Cleaning a Takahashi FC100D Objective!

[mikeDnight]

  I've had my FC100DZ for four years now, and I felt it was about time I gave the objective its first clean.

 Many tread cautiously when cleaning such a precious lens, and that's wise, but there's no need to be overly fearful, because the design of the FC100D lends itself to easy cleaning, even if there's dust or condensation marks on the rear element. So because of this I thought I'd include some informative pic's that may help.

It's also good to know that none of what I'm showing here, affects the collimation of the telescope in anyway.

  With the DZ version the first pic's show the removal of the retractable dewshield. But other than that, all the FC100D series are identical in their lens cell construction. So here we go -

Pull dewshield forward and unscrew anticlockwise, holding the silver slider firm at the same time. With other versions just unscrew from the silver back cell.

 

Next, gently unscrew anticlockwise the shiny front section of the lens cell which contains the objective.

At this stage you could check the scope tube for dust and blow it away if there is any.

Placing the cell on a clean surface blow dust off it using a bulb blower. Takahashi warn about using compressed air blowers as they can blast dust scratching the lens coatings, but more importantly can cause thermal shock to the rear fluorite element due to the refrigerants they contain.

  I've misplaced my Caloclean lens spray that would be sprayed onto the lens cloth, so in my case, after I'd blown any free surface dust from the surface of the front lens, I simply used my breath to dampen the lens before gently wiping from centre to edge. 

 Once happy with the lens I turned the lens over and repeated the procedure on the rear element. I did not attempt to dismantle the elements!

It may be necessary to hold the lens cell up so you can check the lens against the light, after which and if you are happy with the clean, gently screw the lens cell back onto the tube cell and replace the dewshield. 

Happy Tak for another few years! 😁

[John]

Nice job Mike 👍

I've done my DL once and it looks just the same under the dew shield.

 

[Space Hopper]

That looks nice and clean.

Not familiar with 'Caloclean lens spray'........can you use Baader Optical Wonder (and Baader lens cloth) for something like this ??

And like you say, i've never felt inclined to clean a refractor optical element (treading cautiously) but i have used it on my Panoptics and also a C8 corrector plate and its worked a treat.

[Mr Spock]

Aren't you supposed to lick it? I'm sure I've read that somewhere...

[Peter Drew]

Post for each side of lens?    🙂

[mikeDnight]

56 minutes ago, Space Hopper said:

That looks nice and clean.

Not familiar with 'Caloclean lens spray'........can you use Baader Optical Wonder (and Baader lens cloth) for something like this ??

And like you say, i've never felt inclined to clean a refractor optical element (treading cautiously) but i have used it on my Panoptics and also a C8 corrector plate and its worked a treat.

Caloclean was suggested to me by Nick Hudson of True Technology Ltd, and who was the former sole importer of Takahashi into the UK. I enquired as the user manual for my FC100DC said not to use solvent lens cleaners. Nick said to go to an optician and ask for a solvent free spectacle cleaner. Very cheap and effective, and easily obtainable. Baader fluid has been used by many on SGL, but I've never used it. Just don't spray directly onto the lens as fluid could easily flow between the elements.

Edited February 25 by mikeDnight

[JeremyS]

I can recommend this outfit for cleaning OGs, @mikeDnight

[mikeDnight]

30 minutes ago, JeremyS said:

I can recommend this outfit for cleaning OGs, @mikeDnight

[Rusted]

Breathing on a lens is likely to deposit fat droplets full of bacteria, viruses and who knows what else. My fuzzy logic suggests that imbibing a spirit alcohol prior to spitting on the lens would be beneficial. The timing of said consumption, prior to the act of deposition, is crucial to the longevity of one's pride and joy. Too soon, and wayward behaviour including false confidence in one's mechanical dexterity are at serious risk. Too late, and the precious fluorite element may simply dissolve before your very eyes.  Or appear to do so.
 

[mikeDnight]

29 minutes ago, Rusted said:

Breathing on a lens is likely to deposit fat droplets full of bacteria, viruses and who knows what else. My fuzzy logic suggests that imbibing a spirit alcohol prior to spitting on the lens would be beneficial. The timing of said consumption, prior to the act of deposition, is crucial to the longevity of one's pride and joy. Too soon, and wayward behaviour including false confidence in one's mechanical dexterity are at serious risk. Too late, and the precious fluorite element may simply dissolve before your very eyes.  Or appear to do so.
 

Bacteria with a hangover. I use Toilet duck for mouthwash, so I think I'll be ok! 😄

Edited February 25 by mikeDnight

[Mumia]

Congratulations on a successful procedure. The patient appears to have survived the surgery. Recently I cleaned the cell in my FS 102, a slightly more complicated procedure because it required re-collimation, but luckily everything worked.

