fixes: real sky tested

focus_utils.py

@@ -335,7 +335,7 @@ def focussingSequence(
         ret_val["ret_code"] = -1
         return ret_val
 
-    N = 7
+    N = 5
 
     if len(focus_range) > 2:
         if np.isclose(focus_range[2], 0):
@@ -421,7 +421,7 @@ def focussingSequence(
         # filename = "{}_{:04d}{}".format(fname, i_foc, file_ext)
         # full_filename = str(pt.Path.joinpath(dir, pt.Path(filename)))
 
-        full_filename = str(rname.with_stem("{}_{:04d}", rname.stem, i_foc))
+        full_filename = str(rname.with_stem("{}_{:04d}".format(rname.stem, i_foc)))
 
         print(log_ident, file=log_output, end="")
         print(