Lets Go Streaking, a Guide to Star Trails

June 10, 2008 | Category: How To...., Nocturnal Photography, Photography

Ever since the first time I looked in a book with long-exposure photography, I’ve loved the look of trailing stars in photographs. The idea is simple, expose for a long enough period of time to record the rotation of the stars as the Earth spins. My own attempts were never very successful using film due to the negative effects of reciprocity and my lack of technical skills and patience. Even later, when I finally got a digital SLR camera with the battery life to pull off an hour long exposure, my star streak photos were always sub par, riddled with technical and aesthetic problems. One of my problems was that I always tried to shoot star streaks as if I were shooting a film camera: One very long, guessed exposure, teetering on the edge of my battery life. As I will outline, there are many problems with this technique and there is a much better solution!

The “Traditional” Method of Getting Star Streak Photographs

Things used to seem quite simple. Find a dark sky without too much light pollution, calculate an exposure based on the ISO, working aperture and phase of the moon, place your camera on “bulb” mode and expose for a long enough period of time so that the stars streak through the sky as the Earth rotates. As simple as this seems, there are many problems with this method. For one, while digital cameras don’t have the issue of reciprocity like film does, they do have the inherent problem of noise. Without getting too technical, all digital cameras use an internal imaging device to convert light into an electric charge, this is either a CCD or a CMOS in most cases. As the camera exposes, and depending on the ambient temperature, the sensor begins to heat up and produce thermal noise or dark current. This can heavily degrade the detail and quality of an image. Most modern digital SLRs have built in long exposure noise reduction by silently taking second “dark frame” for the same length of the first, thus removing the dark current. One of the major problems with the built in noise reduction is that in order to be effective, the camera has to noise reduce under the same ambient temperature as the original exposure(meaning the photographer has to stay on location for twice the amount of time), the other problem is battery life limitations. With my older Nikon D200 + battery grip, I could pull off about an hour of exposure + an hour of noise reduction and just barely have juice to preview the final shot.

Another problem with the so called “Traditional” method is balancing a light polluted sky with the foreground. Unless you are just going for a shot of the stars in the sky and don’t care about any foreground detail, you are most likely going to be very frustrated when you find that the sky is too bright to make out the stars due to light pollution if exposing for foreground detail (see the photo on the left). City lights, car headlights and especially a large phase moon can light up the sky dramatically brighter than the foreground leaving you with the choice of either underexposure your foreground, or losing precious star detail and contrast by exposing for foreground detail. Painting the foreground with light is one solution, but doesn’t solve the other problems.

Stacking, the (Almost) Perfect Solution!

So instead of shooting a single long exposure, we can take a large number of short exposures equaling the length of time that our single long exposure would have been and “stack” them together. Let me clarify. Lets say you would like to have an hour long exposure of the stars moving across the sky. You could set up and shoot an hour long single exposure and run in to the previously mentioned problems, or instead you could do the following…

Shooting:

You’ll need a fully charged battery (battery grip is recommended), a cable release or remote, a tripod and a memory card capable of holding a few hundred shots.
Set your quality to .jpg-fine or RAW (Keep in mind that if you want to shoot raw, you will have to batch process a large number of files).
On a tripod, compose your shot and set your shutter speed to the slowest speed your camera will shoot continuously, most digital SLRs will shoot as slow as 30 seconds, don’t use bulb.
Taking a few test exposures, set your exposure (using your ISO and aperture) so that you can see stars in the sky. Don’t overexpose the sky, we want a fairly dark histogram, with a very small spike near the right for the stars. Also, don’t worry about getting too much foreground detail in your exposure right now, just focus on the stars.
Set your white-balance for the sky. This is a matter of personal preference and it will vary depending on the light pollution.
Turn off any kind of long-exposure noise reduction that is built in to your camera. High ISO NR can be left on.
Set your camera to continuous drive mode.
Lock your cable release/remote so that the camera is stuck firing continuously. Now the camera will shoot one 30 second exposure after another until you stop it.
Stop after an hour (or however long your predetermined exposure is). The longer you let the camera shoot, the more the earth will rotate and the longer the star streaks. Also, keep an eye on the camera as some cameras do not have the buffer to handle so many shots in a row.
Don’t move the camera! Once you’re done exposing, you still need to shoot a manual dark frame for noise reduction. Put your lens cap on, make sure the viewfinder doesn’t have any light shining into it and expose for 30 seconds.
The last thing you need to do it shoot a brighter foreground frame for the detail in the foreground. Put your camera on bulb, and make an exposure long enough to get good detail in the foreground, don’t worry about overexposing the sky. I recommend using the same aperture and ISO setting as the 30 second exposures for noise consistency. You can enable in camera long exposure noise reduction for this if you want, or you can shoot another dark frame with the lens cap on of the same length for noise reduction. I recommend turning NR back on for this if you have the time/battery life.
Go home and follow the next section for processing.

