With this in mind the first thing you are going to want to do when imaging the night sky is to get out of the city. It isn’t practical in England to have truly dark skies but you can give yourself a fighting chance.
In this section I am going to deal with simple straight forward night sky shooting and leave the stacking for another chapter.
An example would be my 17-85mm lens set at 17mm on a Canon EOS 7D So 17x1.6 for sensor crop thingy gives us 27.2ish, 600 divided by 27.2ish gives us 22ish. So to avoid trailing stars I would have to use an exposure of 22ish seconds. I'm using ish a lot because all of the setting are very ishy to be honest but it gives you a starting point. You will then want to open up the lens to it’s widest aperture and the close it one stop.
Switch your lens to manual focus and focus it to the infinity mark, that’s the lazy #8, it looks like a number 8 laying down for those of you that don’t know.
Now you will want to minimise any movement of the camera on the tripod whilst the exposure is taking place so if it is windy remove the neck strap and if you don’t have a cable release use the timer setting to trip the shutter. If you really want to go belt and braces you could also use the mirror lock up.
After you have your shot make any adjustments you feel are needed to the settings and take another shot. Again make any adjustments to ISO exposure etc and take some more.
If your really lucky you may even get a meteorite etc fly across your shot whilst the shutter is open.