Houdini 20mm Eyecup Thread Adapter

This is a threaded adapter to help solve the loose eyecup for the Houdini 20mm eyepiece that likes to fall off every time you remove the cover. It's similar to another I've made for the Baader Hyperion series that makes it thread on and off the top like on the Baader Morpheus line. There are two versions, one with a 1mm lip similar to the overhang provided by the default threads that holds tighter just by being a bit larger overall, and another wider one in case the original size isn't adequate. It also allows the option to glue the eyecup to the adapter without wrecking the threads on the eyepiece itself. This is what I've done with my Hyperion. Ideally there would be a different rubber eyecup that's the right size to fit eyepiece directly, but I have yet to find anything other than ordering the free replacement from Houdini that would be too hard for my comfort using TPU. This mod also allows the eyecup to roll down flat for those that need to get closer to the lens element. I suggest printing in PLA, my first attempt in PETG had too much stringing and wasn't necessary. The PLA threads on perfectly when printed with a 0.12mm layer height. It fits on better when the eyecup is stretched onto it first, then threaded on, otherwise it's a struggle to get the lip on the eyecup to seat nicely into the narrow gap, but this way it pinches slightly when threaded on and holds just that little bit better.