Note, this is shared for reference, and is not an endorsement by Simulation Curriculum.
YOU are responsible for vetting security, malware, etc.
From here: https://github.com/BTMeeks/SkySafariHorizon
This little python script makes a boring image that is ment to be a used as a custom horizon in SkySafari, based on mesurements you make of your horizon obstructions. You can use this image as is, or you can use this for a base layer to align photgraphs or panorama of your horizon. When using this custom horizon, you have a truer picture of the sky at your site, and you can more accurately tell if a particular object is actually visible at your site.
It uses a CSV file that you prepare that describes your horizon. The first number on each line is the compass reading (azimuth), and the second number (after the comma) is the number of degrees (from 0 at the Earth's horizon) that describes the vertical obstruction of the horizon at that azimuth.
For example, if your horizon is at 20 degrees everywhere, except for a pesky mountain in the south that blocks the sky up to 45 degrees (and is 40 degrees wide at the base, you would use a CSV file like this:
160,20
180,45
200,20
There is a -m or --mobile option for the program; if on a device like an iPad or iPhone, the resulting file should be 2048x1024 pixels. Without the -m option, the program will produce a 4096x2048 file suitable for a computer. The file is a PNG file.
On my Mac, the file is at ./Library/Containers/com.simulationcurriculum.SkySafari6MacPro/Data/Library/Application Support/SkySafari 6 Pro/. Your mileage may vary.
On iOS, the file is in "On My iPhone", then "SkySafari Plus", "SkySafari Pro" etc.
Once the file is in the right place, go to SkySafari settings, the "Horizon & Sky". Select "as Panoramic Image" or "as Realistic Image", and your file name should be one of the choices, without the .png part.