Processing:

Windows Users:
Note that Windows users can also follow the OSX instructions for a bit more work, but also a little more control.

Download StarTrails from HERE. We will also be using Adobe Photoshop CS3 (although you can probably use CS2 or even Elements 6).
Open StarTrails and go to File –> “Open Images” and select all of the frames except for the dark frame and foreground frame.
Go to File —> “Open Dark Frames” and select your darkframe
Click Build —> Star Trails and give it a few minutes. You can watch as the star streaks grow.
Save as a .tiff file and open the .tiff in Photoshop
Also open the foreground exposure jpeg and paste it as a new layer on top of your stacked .tiff file in photoshop
Create a black mask on the foreground layer and paint in the foreground carefully (see graphic above for example).
Apply curves, noise reduction and other editing adjustments and your done!

OSX Users:

Since the StarTrails Software doesn’t work in OSX, we can use Photoshop to do the same thing. Its a bit more work, but it gives you more individual frame control. There are two ways to do it:

Method 1: Use the CS3 script under File —> Scripts —> “Load Files into Stack.” Open all of your exposures except the foreground frame. Change each layer’s blending type to “lighten” and the dark frame’s to “difference.” This is time consuming and tedious. I recommend method 2.

Method 2: Download this Photoshop action (this does everything above automatically, except the dark and foreground frames). Follow the directions on the site (one step). I recommend deleting the action step where it flattens the layers. Then add your dark frame as a new layer, change the blend type to difference. Next add your foreground image as a layer, create a black mask and paint in the foreground. Apply curves, noise reduction and other adjustments as needed.

Almost Perfect? What gives?

While the stacking technique gives you a ton of control, it is definitely more work. Also, at large print sizes, small gaps can appear in the star streaks from the small gaps between exposures.

Some Tips

You can include the polar axis (rotational center) in your shot by including Polaris (the North star) in your photo (see the Tahoe photo at the top of this post)
Shoot during a new moon or smaller than half phase if possible
Look up local moon rise/moon set times so the rising moon doesn’t mess you up in the middle of an exposure
If you have a large budget, look at battery grips and/or external power sources for your camera such as Quantum’s Turbo 2×2 battery

Timelapses

If you took a bunch of stacking photos, you can always put them together as a time lapse like this:

That’s it for now, feel free to comment or contact me with any questions.

Tags: Dan Newton, How To...., Lake tahoe, long exposure, nevada, night, Nv, photographer, Photography, Reno, Star trails

53 Comments

Across The Sky » Lets Go Streaking, a Guide to Star Trails
on June 10th, 2008
1
[...] Lets Go Streaking, a Guide to Star Trails Lets say you would like to have an hour long exposure of the stars moving across the sky. You could set up and shoot an hour long single exposure and run in to the previously mentioned problems, or instead you could do the following… … [...]
Asa
on June 10th, 2008
2
Dan, that timelapse is so bitchin! Great article too.
jcgilmore
on June 10th, 2008
3
Excellent write-up, Dan – can’t wait to try it.

Coupla questions:
You said: Also, keep an eye on the camera as some cameras do not have the buffer to handle so many shots in a row.

My questios: Will a D200 handle it?

You said: Don’t move the camera! Once you’re done exposing, you still need to shoot a manual dark frame for noise reduction. Put your lens cap on, make sure the viewfinder doesn’t have any light shining into it and expose for 30 seconds.

My question: if the lens cap is on, why can’t you move the camera?

