Re: ATMing in the September Sky & Telescope

["Guy F. Brandenburg" <guyfbran@erols.com>]

> <<Back in 1994, Clyde attended Stellafane. He brought with him his trailer
> and farm tractor to remove the 20" Mersiene from the trailer. We thought it
> was novel at the time; but given today's larger DOBs, 40" and up, it makes a
> lot of sense. I think we are going to see many more Mersienes DOBs in the
> near future. Sure beats climbing the 8-10 foot ladder. The design seems
> simple. The only question I have is how to optimize it for a specific size
> mirror and refractor. Maybe Michael Pantratz could comment on the design
> aspect optimization.>>
>
> The Mersenne telescope uses two confocal paraboloids of the same F/ratio. In
> this configuration, the secondary colimates the light cone from the primary,
> and eliminates the inherent coma, astig, and field
> curvature. The colimated beam is the re-imaged by a refractor in Clyde's
> incarnation. One can actually see through a Mersenne scope without an
> eyepiece.

I saw that telescope at Stellafane that year, my only visit to the place. With
all due respect to the enormous amount of work, energy, money, time, and
material put into that Mersenne scope, and knowing that I have only done a 6"
and an 8", both DobNewts, I frankly didn't think it gave views of the heavens
that were all that wonderful. There was another humongous scope there that
evening, dubbed the "yard scope" because the mirror was 36" across, and the
views it gave were simply stupendous. I was one of the last people to look
through it at the Veil nebula in Cygnus at about 3:30 or so in the morning --
OOOMYGOD -- pink lace curtains over a pitch-black field with pin-point jewels
of white and blue -- Now that was fantastic!!!

I liked the views that night from my little cheesy 8" homemade piece'o'crap
better that what I saw from most of the other scopes that night. Not that I
could ever hope to match their engineering knowledge and skills. But that's
not necessarily the most important thing.

Guy Brandenburg