’ vision. This is my result for example:

Do you have a baseline astigmatism angle to start with our are you starting from scratch?

I hesitate to recommend the stenopaeic slit, because we have another thread going where it seems to be completely misunderstood, but in theory it could be used with distance to blur measurement.