Mar. 6, 2023: A Big Anniversary!
All text and images copyright Michael E. Lockwood, all rights reserved, unless otherwise noted.
Recently I realized that a major anniversary was coming up. It actually showed up a bit earlier than I thought, so there was not time for anything elaborate in terms of a celebration, but a few friends came over to note the date.
It was the 20th anniversary of the completion of my first mirror, an 8" f/3.9.
I still have the original box that the Willman-Bell kit came in, with the label with our old Michigan address on it. I started out shooting for an f/8 curve, but at some point along the way, I changed my mind and went for f/4-ish.
However, the mirror work started long before it was completed, and is a story in itself.
At approximately 4:10 pm on Dec. 17, 1989, I made my first grinding strokes. You might wonder how I know this exactly, perhaps it was in the grinding log?
No, it's much better than that - it was recorded by my Dad on the family VHS camcorder. He recently transferred the video to DVD and gave it to me along with some others. I had completely forgotten that it existed some 34 years later, and watching it just about stopped me in my tracks while making me smile at the same time. I was nearly in disbelief that it had been recorded so well, and that my Dad took the time to record it.
I should not really be surprised though, the video camera was almost ubiquitous as we grew up, recording many events on tape that I will cringe at and cherish in the future. Also, my Dad loved cameras and took a lot of pictures, so video was a natural medium to add.
A screen shot of the very beginning of the grinding process is below, with the grinding board mounted on top of a very large wooden spool that once held electrical wire. The sound of glass being ground with large carborundum grit is heard clearly and loudly.
It's priceless, really, a recording of the moment of the literal birth of my hobby that would later become a second career.
Watching the video is a trip back in time, with clips of me grinding, washing the mirror, etc, on the 2nd floor of our old house in the woods in Michigan, with the radio playing music of the time, ads, and weather forecasts.
My Dad said he actually remembered my Mom yelled up the stairs asking what the awful noise was!
I see myself holding up the mirror in front of the window to check for larger pits from the previous grade of grit, and I note the snowy scene outside that I have not seen for decades, complete with an A-frame treehouse that we had built with a huge amount of snow on its roof. Of course throughout I'm also talking to my Dad in an annoyed manner as he asks questions about the process, and I answer snarkily as a teenager would.
A later segment of video captures the pouring the first pitch lap with lighter colored burgundy pitch, and then waiting for the pitch to set up so that I can use the mirror to push it into shape while it's still warm. It's all there to see on the kitchen counter, covered in newspapers, with a big can of turpentine, used for tempering the pitch to what I thought was the right hardness, prominently displayed, along with Richard Berry's book about telescope building and mirror making. It also shows the carving of the first pitch lap, and the loud shrieking/squeaking of the glass as I began polishing.
I still remember the smell of that pitch, but it's long gone due to its hardness. I now use Gugolz 55 and 64 instead, which smells much different, but works much better. The video ends abruptly with me polishing the mirror while walking around the stand, and the audio of some long lost game show on the TV in the background.
It's a snapshot in time that I am grateful for, since most of that life is gone. We moved to Cincinnati just over a year later, and I never got to use the mirror under the dark Michigan skies that I was lucky to live under for my first 15 years. (I did, however, take my 10" f/6.8 back up there the last time I visited a couple of years after leaving.)
I haven't pulled out the grinding log for some time, but I remember becoming decent at Foucault testing with my old slit-type tester (later converted to slitless to complete the mirror), and then having massive difficulty controlling the figure of the mirror. I got to a sphere at one point, and I should have quit and built the telescope, but I wanted to parabolize, and that did not go as planned. The hard pitch and likely poor quality cerium oxide no doubt caused the difficulty in controlling the figure and the sleeks that I recall cursing.
