Are Alignment Telescopes and Autocollimators hard or easy to use?

Are alignment telescopes and autocollimators hard or easy to use?

Good question! The answer is not simple and it is non-trivial. Before getting to the answers I propose to give, I’ll say this about those instruments: They are (both of them) good, useful, adaptable, and in some applications also indispensable measuring instruments. My own work experience with autocollimators and alignment telescopes has spanned over 40 years, and I guess that comment gives away some fact about my age! I have used various types of both instruments made by different manufacturers. All my experiences with them were pretty good.

When I got the fortunate opportunity to work hands-on with developmental optical equipment, I sort of accidently “fell into” the application of both types of instruments while doing accurate optical alignment. I discovered in less than the first week that I loved doing that stuff, and worked to learn about alignment, practice it, use it, and continue to the present day. Thus, my own personal story with alignment telescopes and autocollimators is one which includes a lot of hands-on experience, exploring different equipment, and learning some lessons the hard way.

Back to the question, with a quick answer first. Using these instruments can be easy or hard; it depends upon your experience, the tasks required by your application, but mostly it depends upon your attitude towards this work. Yeah, really, your attitude. That’s because some people find this kind of work a crushing bore and a pain, while other persons find it a joy to do and an inspiration. Evidently, I fell into that latter group. If the reader has worked in optical engineering for at least a little while, you probably have recognized that some optical engineers never pick up a wrench or a screw driver in their line of work, and do not care to. Others use all the tools they can get their hands on, and get their hands dirty and may occasionally drop a lens on the floor. That is “life” in this particular vocation. I was the kind of engineer guy who liked the tools, the grease or chemicals on my hands, and who spent many hours or days adjusting mirrors and lenses in equipment I also designed. (Fortunately I did not drop many lenses on the floor.)

If you are about to use an alignment telescope and/or an autocollimator for the first time but have zero prior hands-on experience, here are a few suggestions. If it is possible, talk with some person who has been doing optical tooling with these instruments. A few discussions like this can save you a lot of time and wasted effort by putting you on the right track. My own experience went like that. When I embarked on my first job at a large observatory, my experience with optical tooling techniques was close to nil. There I met a much older gentleman who was also an engineer at this site and had worked for the Argus Camera Company (the original one) in Ann Arbor, Michigan. He had a long history of optical tooling and alignment with Argus and was putting his background to good use at this observatory. I offered to become his assistant with what was then his current project. Once he observed that I was a quick learner and that I respected optics, we became good technical associates and he taught me how to use alignment telescopes and autocollimators. This saved me from learning by mistakes and put me on the right track.

In the event you do not have this option, be sure to read the equipment user manuals which you have and any other information you can find on the world wide web. The main point here is: be sure you understand exactly how the instrument works and what you can expect from it in terms of its accuracy and its intended use in tooling applications. These instruments are often quite different from one model to another, and their actual performance specifications are genuinely important, so you ought to be familiar with what they say.

The next step for a novice would be, play with the instrument on the optical bench or even on your desk if you have to. Get used to operating its controls and learn how to interpret what you see in the images. (Of course, for a person who is not a novice and has lots of experience with these, you probably will not need to read this article at all.)

After a few experiments you will surely notice that both alignment telescopes and autocollimators are extremely sensitive to movements and therefore to any potential instabilities in their support and retention mechanisms. They simply cannot be subject to bumps or vibrations or any retention method which is not secure or not repeatable, in the event you will need to remove and replace the instrument in your application. It is always best if the alignment telescope and/or autocollimator is not removed from the setup at all, but some applications might require this to happen! In any event, pay attention to repeatability.

When you are in the midst of your measurement procedure, if anything unexpected or strange turns up in your data, don’t hesitate to call the manufacturer of the instrument you are using at that time and ask them questions. One good 15 minute discussion with a knowledgeable tech support engineer or technician at the manufacturer’s level can save you days of frustration and save the project some money.

Back to the original question: “Are alignment telescopes and autocollimators hard or easy to use?” The simple answer: They are not hard to use. They are made to be somewhat easy to use. The longer answer is this: The more experience you have using them, the better will be your own personal answer to that question. In terms of practical results of measurements or alignment tasks, experienced users tend to get better results more quickly than a novice might. That is the same idea for almost everything in hands-on engineering; this is nothing new.

A final few words on the subject of task assignments from management to engineers. (This can be considered slightly divergent from the topic.)

Often, engineers will find that they have been given a task by management which is beyond their personal experience level or even beyond the realm of possibility! When that happens, it is not necessarily a sign of malevolent intentions by the management. It could be. More likely, this happens because managers are adept at managing things, but may not be aware of the real “nuts and bolts” of engineering processes. If it seems that your task cannot be accomplished with commonly available optical tooling equipment, talk it over with other engineers. Then, talk it over with your management as well, when you have a clear idea of the problems inherent in the task you have been given. Avoid diving into a project which demands high levels of skill and instrumentation, but which has a budget restriction that severely limits your acquisition of that instrumentation or anticipates skill levels which exceed yours. Of course it’s true that adding new skills to your skill set often is nearly free of charge, and is usually good to pursue.

Procuring brand new alignment telescopes or autocollimators can be expensive. Be careful using old instruments which were purchased used from an unknown source by means of internet sales. If you are about to use one of these, be sure to confirm that it works and that it is calibrated. On one occasion in my past, it was suggested to me that I use an “older” auto-collimating telescope which had been obtained using the method I just mentioned above. I checked it on the bench and discovered that it did not work at all! It’s always best to be sure you have a viable instrument.

You have all my best wishes for success.