Adventures in Eyepiece Cleaning
Submitted: Wednesday, 15th November 2006 by Scott N. Mitchell
The author takes no responsibility for any problems that may occur from cleaning your eyepieces as outlined here. If you are in doubt or have any questions please contact your eyepiece manufacturer or local retail reseller to confirm what will and will not work on your optics. It is not possible for the author to be absolutely sure about what will or will not affect your eyepieces as there are just too many different types of eyepieces and coatings to test them all. So proceed at your own risk and please exercise your own common sense. I am neither an optician nor an eyepiece manufacturer. I am an amateur astronomer with the emphasis on amateur. I will set out to describe what I do and what seems to work for me. I offer no warranty or promise that what I do is right for you and your equipment.
And so it begins
My first eyepiece cleaning journey began when I returned home from one of my first public viewing nights that I attended with a telescope. While I was putting my eyepieces away I made a horrible and shocking discovery…my eyepieces were dirty! I was not sure what to do and unfortunately for me, my eyepieces did not come with a set of cleaning instructions.
I really was at a bit of a loss on how to go about cleaning my precious eyepieces and turned immediately to the internet where I found a whole range of opinions and sometimes conflicting suggestions. I read everything I could find on the topic and after some consideration and soul searching and armed with imperfect knowledge I decided to dive in and clean my gear.
An interesting (or not) aside
At this stage I think that it is helpful to the reader for me to offer my opinion on what some believe is a sensitive subject. Do note that there are two basic types of people when it comes to cleanliness of astronomy gear. For simplicity sake I will refer to these two people types as the “Felix Type” and the “Oscar Type” after two of my favourite TV characters from the classic TV show ‘The Odd Couple’. For those of you not familiar with the show, Felix was a high strung neurotic neat freak and Oscar was a much more relaxed and laid back slob of a fellow. The show in large part revolved around their struggles in living together having been thrown together under an interesting set of circumstances. For the record, I am much more like Oscar than Felix and I tend to adopt a much more relaxed approach to cleanliness of all things (including Astronomy gear).
Even after admitting that I am at least in part a slob, I still do believe that having clean eyepieces gives you the best opportunity to have the best views possible and keeping your eyepieces clean in the long term is probably better for their longevity and the longevity of their coatings than not keeping them clean. So in a nutshell, I try to keep my eyepieces reasonably clean and relatively tidy.
Optical coatings…are they fragile or not?
Your answer to this simple question will clearly influence how you proceed with cleaning. I will not debate this question here but simply state my opinion.
I have stated my experience level with high end optics (more directly my lack of experience) and my tendency toward “Oscar-ness” (some might say slothfulness) so take my opinion with a grain of salt. I do not believe that eyepiece coatings are particularly fragile. Eyepieces are meant to be used and they have been built with the idea that they should be able to stand a little wear and tear. For the record I have even been known to let my sons (age 5 and 9) use my eyepieces and also help in the cleaning process. Eyepieces and the coatings on them were meant to be used by people not put in a museum display case.
Handled with a little common sense and normal care I believe that eyepieces can handle a lifetime worth of viewing and cleaning. If you disagree with my opinion on this point then please read no further…
Okay, so now that we have gotten rid of all of the Felix type people us Oscars can get down to cleaning our eyepieces.
First things first
In my opinion there are too many things that can go wrong by cleaning eyepieces in the field. I believe that eyepieces should only be cleaned in a clean environment that is comfortable and well lit. While I have watched some people try and “clean in the field” and or clean at night (or in the car etc.) it is not something that I feel comfortable doing.
That is why when I am going to clean my eyepieces, I set up in one of my wife’s “clean areas” at home…usually at the dining room table. It is comfortable, well lit and clean and it gives me plenty of room to spread out. I also find the best time to clean my eyepieces is while my wife is out running errands or otherwise busy outside of the house (what she does not know will not hurt her).
The next thing I do before I begin is to gather all of the stuff I feel I need to do the job properly. I will once again remind the reader that this is what I actually do on my own eyepieces…it seems to work for me. Your methods, techniques and equipment choices probably do vary from my own and that is okay with me. Count on and use your own judgement and commonsense in this task and do no feel obligated to follow my way blindly…after all, I am not an expert.
Remember to be careful in the handling of your eyepieces as you clean them. There are few things more irritating to me then to put a fingerprint accidentally on a newly cleaned eyepiece lens. Some people might advocate the use of wearing gloves in the cleaning process but I find that a bit over the top and I think it would introduce more risk of mishandling into the process.
My cleaning gear
I use the following things to clean my eyepieces:
How I clean
In this order here is what I actually do:
Okay so that is how I go about cleaning my eyepieces. I am confident that other more experienced amateur astronomers or pickier (Felix type) people will have different methodologies and quickly point out the error and risks of my ways. They may very well be right and I am open to new ideas and suggestions for improvement. I again urge you to use your own judgment after all, it is your equipment.
I believe that any cleaning regime needs to have a similar pattern and so in summary here is mine: