Digital Star Trails

[mjs1973]

I know this image has some major flaws, but I wanted to share it anyway. What you are looking is the result of 97 seperate exposures. I did this as an experiment to see how it would work. Here's what I did. I set up the camera and tripod to where I wanted it. I set the shutter speed to 30 seconds, ISO @ 400, adjusted the f/ stop to where I wanted it, and switched the camera to continuous shooting mode. I used a cable release and locked the button down. There is a bit of a lag between each shot, after the first 4, because of the DRebels 4 shot burst limit. After 4 shots, the camera would have to pause, and write a file to the card before it could take another one.

Then I took the files into PS. I opened the first shot and used that as my base image. Then I took the second shot, copied, and pasted it onto the first image which created a new layer. Then I right clicked on the new layer and selected Blending Options. In the Blend Mode option box, I selected Lighten and pressed OK. Flatten the image and onto the next photo and so on. It took some time, but I'm sure you could create an action or two to automate the process if you want.

For the final step, I took the file into Noise Ninja and cleaned up the noise a bit. I read that you should take an initial shot with the lens cap on and use that as your starting photo, to keep the noise levels down, but I didn't read that till I was done.

[ken1953]

Seems like an awful lot of work, but I imagine the learning was well worth it, and the image you came up with is very interesting. Nice work.
Ken

[mjs1973]

Hey Ken,

It was a lot of work, and not something I plan on repeating. Future star trails will be done with film. The learning experience was worth it tho, and if someone else want's to give it a try, the info is here for them.

[jar_e]

Definately an interesting way of doing things. How long can the shutter be open on the Drebel?! Wouldn't it just be easier to keep it open for five/ten minutes?

Jared

[mjs1973]

Jared,

The slowest shutterspeed the DRebel has is 30 seconds. It does have a bulb setting as well, so I could have just left it open for as long as I wanted. One of the problems with digital tho, is the increase in noise with longer shutterspeeds. I used the 30 second exposures to help reduce the amount of noise in the image.

[jar_e]

Ah, I got ya Michael. Neat shot and idea though nonetheless!

Jared