Quick Guide to photographing star trails

Welcome to the first of what I hope will become a useful series of 'Quick Guides'. I have had a few requests for help with various aspects of photography, design and software that I have a bit of experience with and it seemed the best way to share this information was to create these 'quick guides'. They are by no means meant to be definitive but are intended to give you a solid starting point to get out there and have a go yourself.
The first is a guide on photographing star trails, you should be able to download and print off the guide here and take it with you for reference.
Please let me know how you get on, shout with any suggestions or corrections and have fun! Please checkout my gallery to see some example star trails I have made.

location
compass to get the centre of the star trails you need to know roughly where North and South is.
compose image foreground interest is good
temperature if it gets too cold your lens will fog up. I use chemical hand warmer pouches strapped to the lens.
minimise light pollution from towns, roads, airports etc.
clear skies check your local weather service for cloud cover.
moon a full moon is great for lighting up the landscape for more interest, but it will also make less stars visible.

tripod
set as low as possible don’t knock it in the dark! I have knocked the tripod without knowing and ruined a nights shoot. I’ve also managed to shoot a full night completely out of focus... arty!

DSLR camera settings
shutter mode manual
shutter speed manual 30 second
f2.8 or the largest aperture available
ISO 1000. Increase ISO if you have a slower lens
file format jpg raw files add too much extra work
Long exposure noise reduction off
set camera to automatically shoot pictures to set Nikon interval timer shooting;
1 press ‘menu’ and select the ‘shooting menu’
2 scroll to ‘interval timer shooting’
3 select ‘start time’’ and set to about 5 minutes ahead.
4 now set the ‘interval’ to 00:00’ 33”
5 set the number of shots to 999x1 = 0999 and select ‘on’

lens
as wide and fast as possible
manual focus to infinity
double check focus before you shoot

process
the longer you shoot the longer the star trails
stack images and set layers to lighten using editing software like Photoshop
1 open photoshop and go to file/scripts/load files into stack
3 click ‘browse’ and select the first 50 files only, click ‘load’
4 select all resulting layers and set layers to ‘lighten’
5 flatten image and repeat with the next 50 photos
6 copy and paste resulting images into one photoshop file, set layers to lighten and flatten image.

checklist
camera with charged batteries
plenty of card storage
tripod
lens & warmer system
compass
torch
warm clothes
check moon phase
check weather