Focusing the lens at exactly the hyperfocal distance is very difficult. Sometimes, it's not even necessary. Once you've calculated the hyperfocal distance, make sure you focus the lens at a distance that is a little bit longer (2-3ft - 0.5-1m) than the hyperfocal distance. If you focus at a shorter distance than the hyperfocal distance, even by an inch (2.5cm), the subjects at the horizon (e.g. stars) won't be in focus!
Once you've decided the focal length and aperture, focus the lens at the hyperfocal distance, always making sure that you're not falling short. It's better to focus a little bit further than the hyperfocal distance. This will ensure that everything at the horizon is in focus. Falling short will blur all the elements at the horizon (mountains, stars, etc.). 1e1e36bf2d