12.5 Inch Dobsonian Telescope | Carbon Fiber | V2

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UPDATE: New version 2 of the altitude gear system now available. 
- Now using module 1.25 gears instead of 1. Larger, stronger, more printable gear teeth.
- New design for the large altitude gears with better part split and rejoining for a more seamless gear profile.
- New roller gear mechanical design to be stronger and more accurate. 
- Updated altitude motor mount and drive gear to accommodate these other changes. 

This is a 12 (or 12.5 inch), f/5 Dobsonian style, Newtonian reflector telescope. It is designed to be mostly 3D printed, with additional CNC machined flat carbon fiber sheet parts and carbon fiber tubes. It also disassembles for transport. 

• You will need a mirror set. I found a used 12.5 inch, f/5 set on the Cloudy Nights Classifieds. Agena Astro sells a 12 inch f/5 set that will also be adequate. The primary mirror needs to be thin, around 1 inch. 
• 3D Printed in 3DXTech CarbonX ezPC
• Carbon Fiber tubes sourced from eBay sizes:
• 25x21mm
• 20x17mm
• 17x13mm
• 15x12mm
• Carbon Fiber sheet parts CNC – AliExpress Vendor
• Turntable bearing for azimuth – AliExpress Vendor
• Total Cost ~ $2000. More then a pre-made budget option, but much cheaper then a premium option.
• Bearings and Teflon (or UHMW) blocks used for altitude axis motion to provide smooth, damped motion
• Additional Teflon (UHMW) dampers on the azimuth bearing (not shown in model.)

It is intended as a manual, “push-to” telescope but stepper motors can be added for “go-to” functionality with an OnStep controller. The motors can be engaged/disengaged to switch between drive modes. 

A bit of manual tuning will be required to get the motion smooth without binding but it does work quite well once dialed in. 

The views are incredible! 

Additional documentation and build pictures on my web site - https://designbydave.net/3d-printed-carbon-fiber-12-5-inch-dobsonian-telescope/