Star Trails

[Xmetal]

Just me again

I'd love to know how to take shots like this...

The only thing I know would be to point the camera south (don't forget i'm in Great Southern Aussieland), aim for the sky and lock the shutter open.

Now the things I want to know is:

- What film should I use?
- Wide Angle Lens? What appeture setting? (my W-A is 35-70mm, f2.8-22)
- How long should I leave the shutter open for?
- should i worry about condensation or other weather-related issues?

I'm guessing that covers everything....

Thanks in advance for any assistance! :sillysmi:

 

[DarkEyes]

I can help you out with this one.
Slide film is best for thes shots, otherwise ISO 100 film is the go (Something with low grain is needed). The shot you've displayed above was exposed for the entire night (Note the star trails make Semi-Circles- means that during the exposure the Earth Made a half turn on it's axis (~12 Hours). Shorter exposures than this are ok, but you want at least 2 Hours to be worthwhile.

Star trails need to be done under really dark skies. The camera must be aimed exactly at the south celestial pole. to find this point, use a compass to locate due south, then aim the camera at A figure of degrees above the horizon equal to the degrees of latitude of your location. (Note: Beware of hills etc. these can throw your aim off.)
From memory, a lens at 50mm with a low f/Raitio is the best set-up for star trails.


For best info on this topic, sign up to the forum at www.astronomy.com. You will find heaps of help there.

 

[Dollface]

I can clarify a point that Dark-Eyes has made..

I have just returned from Uluru, and while I was there I did the "Sounds of Silence" dinner, where an astronomer comes and talks you through the Southern Sky at night.. And can I say, it was the most amazing night of my life - I saw the Smaller Magellen Cloud - and that is 190,000 light years away...

Anyway - You first need to find the "South Celestial Pole"..

"Alpha and Beta Centauri, known to Southern Hemisphere residents as The Pointers. ( below the southern cross )
By drawing a line bisecting these two stars, and looking for its intersection with a line drawn through the long axis of the Southern Cross (Crux), due South is accurately found. The point at which those lines join, the South Celestial Pole"

And also, you don't need to do it under dark skies. I asked the astronomer, Because I told her i was very interested, but I would have to be out of the city to do it, right? Wrong. because of the length of the shutter speed ( ie: 6 hours ), even the faintest amount of light will be picked up, and the camera will see "through" the ambient light of the city - of course, you can't have direct light coming in through the lens, so perhaps your backyard - or a golf course would be perfect.

Hope this helps.. I did some long exposure shots during the dinner in Uluru - once they are processed, I'll post them!

Edit: Here is the best place to look

http://www.sydneyobservatory.com.au/astronomy/current_night_sky.asp

( they actually have nights where you can attach your SLR to their telescopes - i have pictures of Saturn...)

 

[mentos_007]

ok but any advice on exposure? If I set my camera on... 3 hours for example... what apperture do I need not tu burn everything? f/22 ?? f/16 ??

 

[Skipster]

I find F2.8-4.0 works well. Again, the sky must be dark, no street lights or bright moon. Dew is a huge problem and can be blocked from above with a tarp or umbrella. I have some I took while I was out one night. I'll see if i can find them and scan them.

 

[Dollface]

ok but any advice on exposure? If I set my camera on... 3 hours for example... what apperture do I need not tu burn everything? f/22 ?? f/16 ??

Not sure... I suppose the best way to do it, would be to bracket and to run it first for an hour, then 2 - but I would think F11-16 would be appropriate..