Star Trail Stacker v2.5.1
This is a Photoshop JSX script designed to stack sequential frames(subs) taken of the starry night sky in order to create a continuous Star Trail image without the gaps that are naturally produced via interval time between frames or by the writing time to the camera's storage media.
This release fixes a bug introduced in v2.5.0 & updates the script to run without version nag in Photoshop CC 2017.
Tested in Photoshop CC 2017 with Camera RAW

Before installation of this update, navigate to your Photoshop's 'Preset > Scripts' directory & completely delete the folder named Star Trail Stacker.
Now simply unzip this download & copy the folder 'Star Trail Stacker' in it's entirety & paste it in to your Photoshop's version 'Preset > Scripts' directory,
example (C:\Program Files\Adobe\Adobe Photoshop CC 2017\Presets\Scripts) for Windows 64Bit version of Photoshop CC 2017.

If you have updated your Photoshop version & had Star Trail Stacker installed in the previous version of Photoshop and now it is no longer showing in the 'Scripts' menu, simply:
Before uninstalling the previous Photoshop version, locate the folder 'Star Trail Stacker' in the previous versions 'Preset > Scripts' directory then copy & paste it into the new Photoshop versions 'Preset > Scripts' directory.

This is an unfortunate implementation route that Adobe decided to take with the introduction of CC 2015.5 where each new version of Photoshop is located within it's own directory but Scripts are not copied from the previous install to the new install.
They gave Plugins their own directory outside of the Photoshop install from CC 2015.5, allowing them to be accessed globally but they have not implemented the same system with the Scripts directory as yet.

There have been one or two users report that the script is not auto installing/updating via the Creative Cloud app post CC2015, this seems to be hit & miss and as yet I have been unable to track down a fault at this end but I suspect it is more than likely an issue at Adobe's end.
My suspicions are borne out somewhat as on the Adobe Add-ons product page:
the info states that the script is compatible for Photoshop version CS6 to CC2015. I have not restricted the script to the upper version of CC2015 & it is something that only Adobe can alter but the Add-ons site is fairly poorly maintained by Adobe & it takes an age for them to update things.

I have had a user report that running v2.5.0 of the script in Photoshop CC 2017 on a directory the first time completes without error but if the script is run more than once on the same directory, without making any changes to that directory in the mean time, an error about incompatible files gets thrown up. I have tried to replicate this error but am unable to, I would certainly appreciate any further feedback on this issue.
I have also had a user report that v2.5.0 of the script throws an error when attempting to run on a directory that contains RAW image files, namely Nikon NEF format from a D750, again I cannot replicate this error & would appreciate more input. The script does currently cover all RAW files & camera models in version of Camera RAW.

At the time of writing there have been over 20K downloads of this script since it's first iteration & over 2.5K of version 2.5.0 alone on the Adobe Add-ons site:
without the odd behaviour as above being reported, I am hoping that this is a one-off glitch somewhere and I am working with the user in an attempt to understand the problem.

For any further assistance please contact me via the Contact form on this website.
Example Image Output
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Star Trail [2016.05.05]
(222) downloads