Some stars being watched have very variablebrightness. That is confusing for computers, but for human eyes is less of a problem.
一些观测中的恒星亮度变化较大，这对于计算机来说难以把握，但是对于人眼却不成问题。
2
On the Fenix, there are four brightness levels on the UI, with a variable-frequency strobe mode accessible by simply holding down the silver side button.