Accurate positioning of image on background

[james adamson]

I have made a kind of Milky Way image and am trying to control where it sits on the background sphere.
The image is an 8k latlong. I have imported it into an image shader and set spherical projection. I assume the size control works as 1 equals full size?
I have then connected a transform input between the image map and the default shader which is the output of the chain. The default shader does nothing other than control luminosity. I have no projection parameters set within this shader.
I am moving the image around on the sphere by adjusting w and y rotation values in the transform input but am finding it difficult to set an exact position.
Ideally I would like repeat x and y off as I am superimposing this on top of another image map of a starfield using a merge shaders node.
So I just want to know how to directly position my milky way image on the sphere. Am I over complicating this?? Probably.

[james adamson]

W rot?? I meant x.

[Matt]

I would use a camera projection. It can be a separate camera. Then it becomes more straightforward to change the projection by rotating the camera and changing its field of view.

[WAS]

Additionally a image at 0,0,0 is, well, at 0,0,0, so you can rotate explicitly accurately along the background sphere. But that's maths. I'd use a camera and point it too in a pinch.

[james adamson]

Yep. I was over complicating it. Thanks guys.