Is there a software tool to create a graphical fit to a set of data?

Sat, 11/05/2022 - 20:24

Hi, Assuming that I have a set of observational data (for example, the magnitutde of a star over time, or the light intensity of a star under different filters) and I would like to create a graphical curve for the data that also provides a mathematical expression description of the curve, what is the best software tool to do this?  Is it a tool that the AAVSO offers?  Or are there other, better software available to do this?  What would you recommend?  Thanks!