For week five I have had a go at long exposure star trails. These images were taken using a Canon 550D and a cable release. For this process I used a low ISO and started at 5 minutes and doubled the the exposure time until I got to 20 minutes. I kept getting an orange glow from the village below which i think was spoiling the images but overall I think the final image came out better than I imagined. If I were to take these images again I would use a higher aperture and possibly choose a remote location to avoid any light from below spoiling the image.
f/5.6
ISO100
55mm
301s exposure
f/5.6
ISO100
55mm
600s exposure
f/4.5
ISO100
18mm
1241s exposure
f/4.5
ISO100
18mm
754s exposure