My son is in the US Navy. He wants me to figure out which compact camera would allow him to take pictures at night while at sea of the stars, and bio-luminescence. Unfortunately, while he can use a tripod the ship will still be moving. After a lot of research I still don't know if it is better that he just get a point and shoot that does 4k video? Or is it possible for a novice to still get a fairly good picture? If you have any camera recommendations that would be awesome! Needs to be small enough to stow in tight quarters. Thanks!
Your intuition is correct. The tripod will not help much since there will be movement, so you cannot use slow shutter-speed. That means that he will have to resort to high-ISO and a large aperture. The larger the sensor in the camera, the better the results will be. Small sensor cameras have too much noise to discern stars when shooting at high ISO. For this reason, something like a Sony RX1R II would be one of the better choices. It is relatively compact and weighs about a pound (including the lens obviously), a Fuji X100F is only a tiny bit lighter. While limited in availability, he can probably use a Ricoh GR II but it does not quite match the quality of the others, although it weighs half as much.
in this case you might try "Gimbal" with tripod to reduce some amount of motion blur.