Saint Petersburg Astronomy Club - Mirror Lab


Science Center of Pinellas
7701 22nd Ave N
Saint Petersburg, FL 33710

We're available from 12 Noon to 4PM each Saturday

Our Founder

Paul McNabb founded the mirror lab in 1997 in order to create the best amateur telecopes possible. Inch for inch our mirrors surpass store bought or commercial grade scopes.

04/12/2012 more


  • Ralph Craig - Lab Instructor
  • Allen Maroney - Lab Instructor
  • Ron Jones - The Figurer
  • Mike Davis - Casts Mirrors
  • Dimitri - Support


  • James Lerch - Robo Foucault
  • Matt Terry
  • Charlie Mullen
  • Bruce Kazcmarik
  • Keevy McAlavy

In Memorium

  • Irv Nadelhaft
  • Lenny Remetta

04/12/2012 more


Where the 19th Century Art of Mirror Making Meets the 21st Century

The Saint Petersburg Mirror Lab is a small band of dedicated mirror grinders and telescope makers living in the Tampa Bay area of Florida. We offer a mirror making class for interested persons. We strive to create the best mirrors our home brew technology can muster. This includes robotic foucault testing and laser interferometry.

  Rough mirror made smooth
Steve Maiaroto brought in an 8 inch piece of glass that he polished and figured years ago. We put it
on the Foucault machine to measured the surface and it came out to sixth wave, which is better than
our minimum requirement of quarter wave. Unfortunately, we detected a polishing issue that needed
addressing. Periodic marks were rubbed into the glass as seen in image A, which can contribute to
scattering and distortion. The most likely causes for this issue are aggressive rubbing, lack of
randomness or a hard pitch lap. We poured a new pitch lap and decide on the best stroke to work out
the pattern without affecting the shape. It took about 2.5 hours of rubbing to get the results you
see in image B.

  Grinders in the Shade
Brad, Richard and Mike(l to r) grinding and Paul in the background prepping a tube for black paint.

  Paul Pouring Hydrostone
Paul is creating the base for a polishing tool for Richard's BVC mirror. We expect that the BVC
will move to polishing in the next week or two.

  Richard's BVC Mirror
Richard, Brad and Ralph inspecting Richard's BVC mirror. It needed a little work getting the curve
all the way out to the edge which was resolved the following week.

  Soldering and Grinding
Steve and Paul (l to r foreground) are soldering a dew heater controller. Brad and Ron are working
on Brad's 14 inch mirror.

  Bill and Ralph Cut A Tube
Bill (left) and Ralph cut a 12 foot long 12 inch tube to a more appropriate length for Bill's 10
inch f/5 mirror.

  Brad's Finished Telescope at the OBS
Brad finished remaking his telescope in time for the 2019 Orange Blossom Special (OBS) Star Party

  Mike's Mirror Grinding Demo
Mike shared his mirror grinding skills during a demo at the 2019 Orange Blossom Special Star Party.

  Ralph's 12 inch Dob at the OBS Telescope Walkabout
Ralph finished his 12 inch Dob just before the OBS star party. Here he is explaining its
construction during the telescope walkabout.

  Dew Heater Controllers
Mike (left) and Dave (right) are building a couple of dew heater controllers. Brad (center) already
built one and is assisting the projects.

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