BEST PHOTO-EDITING APP FOR BEGINNER ASTROPHOTOGRAPHERS
How do you calculate the correct shutter speed? We use the ‘500 rule’. In its simplest form, this is 500 divided by the focal length of the lens. If you’re using a 20mm lens, this would be 500/20, so 25 seconds. This only applies to full-frame cameras. For a crop-sensor camera, the crop factor needs to be taken into account, so in this instance we would recommend using a base value of 300 for your calculations. We recommend starting with an exposure of 20 seconds, which is about the longest you can leave the shutter open before stars begin to trail. See how that looks, then adjust.
Now all you have to do is compose the frame, take the shot and wait for the image to pop up on the LCD display. If your foreground is looking dark, try ‘light painting’ your subject with a headlamp or your smartphone light during the exposure to help brighten the scene. You may need to adjust the ISO or aperture slightly to find what works best for your location, but you are now firmly on your way to capturing your own images of the beautiful night sky.