To clean or not to clean...?

[huwbellamy]

I have been storing my C6R frac big end down. I noticed yesterday there is a little dust settling on the inside surface of the objective. Do I worry about this or is it generally not a problem. I am a devil for cleaning lenses (comes with the job) but I will leave it well alone if aomeone tells me firmly enough.

I'm storing it objective up now. Thanks, Huw.

[James]

Is there any evidence of the dust spoiling the view at all? If not I'd leave well alone. Aside from the possible risks in cleaning there's the potential or affecting the collimation of the scope if you have to remove the objective for cleaning.

My scopes mirror has a nice accumulation of dust unfortunately but I can't see any difference in the views I'm getting. I'm still having a problem restraining myself from cleaning it though...

[barkis]

If the dust you see is on the outside of the inside lens, if you know what I mean, then removing the whole lens cell could be done without upsetting the collimation. Collimation upset would not be the big danger, that would be the misalignment of the two lens elements, if it is a doublet that is. The screws that hold the complete cell in the scope should be identifiable, and only those should be extracted, allowing you to draw the cell from the tube. On no account touch any of the others. A quick look at the rear lens should tell you if the dust is deposited there, in which case it could be removed by blowing air over it, followed by a proprietary lens cleaner. If the dust is on the inside of the lens, I would wonder how it got there, then leave it. Perhaps storing the scope in an inverted position has it's merits, but not if you leave protective caps off the drawtube aperture. If you do remove the lens cell, be sure to mark one screw hole on the cell and the tube so that it goes back the same position. If in any doubt about doing this task, don't.

Ron.

[Greg]

If you can take the complete lens cell out and clean then inside with Baader Optical Wonder Fluid..then that's fine..

http://www.firstlightoptics.com/proddetail.php?prod=wonderfluid

Most lens cells unscrew in one complete unit from the tube.

As it's you ....Here's my 120 frac lens cell in bits..it's a fine thread so be a bit careful screwing it back onto the tube..

The lens has to be pretty dirty to interfere with the seeing..If in doubt..LEAVE ALONE!!

[huwbellamy]

Thanks all,

I removed the cell that is held by three screws (I marked one so as to reorientate properly). The dust inside came off with a blower (clean washing up liquid bottle - nice big puffs, my camera puffer thing is hopeless).

There are some specs of dust within the cell but having read a lot of previous threads I think they're probably best left and of no consequence anyway - just annoying that I know they're there!

I have tried several lens cleaners and find clear meths with a little water and lots of clean tissues to mop up quickly works best for no smearing. I can't comment on the Baader fluid but wouldn't recommend the aerosol cleaner I sell for cleaning spectacle lenses - it's great for small surfaces but dries too quickly on a large lens leaving smears. I also find that even the best quality microfibre cloths leave smears on big lenses and clean, soft tissues work better as they absorb the fluid more quickly.

I wish the clouds would clear so that I could stop messing about with it and start observing, heres hoping....

Huw.