Telescope: 106mm f/8.5 refractor

thingiverse

This is a 106mm diameter, 900mm f.l. refractor, based on the following components: Objective lens: https://www.aliexpress.com/item/1005001797311188.html?spm=a2g0o.order_list.0.0.7c581802rSG52C Focuser: https://www.aliexpress.com/item/32952077276.html?spm=a2g0o.order_list.0.0.7c581802rSG52C UPDATE: The focuser I used is no longer available, according to the Aliexpress website. However, this item may be a suitable substitute: https://www.aliexpress.com/item/32952109020.html This is a Crayford focuser with the same 78mmX1mm metric thread. I don't know what the back focus would be with this design. It's more expensive than the focuser I used. but it does come with a 2" to 1.25" adapter, which I had to buy separately. It consists of the following 3D printed parts: Objective lens cell Objective lens retaining ring Dew shield OTA section 1 attaches to the lens cell with three #4 X 3/8" wood screws OTA section 2 mates to section 1 OTA section 3 mates to section 2 OTA section 4 mates to section 3 and threads onto the focuser with a 78mm X 1mm metric thread Mounting bar, 200mm, with 1/4" X 20tpi nut Mounting bar, 200mm, Vixen-style dovetail Mounting strap, bottom, 2 required. This attaches to the mounting bar with 4mm hardware Mounting strap, top, 2 required. This attaches to the bottom strap with 3mm hardware I've also included a male threaded ring that matches OTA section 4, to mask off the threads while painting. The sections and dew shield should be painted flat black inside. Prime first with white primer to avoid black paint seeping through the print. Make sure your paint is compatible with plastic. The OTA sections are glued together with epoxy. Make sure you mask off the glue surfaces. The 26mm eyepiece in the photo is not included. You can find that design here: https://www.thingiverse.com/thing:5347023 A user asked whether a previous design ( https://www.thingiverse.com/thing:5212087 ) has enough back focus for astrophotography. That design does not, but this design should have enough back focus for a Canon or Nikon DSLR if the focuser retaining ring is removed, and a T-ring adapter is used, such as this: https://explorescientificusa.com/products/vixen-telescope-60mm-ring-with-t-thread-adapter I don't own one of these, nor have I tried it out, so buy at your own risk. UPDATE: I've added an adapter with a 60mmX0.75mm metric thread for the focuser and a 42mmX0.75mm T-Ring thread on the other side. Print this at 0.12mm vertical resolution or better. The objective lens holder and retaining ring, and OTA section 4 (and matching mask) all have threads which are best printed at 0.12mm layer height. 0.16mm might work as well. Everything else can be printed at 0.2 or 0.24mm layer height. All parts are printed in PLA, white for the OTA and dew shield, and black for everything else