First off, I want to give a big shout out to anyone who has had a hand in creating Kstars/Ekos. I absolutely love imaging with this application. I have run into a few bugs, but the forum users have been a big help getting each one resolved.
As a macOS user who had issues getting astrometry.net working offline, once I finally did, I wanted to share the steps that worked for me. I did this with a fresh wipe and reinstall of macOS Catalina 10.15.5 . The following steps begin after I installed Kstars. This method utilizes Sextractor, not python.
***A side note: ASTAP works for me like 50% of the time, and that is why I kept working on getting astrometry.net to work offline. Sometimes ASTAP simply times out while solving without logging any specific reason.
2. Install astrometry.net via homebrew using terminal
⁃ brew install astrometry-net
3. Set index folder location in Ekos solver options
⁃ You can choose any location you want
4. Download index files
⁃ In the Index Files tab set the index file location to the the folder you selected in step 3.
⁃ Check the index files you want to download. I downloaded all of them
***Important: It confused me my first time around, but this time I did not follow any of the instruction in the README link within index files tab. There are links withing that page that will take you to instructions that no longer function in the latest versions of macOS. I simply just download all of the index files available. I believe the more index files you have can cause the solving process to run a little longer, but the entire process is so quick once you get it working offline that it’s really not a problem.
5. Confirm the location of the newly installed astrometry.cfg file.
⁃ Mine matches the locations below.
6. Make sure the following boxes are checked in solver options/astrometry.net.
⁃ Use Sextractor not python
⁃ Make sure python remains UNchecked.
7. Change the following three settings in solver options/astrometry.net
⁃ You’ll need to UNcheck these three boxes, but still fill them in. This is a little confusing too, but Unchecking them simply means you are providing the locations instead of using the default locations.
8. Using a tool like BBedit, open the astrometry.cfg file and change the index file path to the location you chose to download them too in step 3. Don’t forget to save the file.
Now you should be able to change the Solver to Astro.net, Offline and solve almost instantaneously.