Hello,
First of all - big thanks to Hy for adding this feature to KStars!
Very helpful.

I added a bunch of my images as Image Overlays. Worked very well.
But is there an easy way to reorder the overlays?
I.e. to put one to the top without deleting and re-adding?
(I have quite a few wide-field images and often narrow-field images are hidden behind).

Thanks!

Perhaps alphabetically? E.g. prefix your wide field filenames with “wide” or something like that, and then restart kstars.
Hy

Good idea, Hy!
I wish I did this when I started.
I have quite a bit of overlays and now would have to re-plate-solve too many.
Not a big deal. I can live with the way it is.

Thanks!

As I recall, you can just put the files in the directory and then select multiple rows (perhaps by selecting the one at the top then shift-clicking one way below) and then just click solve and it will do as many as it can. It may take a while, but you can take a break and do something else. Probably setting the default arcseconds/pixel right for that set of images and perhaps some reasonable timeout would be a good idea. Then if a few don't solve you can either deal with them by putting in the roughly right position or just skipping them.

Hy

Thank you for the advice, Hy!
Maybe I'll rebuild my overlays someday.

Hy,
I rearranged some of my overlays.
This wasn't as hard as I thought it would be.

When I started to use the overlays, the plate-solving was a bit unreliable and I had to provide an approximate position.
So I kept doing that.
It turned out, that now plate-solving works much more reliably in the blind mode (i.e. without providing the approximate position).
Great!

Question:
I have now around 80 overlays sized 500KB on average.
I don't notice any KStars slowdown.
Can I add 80 more? 800 more?

Thanks!

Max,

I don't know why the plate solving would be more reliable. Perhaps you're using the accurate scale now and you weren't before?

Re the number of images the overlays are kept in memory. (A less lazy coder than me might have done some on-demand loading, perhaps I'll do that in the future someday, but probably not really soon.) So, whatever virtual memory the images take will be your limit. You could experiment by adding 10 more and seeing the increase in virtual memory for the kstars process. Then add 10 more and verify you have a similar increase. Then you could decide--let us know.

Note: The file size won't tell you the answer--jpeg compression won't be taken advantage of. The full image stored in memory in a QImage doc.qt.io/qt-6/qimage.html (e.g. so the memory use will likely be something like width * height * bytes-per-channel * # channels. That is, if all your images are RGB and the same resolution then they'd all take the same amount of memory. If you're curious, you can see the code that loads the images here:
invent.kde.org/education/kstars/-/blob/m...?ref_type=heads#L448

Hy

Hy,
I checked the memory usage (in Windows' Task Manager).
Before I started KStars my memory usage was 10.5GB.
After I started KStars - memory usage went up to 11.2GB. Not much.
Enabling/disabling overlays didn't make any difference.

Just reporting.
Thanks!

Enabling/disabling overlays won't have any effect. The images are all loaded on startup regardless if they're currently set to display.

Memory use and Virtual Memory are two different things . I'm not familiar with MS Windows. This page says look at "committed pages":
superuser.com/questions/1489609/how-to-f...-used-by-the-process

Hy

Hy,
Good information.
Thank you very much!

I too would like to be able to re-order the overlay images. Let me see if I can work on an MR at some point. Found out from ChatGPT that it's fairly easy to set drag drop up in `QListView`, might be similar in `QTableView` or whatever the feature uses.