Night shots require a lot of patience and experimentation. Luckily with digital you can make mistakes but often with a really long exposure it will take your camera the length of the exposure to process the image so it’s good to have an idea of what your exposure should be. Again you need to weight down your tripod to reduce and camera shake. So that little hook thing that pulls out of the base of the neck of your tripod, hang your camera bag with the heaviest things you have (water bottles work well) and make sure to stabilize it so it doesn’t swing in the wind. To do an exposure longer than 30 seconds you need to set your camera on the B or Bulb setting. You can hold your finger on the shutter as long as you want but you’ll probably end up with some shake. That’s when you need this attachment to trigger the shutter and keep track of the time or use this camera remote again and keep track of the time elapsed on your smartphone. Best to attempt this on a very clear night without cloud cover.
Canon 5D Mark IV, Canon 24-70mm f/2.8 lens. ISO 200, f/8.0, 20 minute exposure.