Star Trails – focussing?

[hoffy]

Howdy all,

It looks like we have relatively cloud free skies tonight, so I am planning to go out tonight and try some Star trail trials. At this point I am planning on using my Bronny SQ-Ai and 80mm PS lens loaded with Ektar. The plan is to shoot at either F5.6 or F8 for around 1 to 2 hours. (I want to try for at least 2 hours, but it all depends on what others want to do, as I am just tagging along).

The main thing that is puzzling me a little is where I should be focussing with such a setup – Should I set on infinity and hope for the best, or set it back a bit?

Any advice would be welcome!

Cheers

 

[Poisson Du Jour]

Set focus to a distant object like a tree (focus in the evening while you can see detail), then remember or set the position and aim the camera up. But not just anywhere up! Locate the Southern Cross. Next, place your thumb and index finger on the cross-beam (horizontal line of two stars that form the cross) and duplicate the length three times to the right. This approximates very closely the South Celestial Pole (which has the distinction of being around the 3,000th faintest star... ) around which all other stars rotate. This is the best effect but of course the location and contextual interest (tree(s), buildings, rocks etc) will determine how and where you set up. Keep the camera safe and yourself amused (and warm!) for 2 to 3 hours. f8 will give you more star trails but will need a longer exposure. I favour f6.7 to f8 maximum, no filters. Here in southern Victoria there is high streaks of cloud but that should clear up. I am planning star trails too on the weekend. Watch out for the moon (in last quarter). It rises at 11.51pm tonight (Friday). The moon, even a crescent, can turn night into day and ruin a star trails outing. New Moon nights are the best.

 

[hoffy]

Cheers - perfect info there! I am sitting waiting for my ride - its already dark, so I will have to guesstimate focus...dammit! We are going to do it over the ocean, well, kind of - I am planning on pointing the camera South West to see how it goes (most of the coast around Adelaide points West). Like I said, its a trial of a trail, so I'm not going to be too peeved if it doesn't work out.

With any luck, I'll open the shutter at around 8:30 - which gives me a good 3 hours before the moon starts to rise....which reminds me, I better find my hip flask!

As for F stops, yes, I had decided to split the difference between 5.6 and 8 as a starting point.

Cheers

 

[Worker 11811]

Locate the Southern Cross. Next, place your thumb and index finger on the cross-beam (horizontal line of two stars that form the cross) and duplicate the length three times to the right. This approximates very closely the South Celestial Pole (which has the distinction of being around the 3,000th faintest star... ) around which all other stars rotate.

The closer you point the camera to the pole, either north or south, the more circular the star trails will be. The farther east or west you point, the more the trails will appear as arcs until, ultimately, if you point due east or due west, you'll see nearly straight lines, depending on your lattitude. If you point due east, the star trails will appear to rise. If you point due west, they'll appear to set.

You probably won't be able to tell "rising" from "setting" in the resulting picture but the point is to be able to look at the stars in the sky at the time you start taking the picture and predict which way the trails should lead when you're done.

This isn't an exact science. Just a few items to give you some idea of what to expect.

 

[Poisson Du Jour]

My time-honoured motto for star trails is never expect perfection; it could well come unexpectedly: you are out there to have a bit of fun, not to make an exact science of photographing the heavens, but just for entertainment. With good planning and an awareness of your position relative to the stars, good results will be a given. But never ever be discouraged or put off by blank frames — or even falling asleep (Hoffy has it right by having a hip flask at the ready!!). And do experiment with film, like tungsten film that gives a blue, daylight-like hue to the scene (my next trick).

 

[Poisson Du Jour]

My time-honoured motto for star trails is never expect perfection; it could well come unexpectedly: you are out there to have a bit of fun, not to make an exact science of photographing the heavens, but just for entertainment. With good planning and an awareness of your position relative to the stars, good results will be a given. But never ever be discouraged or put off by blank frames — or even falling asleep (Hoffy has it right by having a hip flask at the ready!!). And do experiment with film, like tungsten film that gives a blue, daylight-like hue to the scene (my next trick).