Can I start a gradient fill from a specific point?

[manylaughs]

I'd like to start a radial gradient fill for the center of my image. Is there a way to start the gradient from a specific point in the image? So if the image is 1000x1000, I'd like to position my pointer at 500,500 and move out from there.

I know I can see the point position in the info area, but my hand can slip a little and i might start at 504,498.

Thanks for any help