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Cleaning my Tak FC-100D objective - SCARY!!


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This was a job I really did not want to do, quite frankly I was terrified of getting it wrong and scratching the objective. My scope has been used very frequently in a variety of conditions, often quite dewy but also for solar so any dew marks have been well dried on! It was definitely due a clean, as you can see in the first picture; frankly I'm a bit embarrassed at how dirty it was!

I sought advice from MikeDnight who pointed me in the right direction (cheers Mike!) so here's what I did...

In preparation I had ordered a couple of brand new Microfibre cloths from FLO and purchased some solvent and alcohol free lens cleaner from SpecSavers. I also timed this just as I had bought a new brush for the hose attachment on the Dyson.

So, holding the OTA upside down, first off I used the brush attachment with the Dyson to very carefully suck any grit away from around the edges of the objective. I got the brush close to, but not touching the glass, concentrating on the angle between glass and cell.

I then used a jet blower to blow any loose grit from the surface, followed by a very soft brush to gently ease off a few hairs which were stuck to the surface (EDIT probably from our rabbits now I think about it!!) . A final suck round with the Dyson and a blow with the jet blower and I was satisfied that I had everything off that was coming off.

Next up was the scary bit. I sprayed a generous amount of the lens cleaner onto the Microfibre cloth, and used a very gentle dabbing motion to apply it to the objective. I let it stand for a little bit to soften any hardened-on dirt or sap, before drying with a new cloth, again with very little sideways motion to avoid dragging any grit across the surface.

Repeating this process, gave me a result that I was happy with. I will confess to a slight breath on the lens and gentle wipe just to clean a remaining smear off, but otherwise that was that.

I still have some specs of dirt and potentially paint flecks on the inside of the objective to deal with, but I will leave those for the moment as the objective cell does not easily unscrew. The scope's collimation is perfect presently so I would rather leave the specs than knock it out in some way.

I'm sure there are many ways to skin this particular cat, but hopefully some of that is useful to others.

Stu

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Hello and well done. There does seem a lot of debate to clean or not to clean.

I think there comes a point that you have to clean to stop long term damage to your lens. As a combination of dust , grime, dirt, pollens must start either attacking the coatings to the lens or if they are left on to long just make getting them off even more difficult in the long term. I use baader wonder fluid and a nice clean cloth 

I also think a massive build up like shown in your first photo of the lens must effect the quality of image that you see through the eyepieces. To me it's like cleaning the windows in your house. You can see a lot more with better image with clean windows than you can dirty windows 

It would be interesting to see if members agree with this or not

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16 minutes ago, Timebandit said:

Hello and well done. There does seem a lot of debate to clean or not to clean.

I think there comes a point that you have to clean to stop long term damage to your lens. As a combination of dust , grime, dirt, pollens must start either attacking the coatings to the lens or if they are left on to long just make getting them off even more difficult in the long term. I use baader wonder fluid and a nice clean cloth 

I also think a massive build up like shown in your first photo of the lens must effect the quality of image that you see through the eyepieces. To me it's like cleaning the windows in your house. You can see a lot more with better image with clean windows than you can dirty windows 

It would be interesting to see if members agree with this or not

Yes, I think when it gets to the level that mine had it is definitely worth doing. I won't let it get that bad again now I'm confident I have a method that works.

It will be interesting to see if there is any noticeable impact on the views, although I mainly did it out of concern for the coatings, which appear to be totally unaffected which is a relief!

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21 minutes ago, John said:

Good job Stu :icon_salut:

I've done my Vixen and ED120 (both sometime back) but I'd be taking a deep breath before having a go at my Tak or my LZOS :shocked:

 

Yes, I certainly felt there was a lot at stake doing this compared with other scopes I've had. I bought this one new so somehow i feel more protective over it than others

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One wants to emulate Howard Carter when approaching items of that sort.

One night, I aimed my FS-102 at the Moon, and there it was: a bright yellow arc, right there on the limb; shattering.  I put the telescope up and did not use it for a very long time; at least for a year if not two.  Then, one day, I decided to give it a look over, and found that the objective was coated with dried dew and debris; a considerable amount, and for all that time.  Odd, in that it had not been used much beforehand.  After cleaning, and most happily, the false colour was no longer apparent.  Last August was the last time I had it out, and during a drought, but I'm now wanting to use it more often, so I think slipping a flexible felt-coated liner into the lens-shield and adding a lined extension should help to keep the dew at bay.

I made a dew-shield for a C90, using aluminised bubble-wrap, craft-foam, velcro and black felt, and plan to do the same for the refractor.  As to its effectiveness, it hasn't rained much since I made it.  Time will tell.

It's not very elegant, I'm afraid...

