I think the development of the eFInder is nearing its end! The transition to Skyfield to do the maths went well. I then decided to use a standard Raspberry PI 32bit OS with a fresh build of astrometry.net installed, rather than use Astroberry. This makes available some useful new features.
Producing a working local copy of astrometry.net isnt trivial I discovered, but thanks to Dustin via the user group I got there and can now reproduce the build quite easily.
This process led me to look at the capabilities of astrometry.net more closely and in particular the family of supporting programs. One of the most useful is the ability to directly obtain RA & Dec of any pixel in the image, not just the image centre. I re-wrote the offset calibration almost completely and the result is much more accurate and stable.
A very nice feature of the full build is the ability to annotate captured images with markers and labels for catalogue objects. The GUI control is now very comprehensive and here is an example screenshot
I’ve also switched to using a remote OLED display, rather than the LCD module mounted in the Raspberry Pi housing. The LCD got very sluggish at cold temperatures and wasnt very clear either. The OLED is very high contrast and perfect for dark adaptation. A 3m USB cable connects the display/control box to the Raspberry Pi. Full build instruction can be found here.
