Astrophotographers uses long exposures. Another way is to shoot many shorter exposure photographs and stacking them. I saw one example and it was real.
I want to ask , is it applicable for panoramic shots. Do this technique increase the lp/mm count , how much increase per film frame ?
It's a digital technique called stitching. If you can manage an analogue stitch you would indeed have more line pairs per mm of the print because you would need less enlargement. I don't think you'll find analogue stitching easy or very successful.