A must have tool when shooting the night sky is a remote release trigger for your camera. Triggers range from very simple cable releases over phone apps that connect to your camera’s Wifi to very specialized Intervalometers. I tried the phone apps for my cameras and they miss a very basic feature: bulb mode timing. Meaning, when you set the camera to bulb mode and start the exposure, most apps do not display how long the shutter is open already. It also eats battery life from the camera as Wifi or bluetooth needs to be on on the camera. In the mid range there are Intervalometers that can be programmed through a small display and some buttons and usually work quite well.