Thanks for the PShop action!
Dan Newton
on June 10th, 2008
4
JC,

Your D200 shouldn’t have any problems. The only reason that I say not to move the camera is because you still need to take a foreground frame. I usually take my darkframe before the foreground frame so that I don’t have to change the exposure settings on the camera twice.

Also note that the dark frame needs to be taken in the exact same ambient temperature. That goes for long-exposure noise reduction too.
» Blog Archive » Where are my Fireworks?
on July 8th, 2008
5
[...] Stacking is also great for startrails. The best directions on the web are on fellow shooter Dan’s blog. Comments [...]
Jon
on August 28th, 2008
6
Dan this tutorial is awesome, previously I have always gone for the 1 exposure method which I will probably continue to use for light painting but this makes a lot more sense for star trails. Will keep checking back as your blog appears to jam packed full of the kinda images I like and aspire to take. Will be adding you to my blog roll for sure.

Cheers

Jon

http://tdmphotography.wordpress.com/
Tim
on September 5th, 2008
7
Great stuff Dan, keep up the good work. You’ll be a smashing success in life..
Stjärnspår och mörka himlar « Eltongallery’s Blog
on November 1st, 2008
8
[...] och ta sig ut i naturen för att fånga stjärnspår på bild. Här har Dan Newton skrivit en bra guide till ett lyckat resultat. Glöm bara inte inte en thermos med varm dryck. Taggad med:guide, [...]
Wallace
on November 8th, 2008
9
How do you “Set your white-balance for the sky?”
You have written a very informative article…. I have been waiting for a clear sky for a week to try it all out!
Tony
on November 10th, 2008
10
Great article. I’m going to give it a try this week.

Couple of questions though;

1. If I did exposures to cover 30mins, does that mean I also have to expose a dark frame for 30mins, or does it have to be the same as one of the short exposures i.e. 30secs.

2. I was thinking of painting the foreground frame with light to get some details on buildings in the shot. Would this work just as well as taking a long exposure to get the foreground?

Cheers again for the article.
Dan Newton
on November 11th, 2008
11
@ Wallace: I’ll just experiment for the white-balance. I say “for the sky” because you can always change it when you are doing your foreground exposure. Usually I’ll start with auto and sometimes I’ll force it to daylight if I want a warm city glow. Go through your presets and see what works.

@Tony:
1. Your darkframe length should be as long as a single stacking exposure. So if you were doing 1 hour with 30-sec exposures, you’d use a 30-sec dark frame because it’ll match the noise of a 30-sec light frame.

2.painting the foreground works very well! Check out my Fort Churchhill photo for example. One advantage of painting while stacking is that if you miss a spot you can paint it in a later frame and the stacking process will always keep the brightest info in the shot so its hard to mess up painting.
James Bester
on December 15th, 2008
12
Hi Dan,

Love the guide and have spent the past few nights in my garden looking up and experimenting.

I am using a Pentax K10d and would just like a ask a quick general question; on a 30 sec exposure the k10d processes for 30 sec’s after taking the picture leaving me with dotted star trails – is there a work around for this or is it because I have a more entry level camera?

See examples;
- http://www.flickr.com/photos/pentaxjunkie/3109465115/
and
- http://www.flickr.com/photos/pentaxjunkie/3109464979/

Cheers and again thanks a million.
James
Dan Newton
on December 15th, 2008
13
James,

The 30 second processing is your camera performing long exposure noise reduction. On the k10d, I believe that there is a custom function to turn it off.

-dan
James Bester
on December 16th, 2008
14
Dan, thanks a million – I have turned it off. I must say I suffered from the depleted battery syndrome after an hour of exposure time + another hour of processing time. This is the reason I had pretty much stopped taking star trails. Now it is a whole different matter, Thanks again for the great tutorial and the inspiration.

James.
Ziganny Photography’s Light Diary » Blog Archive » Star trails and landscapes
on December 19th, 2008
15
[...] has written an excellent tutorial on this which you can find on his blog Liquid in Plastic, click here to read this wonderful post. The tutorial shows you how best to capture the source images and how [...]
Rob
on December 22nd, 2008
16
Excellent tutorial on making startrails. The tip on shooting a foreground exposure and masking out is something I have not tried. Thanks for the tip!
Johan
on December 30th, 2008
17
Thanks for this great tutorial!

