Fungus - To remove or not to remove

[Lee]

Assuming a typical 8" SCT Front Corrector Lens & Main Mirrror which had been infected with stubborn fungus for years. Assume they are more than 10 big fungus spots of about 2-3mm and more smaller ones around the peripherals. These fungus cannot be remove with typical optical cleaners Alcohol base cleanser.

Now I got a a powerful Alcohol base cleaner (MEK) which can remove almost any debris & marking even fungus on the Lens & Mirror. (had used that to remove the most stubborn dirt on my car!)

Should I then use this to remove all the Fungus infected spots on the Lens & Mirror knowing :-

- it will remove all optical coating on the lens & mirror
- it might also remove the mirror base Al coating

Or should I just let the fungus stays & spreads further :roll:

What is the expected optical loss/gain ?

[kayheem]

Are you sure it will remove the coatings as well? I know the multicoatings on the corrector plate is quite tough.

You can try a small spot first. If the coatings are affected, will need to be sent back for re-coating.

Kay Heem

[rlow]

Hi Wee Kiong,

Having cleaned out more than half a dozen different SCTs with fungus before, I think you should still clean it and not let it get worse. I use a mild non-alcohol cleaning solution. I can take a look and help out if you like.

[Lee]

Hi Wee Kiong,

Having cleaned out more than half a dozen different SCTs with fungus before, I think you should still clean it and not let it get worse. I use a mild non-alcohol cleaning solution. I can take a look and help out if you like.

Just a sidetrack, remember the German School we went last time, next Thursday evening will have another. Interested ?

[rlow]

sure Wee Kiong, preferably if you can pick me up. If you have space, I can bring the 210 & sphinx, otherwise just a c5. thanks!

[echelon]

Assuming a typical 8" SCT Front Corrector Lens & Main Mirrror which had been infected with stubborn fungus for years. Assume they are more than 10 big fungus spots of about 2-3mm and more smaller ones around the peripherals. These fungus cannot be remove with typical optical cleaners Alcohol base cleanser.

Now I got a a powerful Alcohol base cleaner (MEK) which can remove almost any debris & marking even fungus on the Lens & Mirror. (had used that to remove the most stubborn dirt on my car!)

Should I then use this to remove all the Fungus infected spots on the Lens & Mirror knowing :-

- it will remove all optical coating on the lens & mirror
- it might also remove the mirror base Al coating

Or should I just let the fungus stays & spreads further :roll:

What is the expected optical loss/gain ?

You should try to remove the fungus if possible. I myself cleaned my Celestar 8 the other day, it had some fungus after being mothballed for nearly 4 years.

By the way, wear gloves when handling MEK, its carcinogenic.

[kayheem]

Not sure if it is carcinogenic, but do please put on proper PPE (Personal Protective Equipment) and do it in a well-ventilated place.

The material safety data sheet (MSDS) is here:

http://ptcl.chem.ox.ac.uk/MSDS/BU/2-butanone.html
http://www.temarry.com/MSDS/Methyl_Ethy ... e_msds.htm

Please read before using.

Kay Heem

[Airconvent]

Hi
Most of you report on having fungus on your optics.
Don't you all keep your stuff in a dry box?

BTW, once cleaned , can the optics be none of the worse? or can we expect a visible degradation in visual performance?

btw off topic here, Echelon, are you the same echelon from ppcsg.com?

cheers

[acc]

You won't notice a visible difference in visual performance as the degraded optical surfaces are just a very small percentage of the overall area. Note how big the central obstruction of an SCT is (assume its a huge fungus on steroids) and yet, it still serves up decent views!

[VinSnr]

Assuming a typical 8" SCT Front Corrector Lens & Main Mirrror which had been infected with stubborn fungus for years. Assume they are more than 10 big fungus spots of about 2-3mm and more smaller ones around the peripherals. These fungus cannot be remove with typical optical cleaners Alcohol base cleanser.

Now I got a a powerful Alcohol base cleaner (MEK) which can remove almost any debris & marking even fungus on the Lens & Mirror. (had used that to remove the most stubborn dirt on my car!)

Should I then use this to remove all the Fungus infected spots on the Lens & Mirror knowing :-

- it will remove all optical coating on the lens & mirror
- it might also remove the mirror base Al coating

Or should I just let the fungus stays & spreads further :roll:

What is the expected optical loss/gain ?

Please dun use that on the mirror and lens.