So I have a shot in mind that is both photographically technical and... well just technical aspects to it so I'm looking for a little help before I undertake it. I've added a pic below to help explain what I'm going for. The basic gist of the pic is as follows. I want to shoot the pic at night with the peak noticeable and the path of stars (long exposure) arching across the peak. In the foreground much like the white rock in the pic below is a natural rock arch which I want to highlight. Its located in a canyon not far out of town so there will be some ambient light. First off I've never done a long exposure of stars but I'm assuming you go with a tripod and low ISO (any practice suggestions are welcome). Two aspects I'm a bit unsure of are 1. should I use some sort of flash to highlight the arch (it will be about 100meters away) at the beginning or end of the exposure and 2. I want to shoot it with a bit of snow on the peak and I'm afraid it may overexpose the peak with the long exposure if there is too much light from stars, moon etc. Any suggested reading on the subject would be appreciated. A last complication is that I will have to rappel at night and sit suspended with some kind of rig for the tripod while doing this so I'm not going to be terribly comfy so I can't sit all night trying to get this shot right. This is a bit over my head in the photography aspect so I'm sure gaps in my post are evident. Thanks.