An alternative quick way in Photoshop is to go to the crop tool - in the options bar set it to Golden ratio
You may need to move the crop handles to make the grid appear - no worries just wiggle them and put them back to the original position (you are not going to crop)
Then drag a guide from the ruler over the golden ratio crop grid
You can now leave the crop tool without cropping - but the guidelines will be in the ratio you require.
2 problems though:
1 - It draws the spiral upside down and I cannot find a way to flip it
2 - It draws the spiral out of proportion.
See attached screenshot
Use Shift+O to cycle the orientation of the overlay and the direction of the spiral - so there are 8 variations to cycle through (4 of which are correctly drawn)
Trevor, why is it that when I am scrolling through various threads the ones that make me bust out laughing are almost always yours? This is hysterical!
Thanks Dave - superb stuff.