Your great photos help as inspiration
/johan
HDR-fotografen
on January 23rd, 2009
18
Thanks man. I will test it directly.
Brady Dyer
on January 30th, 2009
19
Thanks Dan! Good write up. going to have a try of this next week =) Will let you know how I get on haha.
Andy Parker
on February 24th, 2009
20
Hey Dan, great work and great tutorial! Just a few questions about your time lapses as I am looking into doing some of my own:

What kind of shutter speed, iso etc. did you use for the time lapses?

How often did you take a photo and for how long?

In the edit, how many photos per second did you do to make the movement of the stars look as smooth as you have?

all the best and keep up the great work!
Brandon
on March 15th, 2009
21
Dan,

Can you tell us what software you used to make the time lapse video? I just took some pictures for a star-streaker, but when I came back to the camera the fog had really rolled in. Needless to say I don’t have star streaks, but I can make a cool video of the fog rolling in.

Thanks.
Dan Newton
on March 15th, 2009
22
Brandon,

I used quicktime pro to put together the frames. I usually use windows movie maker to add music/credits etc.

The star stacking software that I linked to will also put together movies, but with less export and compression options.
Jay
on March 29th, 2009
23
I found your youtube video and came here. Great article, really nicely explained. I’m on my second night of star trail experiments, but live near to London so its a very orange sky. Would love to be out in the Nevada wilderness!
Ryan
on May 6th, 2009
24
Hey Dan,

Awesome work. Thanks so much for the tips! This is a whole new approach! If your ever near the bay area Id love to tag along for a shoot.
Ryan
Chris
on May 19th, 2009
25
Good article. I have been meaning to give this a go, but have struggled to find a free night, a dark location, a clear sky and no moon…but it’ll happen some day.

You say there are small gaps in the start trails when you use the stacking technique. I recall reading another article somewhere that described a technique to overcome this, but don’t remember where. Might be worth looking into.

Chris
tom
on May 21st, 2009
26
Thak you vey much!! this post is amazing!!!
Or Eitan
on June 21st, 2009
27
Hey! awesome technique. works perfectly when theres alot of different light sources around and long exposures arrnt possible. thatnks alot heres a result i got using Your Technique… thanks for the Tut!

http://sevenths.deviantart.com/art/first-try-at-startrails-126462784
help: star trails software
on July 20th, 2009
28
[...] [...]
Outdoors Night Shots
on July 28th, 2009
29
[...] [...]
Chris
on August 2nd, 2009
30
The linked url for the Photoshop action is reported as an attack site (2 Aug 09).

“This web site at http://www.schursastrophotography.com has been reported as an attack site and has been blocked based on your security preferences.”

“What happened when Google visited this site?

Of the 5 pages that we tested on the site over the past 90 days, 1 page(s) resulted in malicious software being downloaded and installed without user consent. The last time that Google visited this site was on 2009-07-28, and the last time that suspicious content was found on this site was on 2009-07-28.”

Any alternatives?
Andy Lejman
on August 30th, 2009
31
Hi Dan, great work and the article as well. I’ve tried star trails once and had to expose single frame for 50 mins, because I had not heard about the software. I use Mac and unluckily the Elements. As you are probably aware, that combination has not got any software I’d know, do you? Surely there must be something somewhere…
Do you still use 2001 version?

Any comments will be appreciated.
scott Thigpen
on November 21st, 2009
32
Hey there,

I’m having trouble with exposure and making sure things are in focus. I’ve tried iso 100, f4 all the way to f18. I get horrible results plus when I set my wide angle on infinty, it always comes out blurry.

