Processing startrails and custom PS script for comet-like trails

[SDX]

Startrails are cool.
I love startrails, seeing the final result after the stacking for the first time surprises me every time.
After having done a few in the past, I've looked into a few techniques in the area of startrail-shooting. Something I was interested in were comet-like trails.
However, I was not able to find a free tool that could help me. I usually use startrail.exe (google it), but it doesn't have such a feature. I found a script for Photoshop on the internet for $17, which, in my eyes, is a bit too expensive. So I wrote one myself. This, however, means, that you'll have to do the stacking in PS. Photoshop is not the optimal application for this stuff, since the process consumes a incredible amount of memory and is very slow. But hey, it works!

For those who are not familiar with the workflow, here a brief walkthrough.
First: take pictures! MLs intervalometer will be a great help here. Go to Manual-Mode. Disable any kind of oncamera noise reduction, set it to burst mode, set ISO to something between 400 and 1600 (depending on your model). Aperture wide open and exposuretime between 15 seconds and 1 minute. MLs bulbtimer will be a great help. Find yourself an interesting location, make sure the lens wont get fogged and start intervalometer in "take pics like crazy"-mode. Now, wait.
Depending on the focal length and the length of the trails you want, you'll have to wait 20 minutes to many hours. I usually shoot with 10 to 14 mm (on crop) and 40 minutes to 1.5 hours. Shooting RAW is not necessary unless you want to adjust the whitebalance allot afterwards.

Next: Since I want to use my comet-script I'll use PS. Take my script and throw it into PSs scriptfolder ("C:\Program Files\Adobe\Adobe Photoshop\Presets\Scripts"). Start PS.
Now, the usual procedure. First off, load files into Stack.

Now.. wait. This might take quite a while.
When Photoshop has finished loading all pictures, select all layers and set blendmode to lighten.

Now you have a traditional startrail. If you only want those, save it and be happy. Don't grade it this state. Save it as a jpg or tif (choose "discard layers") and reopen it if you want to.
But we are not going to do that, since we want comets.
Go into Scripts and choose "Apply Opacity Gradient".

It'll ask you in which direction the comets should go. Now it will do a bit magic and you are done. Save it as described above.

Here is the final result:


The script is incredibly simple, just a few lines. You can download it here. If you are interested in how it works, open it! Scripting for Photoshop is fun.

For inspiration, check out the Startrail group on Flickr. Lots and lots of work from talented people. I'm on Flickr as well.

Looking forward to see your results.
Have fun!

[SDX]

Spend the night at the local beach, shooting startrails in order to test the comet script.
Here are the first results. I'm quite happy with it.

[dexMilano]

Hello,
I did my startrail with ML last Xmas on mountain.
I've made also a movie of it.

About the script, I'm working on linux where GIMP is the master.
I've found a script just for it
gimp-startrail-compositor
Perfect for me

I've a question: why you're talking about comet?
Shooting to a comet requires an active tripod to follow it.
If you do a startrail you'll see a large strip.

maybe I miss something.
Is there a comet in your picture?

dex

[scrax]

...Something I was interested in were comet-like trails...

All what this topic is about is to shoot star trail and use the script to make them "comet like"

[dexMilano]

Sorry...


However,
considering that this year we will meet 2 of the most beautiful comet ever, aslo using ML for capturing comets could be interesting too..
;-)

dex

[scrax]

Sorry...


However,
considering that this year we will meet 2 of the most beautiful comet ever, aslo using ML for capturing comets could be interesting too..
;-)

dex

Yeah, we should make a "competition" just to share the pix and have fun

From where their will be visible and when?

[dexMilano]

I can only suggest

http://www.skyandtelescope.com/observing/ataglance?pos=left
and neighbours

dex

[babarasghar]

thanks alot brother for sharing such an amazing and simple script ... people sell same thing for lots of money ...
have u tried using Photoshop "Actions" ... i saw david kingham tutorial regarding it ...
i did such a startrail also ...
plz have a look

http://www.magiclantern.fm/forum/index.php?topic=4623.msg26963#new