14.7" f/2.9 Wide-Field Telescope
My smaller telescope. Constructed and modified between December 2019 and January 2022, with updates still ongoing, this instrument is designed to do everything: wide-field vistas, sharp planetary views, and deep views of galaxies and globular clusters. The primary mirror is 0.8" thick quartz and made by Nova Optical. The secondary is a 3.1" Antares unit, accurate to 1/20 wave.
The whole telescope is just 45 pounds, and fits in my passenger seat if I need it to. It can be assembled in as little as five minutes. Before I moved to Tucson it also had an equatorial platform for motorized, hands-free tracking - something all my other scopes lack. With a 21mm Ethos eyepiece, I can get a 1.7-degree true field of view - 3.5 full Moons across! The scope is currently on its 20th revision.
Me at the Portland XIII Alt-Az Workshop talking about the scope
Read below if you're interested in learning more about the design process of the scope.
Design & Build
The 14.7" scope was originally conceived at the Portland XII Alt-Az Workshop in August 2019. I wanted a larger and more convenient telescope than the 10" f/3 Newtonian, and considered a number of options ranging from 13 to 18 inches in aperture. In the end I got a good quote from Nova Optical for a 14.7" f/2.9 so that's what I went with.
The scope went through a number of different iterations.
DPAC image of the primary mirror
Mark I - maple/aluminum A-frame tube, scrapped due to difficulty with gluing up panels
Mark II - 1/2" plywood with nesting UTA, scrapped due to baffling issues and lack of rigidity to mirror box
Mark III - Sonotube, scrapped due to bulk
Mark IV-VI - Various weird and wacky designs that were scrapped in development
Mark VII - The one that got me famous on Reddit. Lots of issues (balance among them). Used parts from scrapped 12" Dob, Aurora Precision mirror cell, KineOptics HC-2 helical focuser, drum shell for upper tube assembly.
Mark VIII-IX - Various slight upgrades to Mark VII (pole darkening, counterweights)
Mark X/XI - Complete redesign/rebuild with larger altitude bearings, shorter mirror box/UTA, new truss brackets. Mark XI added truss pole wrapping (fake CF vinyl)
The completed Mark XI
Gluing up bearing laminate next to the completed mirror box
The new homemade truss connectors.
Assembling the OTA
Mark XII/XIII - New mirror cell edge supports (rollers) - thanks Nathan! Also added a shroud, handle, and feet below the mirror box so it can safely be set on the ground.
Mark XIV - Moonlite focuser, light baffle above UTA, hand knobs for pole attachment, improved cable management for dew heaters/controller, corner braces on mirror box. Block II added magnets for attaching UTA to mirror box securely during transport. Block III added even better cable management.
Mark XV - New rocker box, baffle below mirror box. Scope can now be carried in one piece. Block II added the EQ platform from Ed Jones which I painted and assembled myself. It replaces the ground board.
Mark XVIII - Better upper pole connectors, rocker improvements, new mirror supports. Mark XIX added glow in the dark tape and some improvements to the spider.
Mark XX: Replaced EQ platform with legs for move to Tucson. Improved power and cable management. Oh, and more stickers!