T2 Filter Changer (Artesky compatible)

##T2 Filter Changer (Artesky compatible)

* optimalized for 17.5mm or 12.5mm camera backfokus, final backfokus is 55mm


###BOM

* M42mm - M42mm male-to-male coupling ring adapte
* 10mm M42 extension tube for 17.5mm camera backfokus
* 15mm M42 extension tube for 12.5mm camera backfokus
* Neodymium Disc magnet 5mm dia x 1mm


* [More filter slider](https://www.thingiverse.com/thing:4150202)

###UPDATE
2020-11-24 Add support for [EOS Lens Adapter for EFW](https://astronomy-imaging-camera.com/product/new-eos-lens-adapter-for-efw) 19-20mm thickness.