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My Other Telescope is an 8.4 Meter

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My Other Telescope is an 8.4 Meter


By Patrick Stevenson

Former Assistant Supervisor of Large Optics Fabrication

Steward Observatory Mirror Laboratory


I have been interested in astronomy virtually my whole life, starting with grinding and polishing a six inch Edmund mirror back in the early '60's.  Given the times, and my family traditions, I opted for a military career that lasted a total of thirty years.  During those years my association with the hobby was limited to reading and looking at pictures.

Upon my retirement from the Army I did the typical Law Enforcement track.  It only took a year with the Sheriff's Department to realize that I just didn't want to carry a gun anymore.  While looking around for a challenging alternative I ran across an ad for a “Mechanition” (Read Gofor) at the Steward Observatory Mirror Lab.  I was intrigued and applied for the position.  I was promptly told that I was over-qualified.  They felt that with my intensive experience as a retired Army Green Beret, with a Law Enforcement stint, and a BS from Northern Arizona University, that I would become quickly bored and move on.

Since I had virtually no experience in optics of ANY size, I argued that I could not possibly be over-qualified.  My love for the science and desire to work in such a prestigious institution in ANY capacity would more than make up for what I lacked in direct experience.  Still, I was told that I was over-qualified.  I was finally ready to give up but asked one thing before I went away.  I would stop bugging, but I wanted the answer in person.  In what was, I am sure, an act of desperation, I was given an interview.

I met with the Mirror Lab Manager on a typical summer morning and began my tour and interview.  It was clear that the answer was not going to change, but decorum dictated that I be treated as a serious candidate.  I learned that the position was generally filled by an Op/Sci undergrad; far from my age of fifty five, and worldly experiences.  In any case, the Manager lead me through the lab where I encountered the second 8.4 meter mirror destined for the LBT in Arizona.  As we passed the mirror located on the giant test tower, I touched the edge of the monster mirror and smiled.  This apparently piqued the Manager's curiosity and he asked what I was thinking.  I responded that this was not a telescope, it was a time machine.  One that would reach billions of years into our past, perhaps to the origin of the universe.  That comment got me the job!

I was so excited to be a part of something so immense in physical size, but also in technological advancement beyond imagination.  My spare moments between sweeping floors and getting tools for the “real” workers were spent in reading science papers on the projects, quizzing Phd's with stupid questions, and filling notebooks with critical information.  I was, literally, in “Hog” heaven.

By the end of the first year I had become the goto guy to assist the project scientists and engineers.  On one particular occasion I was way up in the test tower along with the Chief Scientist of the Lab conducting tests on the mirror some ninety feet below.  As we had nothing in common, the conversation was limited to “Hand me that”, or “Step back out of the way”.  Desiring to elevate my “serf to master” relationship I mused that it was interesting that this mirror would become significant by utilizing Heisenberg's Uncertainty principle.  I received a tolerating stare and a question from the scientist, “What do you mean by that?”.  I said that since we were using laser interferometry to test the mirror; the wave theory of light, and imaging would be done using CCD cameras detecting photons of light;  the particle theory of light, I found it interesting.  He looked at me for a moment and then said, “Who are you?”.  I replied that I was a gofor in the lab.  Nothing more was said that day.

I continued asking questions and being somewhat underfoot, but harmless.  The scientists and engineers began to notice me and actually engaged in multi-word sentences.  To make a long story short, I was promoted to Senior Staff Technician with an attendant 500% raise and became the Assistant Supervisor of the Large Optics Fabrication Lab.  Why?  Because I showed an insatiable thirst for knowledge and became an asset to the program.  This all happened in my fifty fifth and sixth years.  I had actually become one of the team, frequently invited to meetings chaired and attended by Scientists and Engineers!

The cycle time required to produce a finished 8.4 meter mirror was about two years, if nothing went wrong, which of course, it always did.  The entire process starting with casting, progressing through grinding and polishing, and terminating with integrating the mirror to the steel structure known as the “Cell” which would ultimately become the optical assembly ready to be shipped to some far off mountaintop.  Because of my lack of experience and my age, I searched for documents that would spell out each of the steps in the process.  There were none!  As a career military man, I was stunned!  The whole process was so new that the developers of each major stage; Casting, Polishing, and Integration were still in charge of their respective steps and simply directed work crews based on their memory.  While the system worked well, without proper instructional documentation, the very future of the process was entrusted to the mental and physical health of essentially three men!

