Prefer use together with any DSLR with JPG output.
By importing the images and perform the photo stacking steps without bringing a laptop.
The application will stack up all JPGs in the selected folder and save the resultant as the file name "result.jpg" or the name you choose in the same folder.
It requires large memory size for the apps to process 12-mega pixels images stacking.
Testing images is done by maximum images size from an EOS6D shooting with a microsd and processed by a Sony xperia Z handset. Time for stacking 600 photos approx. > 3000 seconds and may need 10% of the battery for the processing.
I make this apps for my trips as I would like to shoot some star trails photos but not to bring up a laptop as the camera was already a heavy stuff which take cost when traveling in plane. And I just think if there are guys would like to shoot for star trails considering to bring less equipments and share the star trails immediately after shooting just like me, so I share this apps.