大峽谷直升機時段選擇 - 拉斯維加斯

明年1/29~1/31會到LV，屆時想參加大峽谷的直升機旅遊
行程: 飯店接至機場(Boulder City)，起飛去遊覽，回機場，巴士回飯店
目前在選時段的時候很猶豫(1430 or 1600)，也寫信去PAPILLON問了
回覆如下:

The times shown online are the departure times, pick up is approximately an
hour and a half prior to this time. I would definitely recommend the latest
flight for the best lighting. The full duration from pick up to drop off is
about 4 hours, so for the 4:00 PM flight, pick up is about 2:30 PM and you'd
return to your hotel around 6:30 PM. Let us know if you have any other
questions.

但是在這個網站上查，今年一月底的SUNSET時間大約是1705左右
https://www.timeanddate.com/sun/usa/las-vegas?month=1&year=2016
4點準時起飛 會不會過沒多久就因為太暗看不到甚麼東西
還是我應該參考Astronomical Twilight、Civil Twilight這兩個時段
還請各位專家或是指導一下
謝~

--