I began a two year project of writing and documenting the entire process utilizing a Mil-Spec format that incorporated exact details including digital pictures of each step in the process.  I thought my efforts would be appreciated and accepted without reservation.  I was wrong.  I was presented with the, “If you write it all down ANYBODY could do it!” dismissal.  Job security was suddenly threatened!  I was viewed as a pariah and had to take my efforts underground.  Two years after I started, I completed a nearly two hundred page Mirror Fabrication Specification.  It was instantly rejected and relegated to an obscure file on the main server not to be seen again for almost ten years!

I retired from the Mirror Lab in 2009 and moved to a three acre plot forty miles east of Tucson in the Sonora Desert where I built my own 10x12 foot roll-off-roof observatory where I began astrophotography.  Years passed before I came in contact with my old boss at a Star Party.  Our friendship picked up as though no years had passed.  Although formally retired, he had returned to work part-time at the Lab.  He told me that my Mil-Spec procedure had been resurrected and was required to be used for each process.  My other suggestion that all new Technician hires be required to construct a ten inch Dobsonian telescope following the entire process from casting their own mirror, generating, grinding, polishing, testing, and completing the assembly of their telescope before they could work on large optics had been adopted.  I actually made a difference!   


Patrick Stevenson

Orion EON 130mm Triplet

Celestron CGX mount

ASI120MM Guide camera

Canon T3i modified imaging camera

Orion 60mm guide scope



Five years imaging


Past Scopes:



130mm Parallax APO

Orion 10” f/3.9 astrograph

Past mounts:

Losmandy G11 Gemini 2

Atlas EQ-G

Celestron AVX           


  • Dave Mitsky, Patrik Iver, Joe Bergeron and 63 others like this


Try working there every day!   What a blast!!

Thank you for writing this very stimulating article!

Apparently you took a great rollercoaster ride in the timemachine!

What a lifechanging experience...

It was, and I thought I was too old to see anything new or stimulating.  Goes to show, "It's never too late".

Outstanding article; very interesting story!

Nice inspirational story . I enjoyed reading it . 

Thanks for writing that. Especially including the background. Enjoy your retirement and I sincerely wish you clear skies!

Thank you all for the positive feedback.  This was fun to do.  I'm writing three follow up articles on the entire fabrication process that may be posted.  We'll see.

Clear Skies,


    • b.bill.p likes this
Apr 12 2019 11:13 PM

As an "in the works" tech/scientist myself. This was a truly inspiring read. Thanks so much for not only sharing but also your service! 

Loved the story...thanks for sharing.  Keep looking up! :-)

Patrik Iver
Apr 14 2019 05:41 AM

What an enjoyable and also inspiring read!

Thank you for telling your story.


Opteon (www.opteon.fi) is just down the road from where I live - maybe I should apply for a job there... :-)



Patrik Iver

Thank you for your service*   Got any more wonderful stories for us, please?




* you Groundpounder  wink.gif

Yep, they just posted my second article on fabricating an 8.4 meter mirror.  I have two more articles in the works on the same subject.  After that I may do an article on how I transformed a Big Max garden shed into an observatory.





Apr 15 2019 09:54 AM

This is one of the best reads I have ever seen here in CN.

Thanks Gustavo.  I've seen your website and getting a compliment from you means a lot.


    • gustavo_sanchez likes this

As an Old man often relegated to the "over qualified bin" I loved and smiled while reading this, Thank You!!

Fantastic story of perseverance and dedication!

Thank you for sharing such a great story. It's good to show others how having a passion can turn into something wonderful and fullfilling.

My wife and I visited Tucson this past November and one stop was the mirror lab. It's very interesting. We got to see 3 of the 8.3 mirrors that are destined for the Chili telescope (I think one was just shipped) all in different states of completion. That lab also created 2 mirrors for telescopes on Kitt Peak.

This is really great to read !  I have been underneath the Subaru mirror and it's pretty awesome to know how it was cast.  Thanks so much!!

In regards to the negative response concerning your documenting the procedures at the Lab, wasn't it the only place in the world at that time where such large mirrors were cast? Keeping a lid on trade secrets would have made sense at the time. 

I hope to get down there some day.

There are now two other places where large mirrors are spin-cast.  One in the US and the other in Japan.  Trust me, it wasn't trade secrets, they were all over the internet.  It was pretty much lack of knowledge of how to write procedures, and maybe some laziness.

Great story!  Here is what I think happened.  After you left there was an incident.  Something very expensive that got the attention of the higher ups or investors.  It was big enough to cause a review of the procedures.  Oh! What procedures?  You mean to tell me you have no procedures!?  Well you better get some and get them now!  Side meeting of the scientist and engineers takes place and someone remembers you and your paper, your instructions, your procedures and  wala! They are resurrected.  I worked in the Oil and Gas industry and in the last 10-12 years we had to develop written procedures for every task no matter how small.  Good Job!

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