The Telescopes

The telescope and astronomy bug was set way back in college. As one of my senior projects, I was assigned to work on the university’s telescope which was in process of being motor driven. The mount (at the time) was a WWII gun mount, complete with alt/az chairs and hand cranks.

After saving for, and not really enjoying my $200 Tasco 4.5 Newtonian equatorial telescope, I updated the focuser (Orion basic rack and pinion 1.25) and bought new eyepieces. The supplied .965 eyepieces had small exit pupils and really hard to use. Also, I changed out the secondary mirror support using PVC fittings and a curved support to eliminate any diffraction spikes. The upgrade allowed viewing comet Shoemaker-Levy 9 ‘black-eyes’ on Jupiter from a apartment parking lot in Houston.   IMGP4821IMGP4823

The Tasco was fine to use and got regular usage (backyard, camp outs) but the aperture bug hit. It was time to go bigger. Researching telescope building and buying books (yes, there were books available in the dark ages), the design settled on a Dobsonian mount for a 8″ Newtonian.

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Using optics from Discovery Telescopes (8″ soda-lime, f/8 if I recall correctly), and more hardware from Orion, with concrete form tubes and plywood for the base. (It’s amazing to see the quality of wood that you could get from the box stores, comparing to today’s offerings – even plys, few voids, no warping). The secondary uses the same PVC arrangement but could not get the curved spider-vanes to support a larger mirror, so want with 3 vanes. Thinking, ‘3 is better than 4’ at the time, turned out to be a not-so-great moment. 4 vanes gets you 4 spikes – 3 vanes = 6 diffraction spikes.DSC05544

The TelRad was a real step-up in being able to really star-hop around, compared to the wimpy finder on the Tasco. The 9×50 RA finder hardly gets uncapped anymore.

 

 

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