[The60mmKid]

Nice job, Mike. Looking forward to seeing additional festoons in your sketches, now.

[JeremyS]

46 minutes ago, The60mmKid said:

Nice job, Mike. Looking forward to seeing additional festoons in your sketches, now.

I don’t know about festoons, but @mikeDnight will be seeing more barges

[dweller25]

Looking good Mike 👍

Edited February 25 by dweller25

[mikeDnight]

37 minutes ago, dweller25 said:

Looking good Mike 👍

The scope or the similarity between Wallace & family?

[Telescope40]

Steady as she goes there @mikeDnight👍👍

[bosun21]

On 25/02/2024 at 17:32, mikeDnight said:

Caloclean was suggested to me by Nick Hudson of True Technology Ltd, and who was the former sole importer of Takahashi into the UK. I enquired as the user manual for my FC100DC said not to use solvent lens cleaners. Nick said to go to an optician and ask for a solvent free spectacle cleaner. Very cheap and effective, and easily obtainable. Baader fluid has been used by many on SGL, but I've never used it. Just don't spray directly onto the lens as fluid could easily flow between the elements.

I've been using Caloclean for years now as well as their microfibre cleaning cloths. They are excellent and just handling the cloths you can immediately feel the quality of the fibres.

 

 

Edited February 26 by bosun21

[Mr Spock]

Looks like a good product 👍

[Mr Spock]

Just bought both off Amazon - not that expensive! My 120 needs a clean so it's a perfect opportunity.

[HollyHound]

Thanks for taking the time to show this procedure Mike 👍

I have both Caloclean and Baader Wonder products and probably should give my DZ a clean sometime too, but always been very wary of going anywhere near refractor objectives 😬

This gives me some confidence to give it a go... very very carefully 🤞

[Rob]

Nice job indeed. And really useful to share. 

I did the same last weekend with my ED80. I just wanted to share for those that are maybe using Baader Wonder fluid as your point is very valid.

I add one additional step and although my refactors are not Tak's I do use Baader wonder fluid and the Baader microfiber cloth. After cleaning the removed the lens. The only additional step I take before re-screwing the lens back into the tube is that I wrap my dew heater strap around the lens cell and leave powered on medium level (its a usb type) for 15 mins. This should allow you to feel sure all liquid has evaporated even if it had moved between the air spaced lenses. 

Good post mind, Thanks

[johnturley]

12 minutes ago, Rob said:

 

After cleaning the removed the lens. The only additional step I take before re-screwing the lens back into the tube is that I wrap my dew heater strap around the lens cell and leave powered on medium level (its a usb type) for 15 mins. This should allow you to feel sure all liquid has evaporated even if it had moved between the air spaced lenses. 

Good post mind, Thanks

Some Refractor manufacturers, including Explore Scientific specifically state in the manual that the lens should not be removed, saying it is not possible to reinstall it in an accurate position without expert knowledge.

I wouldn't have a clue how to remove the lens from my Esprit 150, and wouldn't attempt it anyway. I know that deposits can build up on the inside element of a lens, and I used to remove and clean the lenses in both the Vixen 102mm Achromat, and Astro Physics 6in f8 Refractors that I used to own, but the lenses in both those telescopes were easy to remove and replace.

In order to reduce the possible build up of deposits on the inner lens elements of my Esprit 150, and Tak 100DZ, I keep one of these desiccant caps in place as the end of the focusing mount when the telecope is not in use.

John 

Astro Essentials Dual-Fit Desiccant Cap Red | First Light Optics

 

[Paz]

I read the astro physics guide to cleaning in my formative years and they advocate the following...

1. Blowing with air to get rid of anything not stuck to the lense.

2. Brushing lightly  to get rid of anything lightly stuck.

3. Baader Optical Wonder Fluid to get most things off.

4. Acetone or your breath to clean off baader fluid streaks.

5. Saliva to get rid of super tough atmospheric contaminants... but the saliva then needs to be cleaned off fairly quickly.

However, lense licking fetishists will be disappointed to hear that the recommended method is saliva on a fingertip, not licking lenses directly.

https://astro-physics.info/tech_support/accessories/cleaningproducts/optcs-instructions.pdf

Could this where the lense-licking folk lore originates from?

I think cleaning is a very personal thing, my take on the above options is...

Blowing 😇

Brushing 😬

Baader Fluid 😇

Breathing 🤔 yes but very lightly to avoid giblets on my surfaces

Acetone 😬

Saliva 🫣

Edited February 27 by Paz

[Moonlit Night]

I cleaned my scope recently, first time in several years. It’s not a big deal really as long as you’re careful. I stop at Baader wonder fluid and a micropore cloth…

[Moonlit Night]

Incidentally, I thought fluorite was water soluble?