This telescope is the second revision of my 3D printed low cost Newtonian Reflector. I took everything I learned from the previous build and the meantime to simplify the part list, lower the cost, increase modularity, increase ease of use, and make it pretty.
The new features include:
- Picatinny Rails for mounting optics and other accessories
- A new focusing mechanism with better tolerances and dual rack screws.
- Focusing mechanism is now a separate mount so it can be swapped for other devices, ex. camera
- Secondary mirror spider now features curved spokes, this significantly reduces diffraction spikes as per 2018 James Harvey et al…
- A secondary mirror cover which screws on
- A primary mirror cover which magnetically attaches, and can also magnetize to the back of the scope when in use, the following contain embedded magnets:
- PM Lid (3x)
- PM Cap (6x)
- PM Kine A (1x)
- Kinematic screws are now pop in ellipsoid joints.
- Knurling on everything
- Better CF tube covers, which are press fit
- A universal tripod mount, uses a heat set 1/4”-20 threaded insert
- Art! The primary and secondary mounts have a wrapped starscape with some little drawings
- A better fastening system for mounts, the following contain embedded 1/4″-20 nuts:
- PM Mount (4x)
- TM A (2x)
- SD-PM Clamp (4x)
This means the final material list is as follows:
| Name / Links | $ | Notes |
| PLA Filament (less than 1kg) | $15 | I’m sure you could use a fancier filament, but I don’t think it would be worthwhile. |
| 1m Carbon Fiber Tube 25mm | $38 | The basis of the build, be careful of the ends as they can give splinters (that’s why there’s caps). |
| Primary (114mm OD +900mm f) & Secondary (45°, 25mm OD) Mirror | $20 | Pretty standard kit, you can find alternative sellers online if need be. |
| Objective Lenses | $14 | Cheapest I could find on amazon, more money = better results. |
| 8x 1-1/2″ 1/4″-20 Bolts | $9 | These are for mounting the Primary and Secondary modules. |
| 2x 5/8″ 1/4″-20 Bolts | $12 | These are for mounting the tripod module. |
| 10x 1/4″-20 Nuts | $9 | These are embedded within the prints. |
| Red Dot Sight | $23 | I love the red dot sight, it makes it really easy to line up the scope with stars, planets, etc… |
| Collimation Tool | $26 | This aligns the optical axis and is key to getting high quality results. |
| 9x 6x2mm Magnets | $8 | These are embedded within the 3D prints for ease of use. |
All in all around ~$140 though MVP is ~$80
This is not the most competitive figure and requires you to already have a tripod, however it is within the price range of your standard 144mm telescope and makes a fun personal project.
There are some considerations to be made.
- This telescope will fit on a standard 180x180x…mm build plate but no smaller
- Print orientation is important, and many of these screws are being subjected to force, so print all screws at about a 15 degree angle
- There is not an ND filter on this scope! Objects in the sky will appear about 324x brighter, so the moon can be blinding. The wonders of a refractor telescope is (diffraction aside) the brightness can be controlled by how much of the mirror is covered
- This is an open concept scope, there are no side walls, if the area is lit consider adding some baffling to the scope
Using this telescope I have seen the moon, Jupiter, Saturn, and Venus all at pretty good fidelity for the price. Good luck building, and please contact me personally if you have any issues or questions.
