2008-2009 Stellafane Mirror Class
Session 5 held on 2009-Feb-28

Finished Mirrors

We had two mirrors finish up this session, and as you can see from the photos,
their makers are justifiably happy and proud.

2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Finished Mirrors Fran: 10" f/2 Spherical Dave & Phil flank Fran with his 10" f/2 spherical mirror for a Cassegrain.

2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Finished Mirrors Jeff: 10" f/5 Parabola Jeff shows off his 10" f/5 Parabolic mirror.

2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Finished Mirrors Dave & Jeff Dave helped Jeff with testing & figuring, and poses with the finished mirror.

At the Fletcher House

With Stellafane still snowed in, we met again at the Fletcher House in Chester.

2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 At the Fletcher House Setting Up The brown paper is down to protect the carpet, and students are getting set up to work on their mirrors in the main room at the Fletcher House.

2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 At the Fletcher House Working Along In early afternoon, a row of grinders and polishers work while Phil gets ready to talk in the background.

2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 At the Fletcher House Class Stalwarts Jay & Tom, who a key to making Mirror Class a success, share a light moment in the hall.

Lectures

We had a lecture on Foucault testing for the mirror class,
while the refractor group had a lecture on fabrication procedures and issues.

2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Lectures Ken Talks Testing Ken gives a talk to explain how the Foucault Test works, and how to read Shadowgrams.

2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Lectures Phil Talks Lenses Phil talks to the Refractor Group about fabricating refractor lenses.

2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Lectures Fringes Phil explains how fringes on test plates are read.

Grinding

It's late in course, so most students that are still grinding
are using the finer grits to finish up this stage and then move on to polishing.

2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Grinding AlOx Ready to Go 25 micron Aluminum Oxide grit sits ready for us on a tile tool. Add a little water and start grinding!	2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Grinding Kayla & Rick Rick applies a bevel to Kayla's mirror as she watches.	2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Grinding David David fines grinds and 8" mirror.
2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Grinding Claudio Grinds Claudio concentrates on his grinding.	2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Grinding Gary Chats Gary chats with Phil and Randy as he grinds.	2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Grinding Gary & Tom Instructor Tom checks in with Gary as he grinds.

Laps

With many students moving on to polishing and figuring,
lap making is increasing to support this activity.

2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Laps Banished for Channeling Channeling a lap is a messy job, so Dave & Randy work on the deck to keep the mess outside.	2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Laps Ray & Dave Ray and Dave chat while the lap warms under the heat lamp.	2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Laps Two Nice Laps An 8" lap with mirror on top, and a very pretty 6" lap.
2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Laps Rick & Ray Waiting for the heat lamp to warm up their laps.	2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Laps Randy Presses Randy is about to put his mirror on his warmed lap to warm press it.	2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Laps A Nice 10" Lap Samantha's 10-inch lap, freshly coated with Cerium Oxide, ready for pressing.

Polishing & Figuring

Plenty of work in this area this session.
With Fran & Jeff finishing up, a lot of careful final figuring was done.

2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Polishing & Figuring Take Heed! This sign was attached to the deck door - cold blasts of winter air do make the polishers or the laps happy.	2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Polishing & Figuring Fran Figures Fran figures his 10" f/2 Cassegrain primary. He completed it later this day.	2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Polishing & Figuring Carl & Dave Dave makes a point while Carl listens while polishing.
2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Polishing & Figuring Alex & Samantha They are waiting patiently while they press their laps.	2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Polishing & Figuring Exhausted from Pressing Alex & Samantha just couldn't make it while pressing their laps, after all 20 minutes is an eternity when you are waiting. So the used their heads and applied more weight to the press, while refreshing themselves with a nap.	2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Polishing & Figuring Dave checks up Dave checks Samantha's lap after an initial press. A white 'onion bag' mesh is being used to micro-facet it. He checked Alex's lap right after this.

Testing

Testing is done in the lower game room at Fletcher House.
We had several testers in use, two on 'rails' to help keep things lined up,
and Dave's beautiful machined aluminum double-pass tester.

2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Testing Two Railed Testers Rails help keep alignment when you need to adjust the mirror to tester distance. In the foreground, Jay's tester use a ladder for this, in the background Ken's tester uses two 10-foot electrical conduits.	2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Testing Ken's Tester The test head on this, before the rails where added, was the prototype for the popular 'Stellafane Tester'.	2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Testing Jeff's Mirror Jeff's mirror sits on the test stand. He built the nice box to carry it around in at lower left.
2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Testing Jeff's Ross Null Tester This is Jeff's Ross Null tester. This test uses a lens to null a parabola in a knife-edge test.	2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Testing Ray & Claudio Ray & Claudio are new to testing. They practice aligning the tester on Ray's mirror.	2008-2009 Stellafane Mirror Class Session 5 held on 2009-Feb-28 Testing Testing at Radius Ray & Claudio watch Dave (hidden behind the tester). Although the big flat mirror on the tester tells us this can be used as a double-pass tester to test at focal length, here it is being used in single-pass mode testing at Radius of Curvature.