Ok, I'll try
Sorry about my English ..
The alarm clock wake me up at 1am. I dressed up and went outside. My goal was to take one picture. Earlier in the day, I had decided to go and take my third star trail photo.
As I drove towards the scene, I calculated the aperture, sensitivity and the length of time needed. I estimate that the shutter speed should be about 1,500 seconds. I had also decided to try to capture star trails with my cell phone. That caused some trouble. How would I measure the time?
I calculated that the first four songs of Metallica's Master of puppets lp would take somewhere around one and a half thousand seconds in total. So, after humming the songs in my mind, the exposure would be ready.
I arrived to the river and crawled beside the flooding, roaring rapids, and arranged the camera firmly on the beach rock. The rush of the river was scary and I was glad to get back to the bridge. It was time to play mental Metallica.
When I got to the song "Sanitarium" on the album, I went back to the camera. And this time without a flashlight. I didn't want to ruin the exposure in the last minute. When Sanitarium's last drumfills run through my mind, I stopped the exposure, put the camera in the bag and walked to the car.
After I opened the picture, I saw that it was ok. And the final exposure time was 1660 seconds. The actual song duration of the four first songs with breaks is 1640 seconds ...