Using KStars and images that I took with my camera's 150 degree lens, I plotted my Artificial Horizon. (Where's my chainsaw? Just kidding!)

This is probably not the best forum to bring up issues with KStars so please excuse me. I was wondering what I can do to tell KStars to reverse colors? I would like the region that is colored red to be black and the region that is black to be colored red. I am attaching the altaz points that I am using.

Thank you!

Most of the colors can be changed in KStars Settings --> Color Scheme. Try to experiment with different colors until you get the desired results.

@knro: Correct me if I am wrong, but I think the OP asks about a different thing. The Artificial Horizon expects to get polygons of the blocking objects, but OP has a very small FOV because of the trees. Basically, the red area on the screenshot is the visible sky and all the rest are trees. I think he wants KStars to "invert" the regions, having the defined polygon the FOV and draw everything else red.

Ah okay... well, there is no way to do this now... not sure how difficult it is to invert the polygon.

I was looking at the issue as I'm in the same weird situation. The best way I found was to compute small columns from the csv table using properly offset RA as base, up to the intersection with the fov boundary. Then multiple polygons can be imported in kstars, which is easier to handle without rage quitting But my implementation is far from effective. Having a wide angle lens is certainly the best way to obtain preliminary data.

Thank you, everyone. TallFurryMan has got me thinking...

Where does KStars keep the artificial horizon user input file(s)? It would be great if I could experiment and edit this in a text editor. Thanks!

Check this, that's what got me started: www.ncbi.nlm.nih.gov/pmc/articles/PMC4242535/
It's not exactly the same field of application, but it has interesting points of view.

Edit: ummm probably not the one I was using for hemisphere partitioning actually, I'll look that up in my bookmarks.

Please excuse my crude drawing. This is how I propose to modify the polygon by keeping my interior points but then adding points around the horizon.

Cut the donut in multiple pieces using the north pole as center, and slices segments starting at each of your points. You will get multiple quads that you can import as obstacles. There will be seams, but they are fixable by overlapping the pieces. The other problem is to align your picture towards the north pole.

@knro, concerning the artificial horizon editor:

1. Why have a rule saying that First and Last points must be on the horizon? If there is a UFO blocking my view why do I have to anchor it to the horizon?

2. There is a peculiar tendency for the software to want to "auto-complete" my polygon. I can understand that this can be helpful when choosing the input method that allows me to point-and-click using the Sky Map. But when I choose to use numerical entry via the grid control it is quite annoying and prevents me from building the polygon I want.

3. Are the region files text-based that I can edit outside of KStars or is the data stored in binary?

Thank you.

I finally had success (see attachment).

Before discovering KStars, I was a C2A / OccultWatcher user. Today I returned to C2A and followed their directions to quickly compose my horizon in a single region file. I took what I learned and tried to do the same in KStars but unfortunately it will not properly handle a 360 degree horizon definition in a single region. So I broke it down into four quadrants and finally had success.

The data is stored in an SQLite file. It was a quick task I've done last year to implement this feature. If anyone can submit a patch to extend its functionality, they are most welcome!