Having a camera based device with no image display is an interesting challenge. My latest extension seems to solve most issues.
It displays a patch of 32x32 pixels around the brightest star in the image, its max value, the number of stars found, and the current exposure value, plus a PSF of the star as a plot.
As long as you arent too far away from focus, this works really well in tweaking focus and adjusting exposure to get a reliable capture of stars (as determined by the Tetra3 centroid extraction)
The OLED has no greyscale so the star image is very crude, but does help. The PSF and star count are key.
I want to add it to my standard eFinder, but I have to send the frame down the USB from Pi5 to the handbox Pico. More learning required!