I have a fungus problem

[symmetal]

My ETX-125 hasn't been used for a good many years. The declination got very sloppy through having tried to attach cameras to it before lightweight astro cameras were around. For the last few years it's been in its foam lined case in the shed. I thought I'd de-fork it and mount it on an eq3 pro synscan with tube rings for planetary viewing and imaging.

All went well until I took the dust cap off, and found spidery growths on the corrector plate. I unscrewed the corrector plate according to Weasner's ETX site and removed them with microfibre cloth dipped in isopropyl alcohol. Unfortunately the secondary mirror has also been infected. I believe it is the UHTC coated optics version

I had to rub the corrector plate firmly to remove the fungus but am reluctant to do that on the mirror.  

Does anyone have any suggestions as to what might be done to remove them from the secondary? I've attached two pictures of the outside of the plate before cleaning and the secondary. Luckily the main mirror looks shiny and spotless.

Thanks for reading.

[nightfisher]

Your best getting it cleaned of, as its doing damage while its present, i have cleaned the secondary on maks and had no problem with them

[ronin]

Can only suggest ideas but I would start with a soft artists paint brush - camel hair I think is the description, why I have no idea, and brush very carefully with IPA.

The hope is that the silvering is coated/protected and that the fungus gets removed. Then examine it again and decide if further action is required. If it is then my approach would be to brush again with IPA and then gently rub with a cotten wool bud also soaked in IPA. Just be careful of how much pressure is applied. My concern is how easily the reflective coating may be removed. Suspect that as it is internal then there was not a great amount of consideration applied to a protective coating. Some yes but not a lot. However Meades tend to be reasonably well constructed.

That is my thoughts, whether correct or useful I have no idea.

[mikeDnight]

Mirrors can be cleaned using sterile water and a cotton ball. 

I'd be inclined to keep the scope in the house when not in use and leave it uncapped at both ends over night to allow any moisture to evaporate.

Mike

 

[symmetal]

Thank you for the helpful replies.

I  put a few drops of IPA in the funnel formed by the baffle and used cotton balls to gently wipe over the fungus. It took several repeats to eventually remove it by which time the IPA had partially dissolved the glue on the double sided tape ring holding the baffle in place. With the baffle removed it was easier to access but getting the remaining glue off was a long job. Finished off with distilled water but there is a trace of the fungus outline still visible on the secondary so it seems to have damaged the coating. I'll put it back together and see how it performs.

[Alien 13]

Fungus is nasty it will eat coatings and glass, I have no idea how to kill it so any of my lenses that have shown signs have been thrown away because the spores will spread to any optics nearby. The only effective prevention I know of is regular exposure to some UV.

Alan

[symmetal]

Alien 13 - On the CN forum some have recommended using hydrogen peroxide to kill off the fungus on the corrector plate but I'm not sure what it would do on a mirror. I've been leaving the main mirror exposed to sunlight with the scope end covered with a plastic bag with desiccant bags inside while the corrector is off to hopefully kill off any which might be lurking. The main mirror looks fungus free luckily. 

[Alien 13]

29 minutes ago, symmetal said:

Alien 13 - On the CN forum some have recommended using hydrogen peroxide to kill off the fungus on the corrector plate but I'm not sure what it would do on a mirror. I've been leaving the main mirror exposed to sunlight with the scope end covered with a plastic bag with desiccant bags inside while the corrector is off to hopefully kill off any which might be lurking. The main mirror looks fungus free luckily. 

Sunlight is a great help, I make sure now that all my scopes/lenses are never locked away from the light.

Alan

[Alien_Photons]

Its a pain to get rid off and the truth is if its in you lens/mirror its also already all over your scope. It will come off, but it causes damage, hopefully its not gone that far, thankfully it if caught early will have little effect.

Most of us learn the hard way.

The shame of it is its avoidable and we don't do enough to educate ourselves or each other from day one about this problem.

 

[symmetal]

 

13 hours ago, Alien_Photons said:

Its a pain to get rid off and the truth is if its in you lens/mirror its also already all over your scope.

That's true although everything and everybody exposed to the air will be covered in fungal spores. Stopping them germinating is the key. 

On 15/04/2017 at 01:10, Alien 13 said:

Sunlight is a great help, I make sure now that all my scopes/lenses are never locked away from the light.

My FLT-98 on the pier is in a small windowless plastic roll-off shed with a 60W tube heater on the floor when the humidity is high and I run a de-humidifier for a couple of hours if the scopes been out and got dew on it.

I have a UV light source which I used to use to erase EPROMS when they were widely used in computer programming 20-30 years ago. Do you think it's worth running it in the shed for a few hours at a time periodically. The normal 'blacklight' UV tubes you buy are the wrong wavelength and intensity to affect fungal spores but this one stings your eyes if you just glance at it so it could make the fungus very uncomfortable. Pointing the scope at it would irradiate the inside. Best to remove the camera first though. Pause for thought.