DSLR startrails

Shooting startrails with a DSLR offers new challenges which we didn't have to face with film. In "the good old days" I'd simply setup my tripod outside the tent, start the exposure, set my alarm for a couple of hours later - and go to sleep.

No such luxury when shooting digital! Thanks to "noise", startrails need to be taken as a number of exposures, then "stacked" using software to create a single image.

At first I found this annoying, tried different techniques (starting with taking the minimum number of exposures for the maximum acceptable time noise-wise) and stopped taking so many startrails. But now I've perfected a technique and am enjoying them just as much as(or possibly even more than) before.

First, I set up, and take one 30 second shot. Then I preview - does the foreground get blown out over 20 seconds? Are there enough stars in the background in the correct places? Etc. Then, leaving my camera set to 30 seconds, I set my cable release to take a continuous burst and then leave it for at least an hour. It's just like the good old days! I can take a walk, cook up some dinner on a BBQ (a distance behind the tripod, obviously!) or even take a nap.

I particularly like the 30 second time as it tends to allow the foreground to be nicely exposed at night as well. In the image below the full moon was setting behind me - when shooting with film startrails were practically impossible at full moon. But set to 30 seconds, the rocks in the cliffs ahead were nicely exposed, without looking like a daylight shot:

This took about 160 30-second exposures, but was well worth the effort (IMO :) )

So, startrails are back on the list of things I take frequently. And no matter how much I'd like to take all the credit, the fact that the D90 performs admirably in low light conditions helps too :)