High school and my after-school job interfered with finishing the mirror, but I do remember working on it a bit after we moved. I think it was mostly frustration with the pitch and sleeks that kept me away from working on it. I built a 5.25" from a mirror that I was given, but that mirror had been etched by a mouse literally decomposing on its surface, and it did not perform well. Then I built an 8" f/6 with a purchased mirror, and then a 10" f/6.8 with a mirror salvaged from a telescope in the basement of the Cincinnati Astronomical Society, which I was a member of. I watched Shoemaker-Levy hit Jupiter with the 10" f/6.8 in my parents' driveway, while talking on a very novel (for the time) cordless phone to someone, I just can't remember who.
Below is a photo of those three telescopes in my parents' driveway. The 5.25" on the left got rebuilt, the 8" f/6 on the right was sold to a friend at some point. And the mirror kit sat, unfinished.
Getting my undergraduate and graduate degrees kept me far too busy to think about finishing the mirror. I was active in astronomy clubs at both Rose-Hulman and Illinois. I observed comets Hyukatake and Hale-Bopp while at Rose-Hulman with binoculars and telescopes there, and I have a sketch that I need to scan and post somewhere.
Finally, after finishing graduate school at Illinois in 1999, in 2001 I bought a house, and after completing some remodeling, one day I decided that it was time to finish the mirror since I now had space in the kitchen for a grinding stand. I replaced the grinding board with a grinding stand with a more compfortable height, and I still occasionally use it for hand-figuring flats. I went to work on the mirror every evening.
With a bit of advice over the phone from Dick Wessling, to whom I had been introduced by John Pratte, I managed to figure the 8" mirror, which had somehow become an f/3.9. I used a subdiameter lap and slowly approached the proper figure, tested in my dining room in the evening, and took the readings to work in the morning to use a computer analysis program because I didn't have a computer at the time. This would be a routine for much of my early mirror making.
On March 6, 2003, I declared it complete, 14 years and four months after it was started. It went off for coating, and I finished off the telescope and took it out to observe the Mars opposition as well as many other things.
Next I refigured the 5.25" and the 10", and then it was off to the races. My first really big mirror project was Bob Holmes' BVC 32" f/4 in 2006, which has now imaged more asteroids than just about any other amateur telescope in existence.
Now, another 20 years have passed, and I sit here typing this in the optical shop where a 12.5", a 20", and a 28" are being readied for figuring. I can honestly say I never expected to be here, but it's great that I am. (I will have more on that 12.5" in the future, its use will be interesting.)
Does it feel like 20 years? Yes, actually. It's been a lot of hard work and long days, but I have learned a lot, and that seems to be what I enjoy most in life - learning.
On a breezy, but mild, Monday, March 6, 2023, I fired up the grill to make some food for three friends that were free for dinner. I pulled out some old beer that I had aged and saved for many years, some of it appropriately named! The front five were brought out of the beer fridge, but the unlabeled bottle is mead, and we did not open that one. (Coincidentally, that mead was made by a friend that made a small mirror in my basement about 15 years ago, and whom I need to harass to build a telescope for.)
I grilled veggies, brats, and pork tenderloin, and we toasted the anniversary. The Deschutes "Mirror Mirror" barleywine was a hit, followed by the 2014 Old Stock Ale, one of my favorite barleywines, but slightly past its prime. If it had been cold the whole nine years that I had it, it might have been a bit better, but it was in the beer "cellar". The Terrapin reserve was a really nice dessert beer. The HopSlam was opened the night before, and we finished it off, too.
I had already set up the 8" f/3.9 on the tripod that I had built for it just after it was completed. As the sun set, Bob snapped some photos for me to record the event.
The temperature plunged as the sun went down, and the wind picked up and became very gusty, but we all had a nice look at the moon through the telescope before taking everything inside to sip a bit of beer in some warmth and quiet.
Who knows what the next 20 years will bring, but it will be fun to find out.
Thanks to my friends for joining me that night, and to my parents for getting that mirror making kit for me and for making sure that the birth of my second career was so carefully documented.
Thus ends this article, just over 34 years in the making.
Please check back for future installments of "In the Shop".
Mike Lockwood
Lockwood Custom Optics