Home Built 8" f/6.8 Newtonian on Dobson mount

8 Dobson Newtonian
This telescope represents my first completed ATM project.  I ground, polished, and figured the mirror myself and constructed the entire telescope except for the focuser and diagonal.  As such, this simple optical aid represents the culmination of a dream I hatched around 1970: to build my own telescope.  For the full, grit by grit saga of its construction, go here.

There's a complete construction log in the ATM section of my pages, but to make a long story short, I started gathering materials and tools in February, 1999, and despite basement floods, changing jobs and schedules from swing shift to early mornings, and the usual trials and tribulations of modern life, I was able to complete the scope as you see it here in time to transport it from Seattle to Socorro, New Mexico for the Enchanted Skies Star Party in October, 1999.  At that gathering, I was able to compare my views under dark skies against those provided by various commercial Schmidt-Cassegrain and Maksutov-Cassegrain telescopes costing in excess of $2000 (not including their computer controls).  Not only were my views nearly equal to those of 10" SCTs, but on several occasions I was able to locate familiar objects and place them in my eyepiece faster than those with control paddles could slew their motorized mounts to the same object.

That first full weekend of dark skies saw me bag the dim M1 planetary nebula, catch the diffuse Magnitude 9.5 Comet 1999 H1 Lee (working only from star charts), find both the Lagoon and Trifid nebulae without prior knowledge of their location, and be able to see M31 spread across an entire field of well over a degree.

Since then, I've seen marvelous views of the Moon, M42, Jupiter and Saturn.  I've taken pictures of the Moon through the eyepiece that are posted elsewhere on these pages.  While no ATM project is ever really finished, and there are some fairly immediate improvements I need to make to this telescope (an end ring for the front end of the tube to keep it round, and improved azimuth bearing are high on the list), it's very usable as is -- and I can (just) transport it in a 1989 Hyundai Sonata by using the pass throughs from the trunk into the back seat.

Below you'll see some of the details of this scope, including the mirror cell, wire spider tensioners (made from guitar machine heads), and the spider itself.

Here you see part of the mirror cell:

Here are two views of the spider tensioners: Using guitar strings for the wire, the idea of using machine heads for tensioners was obvious.

Here's a front view of the scope, showing the spider and diagonal mount, as well as the focuser (and the out of round tube).

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If you have comments or suggestions, email me at silent1@ix.netcom.com