Your field of view is mainly limited by the telescope’s focal length and your camera’s sensor size. At 1200mm, especially with an APS-C sensor, large objects like Orion will look quite tight in the frame.

Practical options:

• use a focal reducer: this shortens the effective focal length and widens the field of view. However, reducers are often telescope-specific, and compatibility with reflectors can be limited.
• make a mosaic: shoot multiple overlapping frames and stitch them later. This is a common astrophotography solution and works well if you’re already stacking exposures.
• piggyback a camera and lens: for large nebulae, a normal camera lens on top of the telescope can give a much wider field, though with less fine detail than prime focus through the scope.
• use a larger sensor: a full-frame camera gives a wider field than APS-C at the same focal length, though it may introduce issues like vignetting depending on the telescope.

So yes: for very large deep-sky targets, piggybacking or mosaics are often the most practical solutions; a focal reducer may help if one exists for your reflector.