any ideas?
Anonymous
on November 23rd, 2009
33
[...] [...]
Star Trails – An Easier Guide « Central Illinois Photoblog
on November 25th, 2009
34
[...] perfectly at home with that idea on a cold night actually. But to make it even better, I found a tutorial about star trails on the Interwebs this morning from Reno, NV-based photographer Dan Newton that absolutely rocks. [...]
Lets Go Streaking, a Guide to Star Trails. « Cooper Ricketts Photography Blog
on November 27th, 2009
35
[...] looking on the internet for tips and inspration on tis type of photograpy when I found this site Liquid Plastic photography go look at the site for more tips on star [...]
Justin
on November 28th, 2009
36
That timelapse is beautiful.
tagoshu
on December 17th, 2009
37
You can generate star trails for time lapse movie by using my “Afterimage” plugin filter for VirtualDub (freeware):
http://www.celestial-spells.com/logs/2009/12/virtualdub_afterimage_filter.html
Sitanshu
on December 17th, 2009
38
can a 500D handle it?
links for 2009-12-17 « AB’s reflections
on December 17th, 2009
39
[...] Lets Go Streaking, a Guide to Star Trails : Liquid in Plastic – Photography and Words by Dan Newto… Combining multiple photos (tags: photography photoshop tips howto technique star tutorial) [...]
Ziganny Photography Light Diary » Blog Archive » Star Trail Photography Video
on December 23rd, 2009
40
[...] blog http://www.liquidinplastic.com. He has blogged about his techniques for star trail images (read it here). Today I found this video of his which shows the creation of some of these images. Keep it up [...]
Twitted by soni_amit
on January 12th, 2010
41
[...] This post was Twitted by soni_amit [...]
Twitted by elars
on January 12th, 2010
42
[...] This post was Twitted by elars [...]
Sloth
on April 12th, 2010
43
dan,
awesome article,, cant wait to get out there and try your technique..
is my d60 sufficient to do star-trail..? or should i consider to get a d300..

cheers,
Dan Newton
on April 12th, 2010
44
Your D60 will definitely work. Good luck!
Karl Beath
on April 19th, 2010
45
Dan

I have been searching the net for about two hours until i bumped into your article. Absolute winner…explains it really well.

I used to star traces on my pentax 67ii, which i sold last year, and thought that with a dslr that wld be the end of the occasional star image.

Thanks
Karl
Greg Downie
on April 21st, 2010
46
Great guide, has helped me hugely with starting out.

Just maybe an update to your OSX/Mac users. If they use Photoshop CS4, you can select

File > Scripts > Statistics, pick your images. Set the mode to ‘maximum’ and let the computer do its work.

Works with Raws, nef, tiff, jpg etc. I find the results to be the same as using Star trails on a PC, which is good if you have shot in RAW. Same applies to PC CS4 obviously too.
Fernando
on April 22nd, 2010
47
Great Article cant wait to start taking pics…Just got my hands on a Canon T2i…Been reading the manual and looking for the continuous drive mode…But apparently it wont let me put more than 10 secs…So, Im assuming every 30 seconds manually I will have to do this?
Stephen
on April 29th, 2010
48
Great article! I’m looking forward to trying this, but I just have one question: I’ve noticed that in some of your photos you are in areas with some ambient light. Now, if I’m understanding correctly, by doing this method one doesn’t necessarily have to be in the absolute darkest place in order to get a good star trail shot. Is this correct? It would be good to know as I live in a fairly urban area with darkER areas, but not really one of those truly pitch-black-middle-of-nowhere areas unless you go much further out. Thanks! Keep up the good work.
Dan Newton
on April 29th, 2010
49
Stephen,

That is correct. By using the stacking method, you are able to keep the ambient light in check and prevent the sky from blowing out. You’ll find that under very dark skies, the stars stand out more, but it is certainly possible to get star trails in light-polluted areas.
Star Trail Photography | Imaging The Night Sky
on June 21st, 2010
50
[...] Video by Dan Newton Dan probably has one of the greatest How-To’s on Star Trail Photography Lets Go Streaking, a Guide to Star Trails [...]
Ian
on July 6th, 2010
51
Hey Dan,
Thanks for putting this guide together. I’ve been wanting to try my hand at this for a while now and finally got a chance this past weekend – http://flic.kr/p/8gg4w4

I’m fairly pleased with the results but now I’m hooked and can’t wait to shoot some more! Thanks again for the great advice!

Cheers,
Ian Hyatt
Fernando Ortiz
on August 10th, 2010
52
You mention that ones needs to set the camera in continuous drive mode (in my camera(canon t2i)… cant enable both with a remote control)
Dan Newton
on August 11th, 2010
53
You can if you get the wired shutter release.