Taking photos of the night sky involves long exposures and with most cameras only going down to 30 seconds exposure it means that you have to use some other means of controlling the time. Using a Timer remote control is the best way, this is also know as a intervalometer which then enables you to control the exact length of time the shutter is open.
I would normally set the control unit up before going out to save time, although the display does light up so you can see what you are doing out in the field. In addition I should point out that it doesn't have an off switch so make sure you take the batteries out when you have finished otherwise you will have flat batteries when you come to use it again.You can normally pick these up for around £20 but wouldn't advise the cheapest ones.
You can also use the control to take long exposures without setting it up. Just slide the button up into the lock position then you can set the camera up for continuous shooting say at 30 seconds on the caera at f/4 for star trail photos. Having taken around 100 photos use Star Trails free software to combine them all into one photo
Have a great Christmas and hope you get some clear still skies near you.Thanks again for looking at this blog, why not try my other Shetland blogs: