Crossing, or turning off the A611 at the Coxmoor road junction heading towards Mansfield, the road crests a hill, and turns gently towards the right. Immediately after the corner, the road opens out into the picture below.
The entrance to the Observatory is on the right just before the white post in the image. A clearer view of the entrance can be seen in the lower two images on this page.
The entrance to the observatory is the highlit area in the image below. This area is expanded in the final image at the bottom of the page.
Sherwood Observatory Coxmoor Road Entrance