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.
Awesome info. Also, super cool image with the Mac mini on top. I would love to do that, but am currently using a Raspberry Pi and remote imaging on my desktop Mac inside the house. I really hope Apple makes an Apple TV sized device as a new Mac mini with their custom chips. I would buy a bunch of those for different applications including imaging.
Have a look at the fourth image (the one with the overview of the index files) which also contains the sizes involved. By the way, you only need the ones with the green check marks. The ones with the red crosses and triangles are not needed for successful plate solving.
Wouter van Reeven
ASI6200MM and 7 slot 2" filter wheel with a SkyWatcher Esprit 80 ED on a SkyWatcher HEQ5-Pro
ASI1600MM-Pro Cooled and 5 slot 1.25" filter wheel with an 8" TS Ritchey-Chrétien on a SkyWatcher EQ6-R
The entire index file library is about 32GB. The Mac mini has a 512GB SSD, so it's completely worth it for me to have all of them downloaded. If you are using a RPi device with a small flash drive, downloading all of them might not be an option.
With Sextractor & astrometry.net you have a powerful solver.
Out of curiosity and product improvement I like to investigate why ASTAP is not working for you. What binning did you set in Solver settings? See below:
1) For ASTAP you shouldn't bin too much. The resulting image after binning should be 1280x960 pixels or more. So the binning typically should be set at 2x2 in above menu and in the ASTAP menu at 0=auto.
2) An other reason for unreliable solving could be a FOV error. Your screenshots indicated 25.5' x 20.4'. If you load an image in the GUI of ASTAP, is the same FOV indicated in the statusbar of ASTAP?
3) If the exposure time for the image to solve is long it could be that the G18 star database up to magnitude 18 is required rather then the G17. (remove the G17 to force use of the G18)
These causes of poor solving performance can be checked by inspecting the FITS image in /tmp created by EKOS.
In the latest versions of ASTAP some improvements have been added for more reliable solving. Blind solving speed has been increased with about 25% in the latest version 0.9.382.
The ASI533 camera your using has a native resolution of 3008x3008 pixels which would result in a square FOV. But the manual is also speaking of 1920x1080 pixel mode. So the question is which binning mode is used?