For taking startrails, you can use stacking method. With stacking, you can even get nice startrail shots in urban conditions like Singapore. You can use a software called "Startrails" to create startrail shots at ease, available free of charge from
Startrails application
1). Focus properly; then, depending on sky brightness, choose suitable exposure time, aperture and ISOs. Normally for stacking, 30s exposure is enough. If you are under dark skies, set aperture wide open and high ISO; if you are in urban area, set to smaller aperture and lower ISO. As soon as you get proper exposed single frame, neither underexposed nor overexposed, you can move on to step 2.
2). Say you want a 1-hr startrail, simply take 120 photos using the same settings. For Canon 450, if you want to take 120 photos continuously without manual efforts, you'll need to purchase a timer remote control, or simply use a laptop to control. One point to note, the more photos you stack, the higher the signal to noise ratio.
3). Before or after you take all the single frames, put on the lens cap, take one more frame at same settings. This is called a "dark frame". By stacking this frame afterwards, the hot pixels will be killed.
4). Upon finishing taking all the neccessary frames. Import the light frames into the Startrail software, and import the dark frame also. Then press the startrail icon, stacking process begins; soon enough you'll get your result. Very easy.