advice on cotton wool for cleaning my SCT & Mak corrector plate etc

[RT65CB-SWL]

Hi all.

Any advice on cotton wool for cleaning my SCT & Mak corrector plate and refractor objective, (and my other optical hardware too).

I read somewhere that 'surgical' cotton wool (ie branded 'BP') is/was recommended.

So one day last week, I wasted about a total of two and half hours, touring local supermarkets chemists/drugstores trying to locate the elusive 'BP' branded cotton wool.

I gave up yesterday and purchased a bag of supermarket own budget brand brand, non-'BP', 300 cotton wool balls.

Will they be any good?

PS - Any advice on cleaning them too most welcome! - thank you.

[DirkSteele]

Televue have a nice page on cleaning telescope optics.  http://www.televue.com/engine/TV3b_page.asp?id=103

As for the cleaning fluid itself, I recommend Baader Optical Wonder Fluid.  http://www.firstlightoptics.com/misc/baader-optical-wonder-fluid.html

Please note that the wonder fluid is not suitable for mirrors and is primarily for EPs (as you mention other optical hardware as well)

Clear skies,

[Peter Drew]

I use BP branded cotton wool balls for cleaning optics including my 16" SCT's with good results. I have used unbranded without problem but would prefer BP as there is more chance of unwanted inclusions.

[pete_l]

Hi all.

I read somewhere that 'surgical' cotton wool (ie branded 'BP') is/was recommended.

PS - Any advice on cleaning them too most welcome! - thank you.

I can't see why you'd need surgical grade. The only difference (I beleive) is that it would come in a sterile package. Just make sure that when you open your pack of c/w you close it up after you take each piece, and don't put anything back in. The reason is that will stop any small, abrasive, particles getting into the c/w. Although it's very unlikely, and glass is quite a hard material, it's generally a good move to try reduce the chances of scratching the optics - although if you do scratch them, it's not the end of the world.

People do have a tendency to go completely overboard with their recommendations. One person says you *must* use this-or-that, so the next person tries to top that by saying you MUST use something even more expensive. I've heard of people cleaning very expensive optics on a 25 inch Dob with a pair of underpants¹, so I doubt it would make much difference what you use, so long as it's not sandpaper.

The usual advice about cleaning your optics is: don't. They have to be particularly dirty before they start to have any effect on the view you'll see.

[1] Link to the underpants story. (It also involved a hosepipe and some shampoo) PDF file, Page 25

http://tinyurl.com/pkhjxng

[Oddsocks]

"BP" is not a brand, any medicine or product carrying the "BP" label it means it conforms to the requirements laid out in in the journal British Pharmacopoeia which is a like a recipe book for surgery and medicine.

"BP" cotton wool should be 100% pure cotton and supplied in sterile sealed packs and for this reason is more expensive than "normal" cotton wool used for domestic purposes.

The stuff most pharmacies sell that is marked for medicinal use should be ok, avoid the cheap cotton wool that is used for make-up removal and general use as this may contain traces of abrasive dust and other fibres.

This thread asks the same question:

http://stargazerslounge.com/topic/78403-anyone-know-where-to-get-bpc-cotton-wool/

William.

[Bizibilder]

As above but non-BP can also contain man made fibres etc that are quite capable of scratching the coatings of lenses and the reflective surfaces of mirrors.  If you stick with "BP" you should be OK.  I believe Boots sell it (well they did about 5 years ago!!).

[RT65CB-SWL]

The only reason for me asking is/was that I am/I was going to remove the majority of the grime before the Baader Optical Wonder Fluid.

I don't fancy messing up the coatings of the main cell(s) with scratches to the coatings etc. 

[Oddsocks]

When I cleaned my primary and secondary mirrors earlier this year I just soaked them for a twenty four hours in a bowl of warm water with a little dish washing detergent then rinsed off under a fast running tap for ten minutes.

Most of the water beaded up and dropped off the mirror and there were no stubborn deposits left so no need to attack it with cotton wool or anything else.

Then I made a big mistake, I wanted to make a final rinse with distilled water and had bought a hand spray bottle from B+Q which I had washed and rinsed well, filled with distilled water (not de-ionised water which is something completely different), and sprayed the mirrors with copious amounts of distilled water and the final result? great ugly streaks and white stains all over the mirrors...aaarrgghhh.

It seems the inside of the bottle was coated with a water resistant injection mould release agent which felt like silicone oil, anyway it wouldn't wash off the mirrors or clean off the bottle so the bottle went in the bin.

I then had to buy with great difficulty a couple of litres of 100% Isopropyl Alcohol, re-soak the mirrors in several changes of the IPA for a couple of hours and then wash with plain tap water and detergent again several times before the marks disappeared. This time I didn't bother with the distilled water and just dried the mirrors by touching the water beads with a little tissue paper to soak them up without putting any pressure or rubbing the mirror.

Still.....I shall know next time!

William.