How to Clean a Telescope Mirror

How the clean a telescope mirror. - YouTube

I recently took the plunge and bought a big Dob. I got it somewhat cheap because the person selling it (favor ‘im) clearly thought the aluminizing was shot. It wasn’t: he’d kept it in the kitchen and the mirror had a flimsy film of cooking grease that made it look dull. Presently a touch of residue and dew-spotting on a mirror is best taken off alone, yet this worked out in a good way past that and it required a clean. However, how?

So I did some research, at that point took a full breath, and poured a gallon of water in the business end of my new Dob. Before the finish of the cycle, my Dob mirror looked like new, so I’ll share it with you utilizing a lot smaller mirror so it’s easier to perceive how it’s finished.

The entire cycle takes about 40 minutes. You can eliminate the mirror (as in the photos beneath) if it’s a small one, however, I did my dob’s 16″ mirror in situ, as I figured that the dangers of eliminating it were greater (incidentally, Starmaster telescopes agree).

Usual disclaimer that I take no duty if this turns out badly (however on the off chance that you adhere to these directions no reason why it should).

Stage 1 – Clear your workspace

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First things first. On the off chance that you do the washing up (and you do, don’t you?) fine – you’re in charge. In the event that not, at that point lock your significant other out of the kitchen for the duration.

Stage 2 – Feel the fear and pour anyway

How dirty is my Mirror? - Reflectors - Cloudy Nights

You can’t wash a goal focal point. In the event that you attempt you’ll probably get water between the components. However, mirrors are a single component and generally sit in open cells. So however it feels bizarre (really off-base, actually), you can for sure wash them, and doing so arguably opens them to substantially less scratching than utilizing wipes and cleaning liquids.

  • Unless your water is hard you can utilize clean tap water for this (a valid justification to utilize a container is that you can spot floaters from the tank before you pour!)
  • So you start by pouring on enough water to fill the mirror and then a few. I’ve seen shower heads utilized, however, I just poured delicately from a carefully-washed container. This will wash off loose residue and muck.
  • I don’t have to warn you about the dangers of dropping a container (or showerhead), so hold tight while you’re doing it!
  • Now let it soak for a moment or two.

Stage 3 – Add cleanser

Telescope Mirror cleaning - YouTube

A few people have utilized washing up fluid. However, there is a potential issue. Washing up fluid frequently contains salt to diminish smearing and this <might> affect the coating. So to err on the side of caution I utilized a special cleanser that came with a unit for washing spectacles utilizing a special bath. The unit (by ‘Freiblick’) came from Germany, where they are apparently normal, yet I found a similar thing here in the UK advertised as a ‘focal point bath’.

  • Squeeze on somewhat cleanser – perhaps 20 drops on a major mirror, yet the small one shown required only a couple.

Stage 4 – Wash your hands

How to Clean a Telescope Mirror

How about we move the complaints. Many feel appalled at touching a mirror, however, several leading specialists suggest it, with careful control and understanding.

In any case, first, wash your hands completely (multiple times in my case), utilize a scouring brush if necessary, and don’t touch anything else before the mirror!

  • Obviously, in the event that you fill in as a manufacturer, or garden a great deal, you would need to take special care to eliminate any trace of coarseness (or better get another person to do it, as I accomplished for the photos).

Stage 5 – Swirl

Telescope Mirror cleaning - YouTube

  • Swirl the soapy water about on the mirror delicately with your fingers (you don’t have to touch it yet).
  • Leave it to soak again for a moment or two.

Stage 6 – Clean the mirror surface

Uncle Rod's Astro Blog: Mirror Cleaning Madness

  • Using exceptionally lightweight and the pads of your fingers, work over the entire area of the mirror to clean it. Try not to rub! A delicate, floating movement is all that’s required.

Stage 7 – Rinse


  • Unless your water is delicate or you’re not fretted over a couple of watermarks, you’ll need de-ionized water for this stage. I purchased a liter from a hardware store for a couple of pounds.
  • Pour the water onto the mirror until all the bubbles have gone.

Stage 8 – Dry

Difference: Dirty MIrror/Cleaned Mirror - Deep Sky Observing - Cloudy Nights

Stand the mirror (or mirror box or OTA) on its side and let the water drain for fifteen minutes or something like that.

  • Let the mirror air-dry, yet use a kitchen towel to dry the cell and OTA (if the mirror is in situ).
  • You can tenderly, in a good way, blow warm (NOT HOT!) air from a hair drier to enable the drying to measure.
  • You should now have a completely clean, as a new mirror. No marks, no scratches, no greasy haze.
  • Clean mirror (apart from two or three dusty filaments got while drying).


Seeing buildup on your telescope focal point or mirror is adequate to make you stress that its quality is diminishing.

However, as we’ve found in this article, you shouldn’t pressure too significantly over a dab of buildup. If you have more than a touch of buildup, or various imprints on your focal point/reflect, by then you should clean it by following the methods we represented in this article.

The principle action is to take as much time as is needed and work progressively. Concerning how to clean telescope lenses and mirrors, it’s imperative to treat them with the most outrageous consideration!

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