Star Trails

My first star trail.

Stars move in the sky during the night, in the Southern Hemisphere they revolve around the Southern star (Northern Hemisphere - the North Pole Star). If you go out on a dark night and set up a camera on a long exposure (like 20+ min) then you can capture a 'black hole' type of effect in the photo. This was taken in our back yard in Wellington NZ.

This was taken with a Canon EOS 400D, Digital SLR. I used a 77mm wide angle lens at a focal length of 10mm (Lens Model: EF-S10-22mm f/3.5-4.5 USM) on a 20 minute exposure time at f3.5, ISO 100. When using a remote control on Bulb setting, the shutter will open the first time you press the button and will close the next time you press, this saves you having to hold down the button for 20 min ;)

In this attempt, there is too much light coming in from the bottom of the photo which is caused by a highway in the background. I took another picture later in the night when the road was quieter and there were not so many headlight flashes and raised the fstop number to f6 but the camera battery went flat.

When using digital cameras for extra long exposures it is worth keeping in mind that all the time the shutter is open, the digital processor is working and consuming battery power, not only that but I found when using an exposure time of around 20 min, even after the shutter has been closed, the camera takes a further 20 min to process the picture and write it to the flash card, it was during this time that the battery went flat and unfortunately I lost the photo. I need to experiment and see if the same still happens when using RAW mode.

I found this page very helpful:

http://www.danheller.com/star-trails.html#1

Cant wait until the weather conditions are right for another go. I just wish I knew about these when we visited the Frans Josef Glacier last year.

In brief, here are the steps required:

• Pick a night close to a new moon (for complete darkness).
• Use a wide angle lens (to get the best circular effect).
• Use a steady tripod.
• Set your camera to Manual.
• Set exposure to Bulb.
• Set aperture setting as low as possible (f3.5 for example).
• Point your camera toward South for the Southern hemisphere and North for the Northern hemisphere.
• Open the shutter.
• Go make a coffee, have a cigarette, drink coffee, have another cigarette.
• Close the shutter.
• Go make a coffee, have a cigarette, drink coffee, have another cigarette.
• Check out your photo.

Of course steps 9 and 11 are not compulsory and can be replaced with any other activity which you think will take a similar 20 minutes