Spots on refractor lens - to clean or not?

[pjspur]

Hi,

My new WO GT81 refractor has quite a few spots on the lens that look like the result of dew drying and leaving a residue. Having had a bad experience cleaning a lens in the past I really dont fancy trying again.

Are they likely to have any impact on the scopes performance (its mainly used for imaging)? As far as I am aware it could have some impact on contrast but dont know how much or if it would affect imaging at all.

If they are best removed, does anyone have any suggestions where/how to get it professionally cleaned (would sending it to WO be the best, if expensive approach for example)?

Thanks,

Paul.

[quattrorings]

Quite a few people on this site recommend Baader Wonder fluid cleaner with the special microfibre cloth.

I know FLO sell it. Otherwise many photographic repairers will often do this cleaning.

As with anything if unsure refer to a specialist.

Best of Luck.

[JamesM]

Personally I wouldn't clean it unless you felt the 'residue' particularly bad. However, if you feel that it does need a sort out, you can do this yourself by observing some small steps. First, under a decent light source, make sure that you use a small blower (photographic shops sell them cheap) to blow away any surface grit/particles that might be sitting on the surface. Second using a small soft brush, lightly brush from the centre of the objective lens towards the outside, working your way around until the whole objective has been swept. Then using some Baader Wonder Fluid (FLO or Rothervalley Optics) apply some solution to surgical cotton wool (particles aren't left behind) and again starting from the centre, clean the glass using one stroke towards the outside. Ensure that a fresh piece of cotton is used for one stroke only and then dispose of it. Repeat until the whole surface is cleaned.

I know what you'll be thinking, it all sounds a bit too complicated and that you are frightened to do it in case you mess it up. Perhaps the way I've written the above might seem a little laboured but its all very simple really and doesn't taken long. Just take your time and work under a good light. The fluid evaporates off leaving no smears so there will be no need to polish the glass afterwards. I use this procedure on my 6" refractors when needs must and its not a big deal - just take your time. :)

Clear skies

James

(Edit - sorry Quattro rings replied as I was typing!)