APPM does look at the FITS header. The only thing I can think of is that there is another FITS header keyword that it is using. APPM doesn’t just pick numbers out of a hat! J

> Even so, you missed the most important point I was trying to make in the subsequent paragraph of

> my previous message. Which is: why I cannot solve a single image using the tool: "Test Solve Images

> in a folder" ? I'll repost the details here for conveniance (please see log extracts in my previous post)

I have solved entire folders of FITS images with APPM. For example, see the attached video I just created using ASTAP to solve images in a folder. That said, APPM’s plate solving is designed to work with FITS files that it creates or had created. It is not guaranteed to be compatible with all FITS files, nor does it need to be.

In the mean time, if you provide a link to your FITS file, I’ll take a look at it.

> I am aware of that too. Thing is, as said before, no window opens right after I click on the menu

> above... And there is nothing about that menu in the built-in help file / the link you provided... 🧐

Okay I see what you meant! That menu item was used for creating test images and should have been removed.  In fact the Test Solve Images in a folder option needs to be removed as well.

BTW, you can use the NASA Sky View camera to test APPM and ASTAP during the daytime or in cloudy weather.  The “Image Link Test” button is just to help confirm you have the appropriate plate solver and stellar databases installed.

-Ray