17 replies to this topic

[Cielo_nocturno]

On my Televue Delos 6mm has appeared fungus on the top of the eyelens.

Researching online I've found someone who disassembled it before but he didn't take away the top lens where is the fungus, to be able to clean it, it seems like the lenses are grouped in three parts but I don't know if each part can be removed to be able to clean the affected top lens.

Has someone did it before so I know it's possible to clean it before try to disassemble?

Before you tell me to send it to Televue service, I'm from Europe, it eould be not a great situation, so I want to try to clean it myself.

[Cielo_nocturno]

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[CrazyPanda]

I have not disassembled a Delos, but I have several different eyepieces.

 

To disassemble an eyepiece you need an adjustable spanner wrench. The retaining ring is likely glued in with some kind of optical cement so it can take some force to pop it loose. If you're not careful, this can cause the spanner wrench to slip and you can scratch a lens. Care has to be taken.

 

You'll also need a small suction cup to pull the lenses out, or you need to push the stack out of the eyepiece from the eye lens and then remove one lens from the stack at a time. This is my preferred method since suction cups can let go and you can drop the lens or it can land back in the eyepiece in a way that you don't know which orientation it was supposed to be in. Suction cups also leave a residue on the lens surface that has to be cleaned, and it's very, very hard to properly clean a lens to the point where there is no debris left on it. Best to avoid having to touch any internal lens surfaces if possible.

 

The key is to diagram the lenses and spacers (shape and orientation) as you remove them so you know what order they go back in.

 

I will say this though - getting them perfectly clean and dust-free as they go back in is a lot harder than it looks. You really need a clean air enclosure providing positive pressure, and you need lint-free cleaning materials. Regular kimwipes or cotton swabs usually aren't sufficient ans will always leave particles behind.

Edited by CrazyPanda, 14 April 2025 - 08:00 AM.

[Rigel_10]

I'm not positive but I believe fungus is difficult to remove especially as much as in your eyepiece. Plus the whole eyepiece is probably infected with spores so the whole thing would probably need to be cleaned thoroughly and even then who knows?

That's why EPs like explore scientific have an edge with the argon gas that prevents fungus from ever growing in the first place.

Good luck, it will be interesting to see what the solution is?

[Tom Masterson]

Contact TeleVue. They clean/repair their eyepieces. I sent any eyepiece to them for repair many years ago.

 

If you take it apart, and it is indeed fungus, it's likely the coating is damaged, and at worse, the glass surface itself etched, so cleaning won't "fix" it.

 

I had a little on the inside surface of one of my doublets. Cleaning helped a little bit, mostly at the margins of the growth, but the damage to the coating was done. In my case, it's a tiny spot that has no impact on the image.

 

Good luck.

[T1R2]

If its on the outside of the lens clean it with a q-tip with a couple sprays of lens cleaner like Zeiss Lens Cleaner to the swab, not the lens, then use 91%- 99% alcohol also on a q-tip but don't over saturate the swab, just 2-3 drops or light dip of the q-tip in about halfway. then clean it with a slow circular motion from center to edge , then finish off with a q-tip and acetone, this is the important part, make sure the q-tip swab is saturated, you can either dip the head in/ out (do not hold it in there and soak it) of a small amount in a shot glass or stainless steel condiment cup, or if you have one of those .5-1oz amber tincture bottles with the little nylon dripper stopper you place the q-tip on the dripper and turn the bottle upside down until you see the the entire head swell and get shiny, then its properly loaded and you can stop saturating the swab. apply it in the same manner, clean in a circular motion from the center of the lens to the edge, and don't take too long, it should take about 10sec to do the circular motion from center to edge, because you do not want the acetone to evaporate too much or else it will streak, but its fine if it does , just get a new swab and re-dip it and go over the streak marks with fresh q-tip and only take about 10 sec again to clean the entire surface on the lens. 

[Mike W]

I'm not positive but I believe fungus is difficult to remove especially as much as in your eyepiece. Plus the whole eyepiece is probably infected with spores so the whole thing would probably need to be cleaned thoroughly and even then who knows?

That's why EPs like explore scientific have an edge with the argon gas that prevents fungus from ever growing in the first place.

Good luck, it will be interesting to see what the solution is?

Oh come on! I have 30 year old TV eyepieces with no fungus. Don't put them away wet.

[T1R2]

Oh come on! I have 30 year old TV eyepieces with no fungus. Don't put them away wet.

That was my guess as well, they used the EP on a cool night for a long time until the EP was really cool, then capped it and put in back in the case and brought it in without opening the case and lifting up the caps a little and let them air out for several hrs. . This always ends in disaster.  

[Mike W]

It's the same with binoculars, my Nikon 8X42 MHG I have now are the first bins waterproof I've ever had. All my previous bins no issue, I never put them away wet, when they warm up I pull the caps and leave them open and out of the case for 24hrs. NEVER had any fungus!

[CrazyPanda]

Oh come on! I have 30 year old TV eyepieces with no fungus. Don't put them away wet.

 

Being put away "dry" is no guarantee of safety.

 

I've had optical fungus attack:

• 35 Panoptic
• 2x PowerMate
• 17 ES92

All stored dry.

 

I received a 32mm Takahashi Abbe ortho brand new in box with optical fungus growing on the field lens.

