Kulashaker

Hi Just signed up here so please bear with me.... I've been trying to stack some night images to make a star trail image. Is there a limit to how many images that can be put together? Affinity Photo always seems to give up the ghost. Ive been trying to put together 100 images. Then 50. And nothing. Although it says its loading a document, it never does. Unless its going to take hours and I'm not patient enough? Thanks K