this Web page last updated Apr 5 2005. Copyright 2005 Herb Johnson
![[8-inch mirror]](mymirror.jpg)
Here's some of the work done on April 18th 2005, at Gordon Waite's ATM session. My work, Gavin's parabolization, Michael's polishing, and Gordon's "hands-on" for my mirror are featured. These images and further description will be moved to my mirror page soon.
On Herb's mirror at 9PM:
facet_apr05.jpg shows the microfaceting, I did it twice this evening.
9pm_ron.jpg is a Ronchi at 9PM after 20 minutes of c-c mirror on top
9pm_fou1.jpg is a Focault at 9PM: see the belly-button in the center? and the shallow zone at 50% diameter?
The numbers for this round: center @ .130, the hilltop is .080, that's a .050 difference. Better than last time's value
of .120, so I'm making progress.
On Herb's mirror at 11PM:
11pm_ron.jpg shows that after another 20 min of c-c polishing, I've DEEPENED the oblate spheroid..huh?
Here's the numbers: 260 for the outermost zone, .330 for the 50% ring, .400 for the ring around the center peak, .470 at the very peak. So
my general difference is now .140, plus a belly button at .070 more. It's gettting worse again, more oblate. This with the mirror on top.
Gordon is perplexed.
Gordon says "you got some time? Let me polish your mirror - just 20 minutes."
I watched, took notes. Gordon cleaned up the lap, microfaceted it, and worked the mirror over it.
gordon_happy.jpg Why is Gordon happy, in this slightly blurry image? Why
is he shouting "King of the World!"? Check the monitor...
mid_ron.jpg The Ronchi tells the story. 18 minutes of Gordon's magic mirror moves..
mid_fou.jpg ..and you can see he achieved a sphere! Numbers say it's 1/11 wave sphere, even 1/2 wave paraboloid!
mid_fou_con.jpg A higher contrast Focaultgram shows a little hollowing at 50%
The numbers are listed below in "zonal measurements" for Apr 18th. My notes on Gordon's work will follow soon.
On Gavin's mirror:
gavin_fou.jpg is Gavin's work to parabolize what was a sphere. Center is a little deep.
gavin_ron.jpg is Gavin's deep hole in a Ronchigram.
The numbers from hell: .450 for the outer sphere, .080 for the bottom of the hole.
..but you should not feel so all alone...EVERYbody must get stoned...
michael_ron.jpg Michael's big mirror is making good progress, in this midnite Ronchigram.
zonal measurements on Herb's mirror:
Jan 17th Jan 31st Mar 7th Apr 18 Gordon deltas for perfect parabola 11:30PM midnite 11:40PM midnite 113-3/16" f.l. 8-inch mirror cntr: .311 .402 n/a .160 .000 zone: .351 .416 n/a .152 .017 zone: .386 .438 n/a .153 .014 zone: .418 .452 n/a .160 .014 outr: .448 .480 n/a .161 .014 ----- ----- ----- ----- ----- diff: .137 .078 .065 small .060
Herb Johnson
Contact information:
Copyright © 2005 Herb Johnson
