Sentence:  Sketching galaxies and nebulae at the eyepiece, in low light levels, is no easy matter. A small torch can be used but that leaves one less hand free, so it's quite common to use a stiff plywood or plastic board to fasten the paper and light to – possibly with <WSD>bulldog clips</WSD> or clothes pegs. 
Meaning of the word marked with <WSD> tags:  A binder clip with rigid handles.