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How can I get this effect where the stars are seen as lines? Do you need a special camera?

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mattdm
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Antonio Jafonso
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2 Answers2

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This technique is called "Startrails" and you don't need to have a special camera. All you need is:
- tripod
- time-lapse control to shoot lot's of photos
- fast lens (large aperture)
- compass
- startrails software (it's called Startrails.exe and you can find here)

Your camera will shoot for a long time (it depends how is the effect do you wanna get, in your example were about 2 hours). The Compass is necessary to find the earth's axis, it's more beautiful. After you shooting, you have to match them and that's why you need the startrails software. It's very intuitive, drop the pic and click 'start'.

For more information, check this: http://www.lightstalking.com/how-to-photograph-star-trails

Update:

There are two ways that you have to do a startrails: a single photo (with a very long exposure) or shorter photos. In my opinion lots of photos are better instead of just one because the a long exposure you can get more errors than the first method. If something goes wrong (unplanned lights) you lose everything, so it's safer to do several photos.

Edilson Borges
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  • A discussion of the tradeoffs between stacked exposures or a single long exposure would be very valuable (the linked article has minimal practical information on this topic). – Szabolcs Aug 22 '13 at 18:32
  • Totally agree with you @Szabolcs, this information is very important. I've updated my answer, thank you. – Edilson Borges Aug 22 '13 at 18:55
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    The example that was given was no more than 30-45 minutes since the angle spanned by the star is no more than 10 degrees. A compass is not required as long as you can find the Big Dipper in the sky and then, from that, figure out were Polaris is using the following: http://simbelmyne.us/sca/haversack/the-location-of-the-north-star-206.gif – Francesco Gallarotti Aug 23 '13 at 11:59
  • Agreed with the exposure time and about the compass, @FrancescoGallarotti, but it's hard to find the Polaris if you don't have experience (I've already tried this method and it was ok), and to be more precise you better get one. (I'd used the Google Sky map app for android and worked more or less) – Edilson Borges Aug 23 '13 at 12:32
  • You'll also want to avoid the moon. You don't have to wait for a new moon like the article says, you can wait until the moon sets (as long as it's gone at night). You should also turn off dark frame subtraction if that's enabled on your camera, or you'll dashed star trails. – walter Aug 25 '13 at 07:32
  • I also prefer multiple exposures. In addition to the reasons mentioned above, you'll probably end up with a higher quality image, and you have the option to combine the images in multiple ways if you keep them separate. – walter Aug 25 '13 at 07:39
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Star trails occur because stars "move" across the sky as the Earth rotates, and so when a camera keeps its shutter open for an extended period of time it will absorb this moving light as light trails. For longer trails, other techniques can be used to combine multiple photos of stars. For example, Adobe Photoshop has an "Apply Image" feature that can be used to combine photos. As edilsonfb points out, however, there are some dedicated software products that focus on combining star images.

The circular pattern occurs due to the fact that the Earth rotates rather than slides across the universe. To get the circular pattern, point directly north if you live in the northern hemisphere or south if you live in the southern hemisphere.

stimpy77
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    While informative, this doesn't actually answer the question, which is asking how the star trails are achieved, not why they are circular. –  Apr 12 '15 at 08:22
  • Yes it does. Perhaps you need to re-read? ".. when a camera keeps it shutter open for an extended period of time .." is an explanation on how trails in general can be achieved, "For longer trails, ... combine multiple photos..." elaborates, and "To get the circular pattern, [instructions continue]" is an explanation on how the circular pattern is achieved. (Circular was included in the question, see question title.) – stimpy77 Apr 13 '15 at 14:44
  • Also, my motivation to post was because the other answer, from edilsonfb, did NOT clearly explain how to get the circular trails, which is what the question DID ask. "Compass is necessary to find the earth's axis" was mentioned but it wasn't clear so I elaborated in saying "point directly north if you live in the northern hemisphere or south if you live in the southern hemisphere". – stimpy77 Apr 13 '15 at 17:49
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    Your sentence about Photoshop was added after I made my comment, and there is nothing in your answer about, e.g. using a tripod, what aperture/ISO settings to use etc. It's more of an addendum to the original accepted answer, so would be better off as a comment than an answer, unless you wanted to add more detail to make it a fully self-contained answer. –  Apr 13 '15 at 18:11
  • I added my sentence about Photoshop without regard to your comment, because I thought it was a detail worth adding to my already valid answer. I posted my initial reply to your comment before I added the Photoshop addition. Also, my answer is my answer. This isn't a wiki; there doesn't need to be only one answer for all to append to. I'm fine with the down-vote on the basis that my answer is not a very complete answer, but I'm not fine with your assertion that I didn't answer the question at all. – stimpy77 Apr 13 '15 at 19:09
  • Pointing directly north is the key in making the trails circular - now the patterns make sense – eigenjohnson Oct 13 '16 at 12:09