NavList:

Do you have this image in a higher-quality format?  I'd be happy to have a go at it with the plate-solver tools (SCAMP from astromatic.net, which is free and open-source).  It will jointly estimate the lens distortion along with position and orientation.

I could try with the existing image, but the stars are a bit undersampled---higher resolution would probably improve them.  Also JPEG is not exactly helping.

Incidentally, I wonder if this image is a composite.  The stars are not trailed, so I imagine the camera was on a tracking mount, unless the exposure was very short.  But the background is also sharp---it might have been taken separately and composited in.  Shouldn't matter for the latitude computation, I guess, provided the camera orientation was kept exactly the same for the two exposures.