Cleaning refractor objective?

[Miaplacidus]

Hi guys/gals,

Can't figure out how this happened, but somehow a spider got under the objective cover of my Megrez 80 II SD and wove itself a little cobweb on one part of the front lens. I removed the dead spider and the gossamer of the web, but there is a slight residue on the front of the objective and I want to remove it. What's the best and safest way of doing this, short of sending it back to its maker?

All responses greatly appreciated.

Cheers,

Brian.

[astronut]

Hi Brian, Pesky little buggers those spiders!! Use something inert to clean the lens like isopropyle alchohol. First use a blower brush to remove any grit. Then use a clean lens cloth, put a couple of drops of the solution on it and with a gentle swirling action from the middle out clean the lens. Hope this helps. John;)

[acropolite]

Bintel have some cleaning solution that's premixed for cleaning SCT corrector plates. IMO That would be a better option than straight IPA.

[stinky]

Shouldn't IPA be used only when mixed with distilled water?

[Dennis]

If you are using IPA, only use the 99% proof stuff as I have read elsewhere that the less pure stuff contains other ingredients that may leave marks on the lens.

Cheers

Dennis

[Robert_T]

it does... take it from someone who does stuff and thinks later :doh:

[Miaplacidus]

Dear John, Phil, Stinky, Dennis and Robert T,

Thank you for all your responses, and I'm sure they are all correct, even the ones that contradict each other. FWIW, I also sent an email to William Optics directly. In case anyone else is ever afflicted by arachnoscopia, here is their reply:

"Just use plain demineralized water with a cuetip. Whatever it left, it is an
organic substance that will go away with a little bit of water, which will
not harm your coatings."

Thanx again all.

Clear skies,

Brian.

[Miaplacidus]

Just to update people on what to do when a spider makes love to your objective...

Well, the demineralized water didn't work. Just created smudgy smears. The isopropyle alcohol finally did the trick. (I made work for myself, though, by buying a supposed lens cleaning cloth from the pharmacy. Unbeknownst to me, it was impregnated with something like lanolin, which created even more smears than it removed. I finally twigged to what was going on and used an old lint free cotton cloth instead. Took a while, but the objective looks nigh invisible now.) Just praying that I haven't damaged any of the coatings. Need a clear night to test it.

[stinky]

I think demineralized water can also leave a residue - better with distilled water. Around a dollar a litre at the auto shop. Spider excretia is mostly protein - in theory this would be water soluble. In practice - well you gave us the answer!

Duck Smuth sell 99+ % IPA - about $6 for 250ml. I'm using 2/3 water, almost 1/3 IPA and a drop of detergent in a 75ml spray bottle. Be careful not to use too much detergent in the mix if you try it.

Being a fussy specs wearer I go through quite a lot. Certainly does not damage the multi coating on my glasses. I use unscented plain bum paper rolled into a pad and lightly moistened with the solution.

As yet haven't had to clean the objective of my scope - fingers crossed! Good to here your optics are clear!!

Edited as I couldn't type Dikk Smith - shows up as **** Smith