Historic camera found in NLO store room

Can anyone expalin the resaon behind the design of this camera? It is a beautifully made hardwood (mahogany) plate camera with precision brass fittings.
The focal plane of the camera is highly inclined and not perpendicular to the optical axis if it was attached to a telescope. There is a shutter mechanism which
allows different parts of the plate to be exposed. I realise that the blue and red end of the spectrum have different foci, but would not have thought it would be this extreme? But maybe with a long focus refractor that may be so?

David