Nikon Z7 and Astrophotography, versus Nikon D850
See my Sony mirrorless wishlist and Nikon mirrorless wishlist and Canon mirrorless wishlist.
Following noise evaluation for an outdoor scene, here are two pages evaluating noise with the Nikon Z7, witih one of them compared to the Nikon D850.
Nikon Z7: Astrophotography at ISO 180 Without Long Exposure Noise Reduction
Nikon Z7: Astrophotography vs Nikon D850 with/without Long Exposure Noise Reduction
Includes actual pixels crops and up to full resolution images.