Tag: telescope

Today an amateur astronomy icon passed away.  John Dobson popularized the very simple design of telescope that came to bear his name, the Dobsonian.  As a Vedantan monk John possessed few material means, pursuing a passion for telescope building in the monastery garden shed he designed a telescope that could be built from whatever scrap parts he could scavenge.  He could often be found around San Fransisco showing the wonders of the night sky to anyone who would look through one of his telescopes.   His infectious enthusiasm for astronomy led him to help co-found the San Francisco Sidewalk Astronomers.

The Dobsonian is a telescope that is characterized by an extraordinary simple and robust design. Made of plywood and other hardware store parts, there was nothing in the design that could not be built by hand.

The optical layout is a standard Newtonian design with the eyepiece at the front of the telescope.  This allows the heavy primary mirror to be located quite close to the ground.  The entire telescope rotates on a simple lazy-suzan azimuth bearing made of plywood, formica and teflon blocks.  A simple set of trunnions allows the telescope to be raised and lowered in elevation.

The Dob brought large aperture astronomy into reach of thousands of backyard observers.  Anyone with a modicum of skill could build a Dob in a garage with simple hand tools.  Commercial designs soon appeared at very affordable prices.

Amateur telescope makers have built upon John’s ideas, creating elegant designs that far surpass those simple telescopes made from scrap. Aircraft grade plywood, machined aluminum frames, carbon fiber and computerized controls are common in modern Dobsonians. The design can be scaled up, Dobsonians are sometimes enormous, with telescopes of 30 or 40 inches aperture seen at many star parties. At OSP last year I setup next to a 40″ built by Chris Fuld, a monster telescope built by hand.

John spent much of his later life touring wherever dark skies, telescopes and people could be found. This often included national parks and regional star parties. I met John a few times across the years, at Grand Canyon Star Party and at an evening observing session at Starizona, an astronomy shop in Tucson. His signature graces the secondary cage of my 18″ f/4.5 Dobsonian, Deep Violet, beside the signature of David Levy.

John was also a proponent of a decidedly non-standard cosmology, believing that the Big-Bang model had fatal flaws.  His alternate ideas make…  Uh?  Interesting reading.  He describes a recycling steady state cosmos heavily influenced by the teachings of eastern religions and mystical thought.

John Dobson died today, 15 January 2014 at the age of 98 in Burbank, California.  John leaves behind a son, many friends, and a community indebted by his contributions to amateur astronomy.  My friend Dean Ketelsen knew John far better than I did, I suggest you read his notes on his passing.

I spent a few moments and put all of the photos of dobsonian telescopes that have appeared here on Darker View into a gallery.  The photos are just a little sliver of what John Dobson meant to amateur astronomy…