How to create a curved color spectrum?

I'm trying to create a curved "spectrum" of color to use behind the numbers on a gauge.

I first tried a linear fill, going from green to red. It's easy, but it doesn't produce the yellow in the color transition.

Next, I tried placing swatches of colors and then using the arch as a mask ... but it would only pick up the solid colors, so there were no transitions.

Does anyone know of a method that might work? Is there a way to bend the staight color spectrum bitmap shown in the graphic?

Thanks in advance for any help.

Hi Contours,

Draw your arc as a single shape and then use a conical fill from red to green and set the fill effect to "Rainbow" to make it transition through yellow.

Phil

if you want more control you can add more handles to the fill line curve

you could also use a blend to a blend [to a blend... the more blends the more colour control] - and then fit blend to curve - but Phil's way is simpler :)

Thanks for the suggestions. I was able to get exactly the result I was after by using 3-color Simple. Here's a snapshot for anyone who might find this thread.

I appreciate your help.