 

These are the conditions in which fungus will grow:

• 65% humidity for at least 3 days
• Darkness
• Little to no airflow
• Source of nutrients (dust etc)

 

Here in New England during July, August, and September it's not uncommon for relative humidity during the day to be in the mid to high 70s (or even 80s) for days or weeks on-end.

 

If you put an eyepiece away dry but in a case where the RH in the case is 75%, then the environment is not actually dry even if there isn't any actual liquid condensation on the optics. If there are fungal spores on the surface, they can grow in that environment.

 

Ever since I've kept a hygrometer in the case and have been diligent about keeping fresh silica gel in the case, I haven't had any problems with fungus. Though some eyepiece caps can seal too tightly against the rubber eye cup and even if the case environment is dry, the environment around the lens is not, and it still runs the risk of fungus growing.

[T1R2]

Being put away "dry" is no guarantee of safety.

 

I've had optical fungus attack:

• 35 Panoptic
• 2x PowerMate
• 17 ES92

All stored dry.

 

I received a 32mm Takahashi Abbe ortho brand new in box with optical fungus growing on the field lens.

 

These are the conditions in which fungus will grow:

• 65% humidity for at least 3 days
• Darkness
• Little to no airflow
• Source of nutrients (dust etc)

 

Here in New England during July, August, and September it's not uncommon for relative humidity during the day to be in the mid to high 70s (or even 80s) for days or weeks on-end.

 

If you put an eyepiece away dry but in a case where the RH in the case is 75%, then the environment is not actually dry even if there isn't any actual liquid condensation on the optics. If there are fungal spores on the surface, they can grow in that environment.

 

Ever since I've kept a hygrometer in the case and have been diligent about keeping fresh silica gel in the case, I haven't had any problems with fungus. Though some eyepiece caps can seal too tightly against the rubber eye cup and even if the case environment is dry, the environment around the lens is not, and it still runs the risk of fungus growing.

Yes, its not good to leave them in a humid environment for long periods of time like a garage/ shed / observatory in England or the PNW, for the best protection they should always be stored inside a dry climate controlled environment. 

[denis0007dl]

Correct: dry climate controlled environment.

And avoid plastic hermetic closed cases, they serves just for transport.

[Mike W]

Being put away "dry" is no guarantee of safety.

 

I've had optical fungus attack:

• 35 Panoptic
• 2x PowerMate
• 17 ES92

All stored dry.

 

I received a 32mm Takahashi Abbe ortho brand new in box with optical fungus growing on the field lens.

 

These are the conditions in which fungus will grow:

• 65% humidity for at least 3 days
• Darkness
• Little to no airflow
• Source of nutrients (dust etc)

 

Here in New England during July, August, and September it's not uncommon for relative humidity during the day to be in the mid to high 70s (or even 80s) for days or weeks on-end.

 

If you put an eyepiece away dry but in a case where the RH in the case is 75%, then the environment is not actually dry even if there isn't any actual liquid condensation on the optics. If there are fungal spores on the surface, they can grow in that environment.

 

Ever since I've kept a hygrometer in the case and have been diligent about keeping fresh silica gel in the case, I haven't had any problems with fungus. Though some eyepiece caps can seal too tightly against the rubber eye cup and even if the case environment is dry, the environment around the lens is not, and it still runs the risk of fungus growing.

I run a de-humidifier in my house don't you?

[Rigel_10]

Oh come on! I have 30 year old TV eyepieces with no fungus. Don't put them away wet.

Mine don't get wet in the first place. and I've never had an eyepiece with fungus in it but I have had two pairs of binoculars with fungus.. when I discovered it I just throw them out so they don't affect anything else.

[CrazyPanda]

I run a de-humidifier in my house don't you?

Only when the humidity gets to an unbearable level. Too expensive to run the mini splits all the time.

[Ernest_SPB]

So many messages and not explicit answer to starting question!

 

Fighting with fungus is rather complex and different from normal cleaning procedure: https://petapixel.co...e-fungus-lens/  and https://richardhaw.c...ungus-cleaning/

 

It requires disassembling.

 

My answer: at first - contact TeleVue (phone call) and ask their instructions what to do. 

Edited by Ernest_SPB, 15 April 2025 - 12:16 AM.

[Mike W]

Only when the humidity gets to an unbearable level. Too expensive to run the mini splits all the time.

Not A/C, de-humidifier. Also buy a cheap humidistat. Here in the northeast we get long periods of rain and too cold to run A/C. The de-humidifier also keeps the house feeling warmer. If you wait until the humidity gets to an unbearable level you are way behind the eight ball! Also if you keep the hum. down you can run A/C less. Back to the topic. 

N.A.T.E. certified HVAC technician.

 

https://www.amazon.c...1zcF9hdGY&psc=1

Edited by Mike W, 15 April 2025 - 10:25 AM.

[CrazyPanda]

Not A/C, de-humidifier.

 

My mini-splits have a dehumidifier mode. I never run them as AC unless temps are in the mid 90s. Simply dehumidifying things makes warm temps feel fine, but even then it still costs money to keep them constantly dehumidifying so I don't do that often.

Besides, I don't keep my eyepiece cases in the house. They stay in an insulated room in my garage. The only time they come into the house is when I need to clean the eyepieces.