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Hemi,
Sorry I only just saw this post this evening; I live in Cairns & recently experienced what appeared to be small mould blooms on the inside of my Meade SCT Corrector Plate. I cleaned it myself after much research, thought & after two months of working up the courage... I'd not done anything like it before.
First thing to make sure of: Humidity level below 60%.. I know this is tough in the tropics but, if you don't wait for a day where humidity is low, you will just trap a bunch of warm, moist air in your OTA... & you'll be back with mould in no time...
I made up a cleaning solution from a recipe I found on about half a dozen professional observatory sites; the recipe is as follows:
45% demineralised water
45% Isopropyl Alcohol (99 - 100% pure)
10% Windex brand only window cleaner (available in supermarkets)
5 drops of organic, non scented washing up liquid
Then, mark where your corrector plate sits using masking tape so that is goes exactly back where it was, carefully remove retaining ring & then carefully remove corrector plate. Removing the corrector plate may not be as simple as it sounds; I ended up having to use a carefully padded allen key to break the seal that had formed between the glass & the foam like cushion the glass sits on.
I used a couple of folded up clean cloth nappies to place my corrector plate on so that it was sitting on something soft whilst I cleaned it.
To clean, wear either lint free cotton gloves or powder free latex gloves. First step, take a Lens blower (Puffer) & blow off any dust.
Next, get a brand new camel hair makeup brush & lightly brush your optics to remove any remaining dust.
Next using either kimtech wipes or (again from an observatory site) Plain White Kleenex brand tissues. Carefully fold the tissue into a triangle, dip one edge into the cleaning solution so that it is damp, not ringing wet & wipe a small area from centre to outer using the weight of the tissue only, no force, no pressing: dispose of tissue, select new one & repeat, working your way around the corrector plate carefully.
Next, using a mix of 50% distilled water & 50% Isopropyl alcohol, repeat the process using a clean tissue each time; this is the rinse cycle.
Then, using a dry tissue, carefully wipe in the same manner to dry any residual moisture. Same method of tissue use, no pressure is used throughout.
Finally, once dry, blow with lens puffer & then last go over with camel hair makeup brush...
Before reassembling, look for any major dirt on primary/secondary mirror, dust inside the OTA, etc... only clean if absolutely necessary but, definitely blow dust out of OTA.
Reassemble carefully ensuring that your corrector plate is correctly aligned with the marks you made before you removed it... Take outside, collimate as required....
With a couple of go overs, my mould blooms were gone.. mirrors were dusty so got blown & brushed lightly but, that was all. Tube of OTA was a little dirty so it got blown, brushed & some minor cleaning.
Amazingly, my scope was pretty damn close to collimation when I reassembled & star tested... despite putting a fair amount of pressure on the secondary assembly initially trying to remove the corrector plate... Couple of tweaks (1/16th of a turn on one screw) & it was back in collimation...
I am now about 8 months on, no mould has returned, optics are beautifully clean and the views are good when there is no cloud.
I don't store my scopes outside but, inside the house in a well ventilated room (fan going all the time)... I'm paranoid about mould & have been investigating potential prevention techniques but, found nothing practical & suitable as yet. I do not put covers, lens caps or close boxes after a nights viewing.. I open everything up, point my OTA down & allow everything to dry thoroughly before EP boxes, etc.. get closed..
I had never done or contemplated doing this to any of my scopes before but, I watched countless videos, read countless procedures, took a deep breath & gave it a crack... it worked & on reflection, wasn't that hard.. just be careful when screwing the retainer ring back on.. it just has to be lightly firm not done up hard tight...
Hope this helps, good luck with your mould or oxidisation issue, hope you are able to end up with the result I did..
Cheers
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