C90 dew shield9.jpg

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Stu, the first pic (before cleaning ) looks like you have caught M13 with it :grin:

I have cleaned my TAL objective a few times TBH i believe i have scratched the coating by doing so but it still performs very well, at one point due to storing it in what i thought to be a safe place but turns out it was rather damp it started on with fungal growth on the lens so i had no choice but to open up and deep clean all surfaces, very scary

but you have done a stirling job, looks brand new

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11 hours ago, John said:

Good job Stu :icon_salut:

I've done my Vixen and ED120 (both sometime back) but I'd be taking a deep breath before having a go at my Tak or my LZOS :shocked:

 

 

I think now Stu has raised this cleaning post subject that John might have had bad thoughts put in his head and might be having bad dreams  ,especially  as John has a Tak and the nice new LZOS.  Obviously I think we all do not like to think about cleaning our lenses especially when we are talking about high quality refractors . We are talking about quality instruments and they are not cheap.

The trouble is with cleaning your lens you get a one shot approach at it. It either all goes well and you give yourself a pat on the back and wonder what all the fuss was about, and why you worried so much about doing the cleaning process. Or you see scratch or mark after cleaning and curse yourself for being so stupid to attempt to clean your lens and you should of left it well alone. So it is a difficult decision to make as you seem damed if you do or damed if you don't. 

And during even a few observation sessions it surprising just how much dust, foreign materials etc are floating around in the air and seem to get attracted to all of places your telescope lens. I try to get the Hoover  hose to within a inch of the lens to get the worse off every time there seems to be getting a bit of a build up on the lens. And then only actually physically touch the lens with a cloth when the dust, pollen ect is sticking and IMO you have really got to remove them as I suspect the coatings could be damaged by leaving them ,as I said your damed if you do and your damed if you don't ?  

 

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I dont think photographers worry like this even though some lenses might cost many times that of a premium scope not sure if its down to harder coatings or that the thought of any stuck dirt becoming the nucleus of a fungus attack being a far greater threat.

For me its a quick blast with a dust blower and then a lens pen.

Alan

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I think the really important point here, that Stu pointed out in his OP, is that the FC has to be cleaned using Alcohol Free lens cleaner and he used Solvent Free lens cleaner from SpecSavers. The FC manual indicates a warning that Alcohol cleaners Will Damage the coatings. Other Tak scopes such as the FS series carry no such warning.

There is some debate on CN that seems to indicate the alcohol free warning may be a mistranslation from Japanese to English, and the warning should really read 'Do Not Use Ammonia', which would destroy any lens coatings.

FC owners are wise to err on the side of caution here, at least until the issue has been officially resolved. (Resolved! That's funny!) :icon_biggrin:

Mike

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Great result Stu. I admit to not being a bit fan of touching refractor glass as unlike newtonians they are not as easy to recoat / fix.

It is worth noting though that I recently did some research on a paracorr and read that they recommend optics being cleaned every year to remove spring time grime that can if go unchecked lead to bacteria feeding on said grime leading to damaged coatings. I do like giving all my refractors a gentle wipe over when new to me (not knowing their history) with baader wonder fluid which is said to leave a protective film on the lens. 

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11 minutes ago, mikeDnight said:

I think the really important point here, that Stu pointed out in his OP, is that the FC has to be cleaned using Alcohol Free lens cleaner and he used Solvent Free lens cleaner from SpecSavers. The FC manual indicates a warning that Alcohol cleaners Will Damage the coatings. Other Tak scopes such as the FS series carry no such warning.

There is some debate on CN that seems to indicate the alcohol free warning may be a mistranslation from Japanese to English, and the warning should really read 'Do Not Use Ammonia', which would destroy any lens coatings.

FC owners are wise to err on the side of caution here, at least until the issue has been officially resolved. (Resolved! That's funny!) :icon_biggrin:

Mike

Thanks for your help on this Mike.

The bottle said it contained no solvents or alcohol. It seemed to work very well, creating a tiny bit of soap ones which disappeared quickly and left no smears on the surface at all.

I clean eyepieces regularly as they have an impact on the view being near the focal plane. I avoid cleaning scope objectives until absolutely necessary but I think from my first picture you would agree this was necessary!

image.jpeg

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1 hour ago, Alien 13 said:

I dont think photographers worry like this even though some lenses might cost many times that of a premium scope not sure if its down to harder coatings or that the thought of any stuck dirt becoming the nucleus of a fungus attack being a far greater threat.

For me its a quick blast with a dust blower and then a lens pen.

Alan

I have used lens pens occasionally to clean around the edges of eyepieces, but would never use one one an objective. You may be fine, but the risk of creating scratches is much higher I would think. I prefer for the contact to be wet with a cleaning solution rather than dry.

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1 hour ago, mikeDnight said:

Wire wool and dettol must be safe to use John, as there's no warning in the Tak manual that states otherwise. Let me know how you get on!:icon_jokercolor:

:tongue2:

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