Comet Like Star Trails

April 25, 2012  •  11 Comments

UPDATE: Since I've written this Steven over at Star Circle Academy has created an Advanced Photoshop Action that automates this in a similar fashion. If you prefer to do it manually or want a little more control, read on.

I've seen a few very unique images recently that turned star trails into what almost look like a sky full of comets, yet none of them shared their methods. This really disappointed me as I firmly believe that sharing knowledge helps us all improve together as a group. So without further ado, here is my method.

First off the method for shooting is exactly the same as for making star trails, the key is to use the stacking method versus one long exposure. There is plenty of information out there so I won't be covering this; you can visit Steven's great site to learn more star trails and night photography
Next, we need to stack the images to create star trails, for this I recommend using Steven's Star Stacking Action, but we have to modify it slightly so we end up with the individual layers rather than a flattened image. After you install the actions, open the actions panel, expand Star Circle Academy Stacker, duplicate "Load and Stack in LIGHTEN Mode (Recommended)", in the copy of this delete the step 'Flatten Image'. Follow his instructions, the only change is when you are at the batch step you will select this copy of load and stack.
Now we have a bunch of layers that have their blending mode set to Lighten, I'm sure many of you have already figured out by now that all you need to do is change the opacity of each of these layers to be progressively more opaque. In my image I had 20 layers so I set each layer 5% apart; for example 95%, 90%, 85%, etc. This creates the trailing off that looks so cool. I've found that around (50) 30 second exposures looks very nice.
Finally to get the bright star with the spikes at the end of the trail I used the amazing plugin Star Spikes Pro which has an incredible amount of flexibility. I applied this only to the background layer (which I duplicated of course) I'm sure some won't like the spikes but I don't really care, this is art.
That's it! It's quite simple actually, the only thing that took a long time was cleaning out all the planes from different frames. I found that using layer masks and leaving all the layers on made this a lot simpler than trying to clean up each frame individually cloning because then you can see what effect it's having and you can be much less anal.
I hope this helps some of you out, and I want to see your results! I know I'll be putting this to good use in the near future as I plan to get out a lot more. Please feel free to re-share this and ask any questions.
UPDATE: Previously this image had the milky way moving with the stars, to create a static milky way I brought in one of the 30 second exposures, used select > color range on this layer and selected one of the stars, adjusted the fuzziness so just the stars were selected and made a layer mask from this selection


11.Mick Skelton(non-registered)
Thank you David , I appreciate it , On my blog are photos I been working on before I read this article . I will be using much of what you shown here in the near future. I have asked many people how they got some of their final pictures and it has been like trying to get government secrets . Where's Edward Snowden when you need him?

I wish there was a website where people shared their insight.

Thanks again
10.David Kingham(non-registered)
It does not work on a Mac unfortunately. The developer has some plans to create this, but could not give a timeline
Splendid tutorial! Thanks for the sharing.
Is the StarSpikes Pro compatible with Mac CS6?
8.David Kingham
I've updated this post to include some new information and fix some broken links
hi there
i was searchign on the internet how to create those droplets kind of startrails …
ive been shooting ST for like few months now n im still a newbie at this art but this thing fascinates me alooot
well the link u shared for stacking
is not opening at my end …
i ve tried other websites also but cant find any proper stacking procedure …
it would be nice if u make a small tutorial or a video on vimeo
ill be greatful
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