star trails

[Jeremy Roussak]

Can you recommend good, preferably free or inexpensive, software for blending star trail photos? I have tried StarStax: it does a decent job on the trails but creates a bizarre cross-hatch, cheesecloth effect on the background sky. Ideally it should fill in gaps in the trails, but as I was using 1-minute exposures with a 2-second gap, they're virtually unnoticeable.

Thanks

Jeremy

[Bart_van_der_Wolf]

Can you recommend good, preferably free or inexpensive, software for blending star trail photos? I have tried StarStax: it does a decent job on the trails but creates a bizarre cross-hatch, cheesecloth effect on the background sky. Ideally it should fill in gaps in the trails, but as I was using 1-minute exposures with a 2-second gap, they're virtually unnoticeable.

Hi Jeremy,

For filling gaps, a Windows program called StarTracer does a good job, and it also allows to extend the tracks beyond what was recorded (requiring much less time in the field). StarStax uses a less elaborate method to blur in the gaps.

As for the blending itself, the success also depends on how clean the original images are, so maybe a little (high quality) denoising of the long exposures can help. NeatImage and Topaz Denoise do an excellent job of not killing all fine detail (stars). StarStax also allow to use multiple Darkframes to reduce long exposure time noise and hotpixels.
Not sure which method you used, but you can also try different blending modes in StarStax.

Cheers,
Bart

[Bob_B]

StarStax, Registax 6, and DeepSkyStacker are the programs I have used. They're freeware.

[Paul2660]

I feel the best way to blend is in Photoshop using a smart object and he stacking modes to blend.

To remove gaps which will always be there when you stack I use Star Tracer. 

Here is an article I wrote talking about my technique. 

http://photosofarkansas.com/2014/09/23/092314-using-stacking-for-better-night-photography-results/

Paul C

[Alan Smallbone]

Here is a place that sells some photoshop actions that work well, can handle and generate several different types of trails.

http://starcircleacademy.com/getstacking/

Alan


edit to change to a better link

[Jeremy Roussak]

Thanks for the replies. I should have said that I'm using a Mac, so the Windows applications are of limited value; I may in due course get a copy of Fusion or something like it, though, so I'll bear them in mind.

The cheesecloth effect seems to have been produced by noise. I opened the images as layers in PS and used "lighten" mode for all but the bottom of the stack, and it appeared just as it had done with StarTrax. Then I applied some pretty aggressive noise reduction in LR and tried again: no cheesecloth. Rather odd.

Jeremy

[Bob_B]

This may be of interest: http://www.picturecorrect.com/tips/star-trail-photography-tips/