Fungus growing on filters and snapping zwo filter clips, what to do?

[pipnina]

I noticed a strange vignette on my halpha filter during the last imaging session, and shon a torch down the tube to see if it were a spider or some such. Horrifyingly I saw spiderweb like fungus had grown to cover a sizable portion of the filter. I images RGB that night but the other day I opened the filter wheel to see Multiple filters affected, red in particular but none as severely as the halpha. On chroma's website they say acetone or pure alcohol is suitable but while my acetone did remove fungus from one filter, it left a misty haze behind and so I stopped in case the impurities caused further issues!

 

During this operation multiple filters seemed to have snapped or cracked retainer rings. I have to  admit they looked cheap rubbish when I installed them from the zwo kit but I didn't expect to find £3000 worth of chroma filters held in by the screws alone...

I don't seem to have any spare clips so if they're available I will have to find replacements I suppose, as I will need to remove the filters properly to give them the thorough delicate clean they need to avoid damage but I can't reasonably put them back with broken retaining clips.

My next idea was to use distilled water from my film development station, which is very good stuff and leaves my negatives in pristine conditions of cleanliness as the final rinse. Pipetting it onto the filters to cause remaining dirt or residue to rinse off.

Maybe using the acetone or a more pure acetone or alcohol would be better?

 

At the same time I have to find a way to remove dried super glue from a panic repair to my EAF bracket that spilled onto the filter wheel. Acetone seems to dissolve it but so slowly I'd be there all year. I am terrified of damaging the paintwork and am trying to avoid scraping or sandpaper...

 

Oh dear oh dear. I've often cursed myself for buying chromas instead of far cheaper but nearly identical Baader or Astronomik but now with fungus issues I'd really really rather have cheaper filters that would be less stressful to clean!

Thanks in advance for advice!

James

[Adam J]

9 hours ago, pipnina said:

I noticed a strange vignette on my halpha filter during the last imaging session, and shon a torch down the tube to see if it were a spider or some such. Horrifyingly I saw spiderweb like fungus had grown to cover a sizable portion of the filter. I images RGB that night but the other day I opened the filter wheel to see Multiple filters affected, red in particular but none as severely as the halpha. On chroma's website they say acetone or pure alcohol is suitable but while my acetone did remove fungus from one filter, it left a misty haze behind and so I stopped in case the impurities caused further issues!

 

During this operation multiple filters seemed to have snapped or cracked retainer rings. I have to  admit they looked cheap rubbish when I installed them from the zwo kit but I didn't expect to find £3000 worth of chroma filters held in by the screws alone...

I don't seem to have any spare clips so if they're available I will have to find replacements I suppose, as I will need to remove the filters properly to give them the thorough delicate clean they need to avoid damage but I can't reasonably put them back with broken retaining clips.

My next idea was to use distilled water from my film development station, which is very good stuff and leaves my negatives in pristine conditions of cleanliness as the final rinse. Pipetting it onto the filters to cause remaining dirt or residue to rinse off.

Maybe using the acetone or a more pure acetone or alcohol would be better?

 

At the same time I have to find a way to remove dried super glue from a panic repair to my EAF bracket that spilled onto the filter wheel. Acetone seems to dissolve it but so slowly I'd be there all year. I am terrified of damaging the paintwork and am trying to avoid scraping or sandpaper...

 

Oh dear oh dear. I've often cursed myself for buying chromas instead of far cheaper but nearly identical Baader or Astronomik but now with fungus issues I'd really really rather have cheaper filters that would be less stressful to clean!

Thanks in advance for advice!

James

Well for a start they are not nearly identical. I have recently seen results that show better contrast from chroma 8nm than Antlia 3nm filters. 

Chroma 8nm Ha, 5nm Sii/Oiii vs Antlia 3nm SHO 50mm round filters - Experienced Deep Sky Imaging - Cloudy Nights

But in any case you need to get it off as it fungus can be acidic and will etch the filter coatings if you don't get it off sharpish. 

I would use what you have, acetone is recommended and you have some so use that, then wash it off with distilled water after that. 

Don't worry about little water marks for now, just get the fungus off ASAP and worry about that later.  

I personally use pure cotton buds to wipe the surface, the important thing it is to keep rotating the bud and use many many buds so your lifting the stain from the surface not just moving it about. 

Adam 

Edited February 20 by Adam J

[Adam J]

Also Wipe the ENTIRE filter wheel down it will be full of spores and you want them all dead. 

Adam

[Elp]

Exposure to a UV lamp is used to clean camera lenses for the initial fungal growth, as is the sun but the heat exposure to sunlight can be an issue on non glass parts. It's the UV you need to bathe each side of the surfaces. Then wipe afterwards with some chemical like diluted peroxide but check it doesnt mess with any coatings first. I've cleaned an old lens by taking the front objective out, cleaning with white vinegar then leaving in sunlight for a few hours, then finishing with a lens cleaner before reassembly.

Edited February 20 by Elp