Star Trails

[bluefish]

Truly, I need help in all aspects of it, but one of my most pressing questions is how do I keep my shutter open for an hour and longer? Right now I can only get it to stay open for a minute or so.

I'm really interested in taking pictures of star trails, which requires the shutter to be open for a length of time.

[Ads]

[cosmonaut]

It's fairly easy to do. I don't think you can with a DSLR, It's shutter isn't designed to stay open that long and the battery will run down. You need a film camera and a wide angle lens and a locking shutter release cable. Point it to an interesting part of the sky, focus to infinity. press and lock the cable and go get a cup of coffee. I would try different lenghts of time to have the shutter open. You will get a green tint to your pictures the longer it stays open. And use a higher speed film 400 or 800 should do.
Cosmo

[Torus34]

You'll reach a limit on exposure time due to the light pollution of your site. The darker your site, the longer you can expose before you end up with a sky that's so light that it begins to gobble up the trails of the fainter stars.

You can control this for longer exposures [longer trails] by stopping down, but again you'll lose some of the fainter stars. With a bit of experimentation, you'll arrive at the 'best' exposure [time and aperture] for your site.

Any decent old manual 35mm SLR with a standard lens should get the dog walked. These are very inexpensive, particularly brands other than Nikon [all], Canon [all] and that old favorite, the Pentax K1000. The off-brands often have good lenses and you don't pay a premium for the name.

Don't overlook using one of the old 6x6cm twin lens reflex rigs. These may meet your requirements, though your aperture will be limited to f3.5 max.

And do use a lens shade. Anything you can do to keep stray light out is worth while doing.

[rmh159]

... I don't think you can with a DSLR...

Actually you can with DSLR's as long as they have a bulb shutter speed (which I think most do). Typically the bulb feature lets you hold in the shutter release for as long as you want and when you let go it'll close the shutter but you can get remote triggers that let you open the shutter when pressed and close the shutter when pressed again.

So a DSLR with bulb + remote = shutter speeds of 1 hour

I'm not sure about the battery issue. I believe if it dies while the shutter it open it simply closes it and turns off but I haven't run into it myself so I can't verify. I can say though that the battery I have with the D50 lasts a looooong time and if you'd charge it up right before the shoot I don't think it'd be an issue.