Charlie and Allen demonstrate
|
- Ever think of making your own mirror?
- Want the best possible images from your scope?
- St Pete Astronomy Club Mirror Lab can help.
|
Mirror Making Class
The Tampa Bay area isn't known for it's good clear skys. We have
clouds, rain, haze and humidity to deal with in addition to
light polution. As a result we have to make our mirrors
better.
For several years the Tampa Bay Mirror Lab has helped young and old
learn the art and science of newtonian reflector mirror making. We can
show you what we do and how easy it is for you to
start making your own optical masterpiece.
The mirror lab offers a year round mirror making class. First time
mirror grinders are now recommended to start with 10 inch blanks. (8inch
is still acceptable). First timers are also recommended to work towards a
focal ratio of f/6 as this is the easiest.
Course description:
Student will construct a ceramic tiled tool for grinding.
Basic grinding techniques to acheive spherical curve will be demonstrated.
The making of a pitch lap for polishing and figuring will done for each student.
How to perform the Foucault and Ronchi tests.
Guidance in the use of software to make Millies-Lacroix plots.
Class Price $100.00
Contact The Science Center of Pinellas County Inc.
7701 22nd Ave. North
727-384-0027
or Paul McNabb at 727-345-5713
Glossary of mirror making terms
Sagitta to Focal Length Calculator
Sagitta Calculation Sheet (pdf format)
Portable Grinding Table schematic (pdf format)
Inside Tube Paint Sprayer
(pdfs courtesy of Allen Maroney)
The Steps
Grinding Starting with 60 grit going all the
way to 5 micron cerium oxide (CeO) the basic curve is created (11 hours)
Making a Pitch lap After grinding, a new
tool is made out of pitch. This is used
to polish the mirror smooth.
Polishing After(8 hours minimum)
Testing This done concurrently with polishing and
figuring. (it only takes a few minutes with our
robotic
foucault tester)
Figuring It might only take a couple of minutes
and a few strokes to turn a spherical mirror surface
into a fine parabolic reflector.
Instead of glass we use
ceramic tile glued to a wooden base
as our grinding tool
We have molds for making many
different shaped pitch laps
|
Supplies List
Blanks can be purchased from the following companies:
Willmann-Bell, Inc.
(804)320-7016, about 5 days for delivery.
You can now order mirror blanks direct from their website.
ASM Products Reg"d Canada
BVC Black vitrified ceramic blanks
(514)898-3990, About 6 to 8 weeks for delivery.
Newport Glass Works, Ltd.
(714)642-9980, allow 10 to 14 days.
United Lens Co., Inc.
259 Worcester St.
Southbridge, MA 01550-1325
(508) 765-5421
Grit
Ocean State Abrasives
www.osabrasives.com
Ebony Star Formica
C&R Decorative Surfaces
727 328-8669
ScopeStuff has precut ebony star strips
They also have small precut pieces of teflon too.
Tubes
Tampa Tube went out of business in 2007
CMC Construction Services
AKA Shepler's
1201 North 34th Street
Tampa, FL 33605
(813) 248-5959
Weather Stripping
American Discount Marine
6000 66th Street N
St Petersburg, FL 33709
727 546-8484
($0.85/ per foot)
Plaques
All American Trophy Works
6240 39th Street N Ste B
Pinellas Park, FL 33781
727 525-6880
($20 for a nice plaque to put on your
scope with specs and a nice mirror
lab logo)
Woodcraft
woodcraft.com
18891 US Hwy 19 North
Clearwater, FL 33764
Phone: 727-532-6888
Coating
Club members offer Aluminum only coating at $5/inch.
Bring your mirror by the lab on Saturday and we"ll coat it
and return it to you on a following Saturday.
Spectrum Coatings
spectrum-coatings.com
|
