Outside of the north facing control room door is seen beneath the open arch.

Detailed view of the skirt system. Note the double layer of brushes used on both sides of the knee wall/skirt. This prevents dust, blowing snow and *possibly* insects/rodents from getting into the observatory/telescope area. The end wheel assembly with its double set of red wheels can be seen. One wheel physically touches the large, 6" diameter concave wheel that rides on the rail. The clear red wheel does not touch the rail however so it spins backwards in relation to the 6" wheel (shown charcoal black above). The smaller wheel that spins is connected to another small wheel that has brushes. This friction driven system keeps the most volunerable section of the rail, the very top/flattest surface, free from debris automatically.

 The brush wheel can more easily be seen but also note the angled piece that prevents the arch from being lifted up by gales, to the right and below the round rail, from viewer's perspective.