Press on the
Shift button and choose simultaneously the
Ellipse Tool (U) to draw several more small circles.

The layer’s parameters:
Fill 0% on the layers.
Blending Options>Gradient Overlay
Gradient’s parameters:
Blending Options>Stroke

We shall use the earlier described method to draw several more circles, applying the
Ellipse Tool (U).

The layer’s parameters:
Fill 0% on the layers.
Blending Options>Gradient Overlay
Gradient’s parameters: