他们搜寻的时候，是先对同一片天空拍摄4张照片，每次曝光间隔10分钟，然后在计算机屏幕上比较它们的差异。
They start by taking four pictures of the same patch of sky, with ten minutes between each exposure, and compare them on a computer screen.
您应该在工具完成每次尝试时在屏幕上看到一些活动。
You should see some activity on the screen as the tool completes each attempt.
请按照屏幕上的说明执行相应的操作，但是在提示设置密码时，不要进行设置，因为您需要在每次输入密码时使用这个密钥。
Follow the on-screen instructions, but don't set a password when prompted, as you will then need to enter the password each time you want to use the key.
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