Silver spots on objective lens

[vince 66]

I have noticed that I have lots of tiny silver spots on the lens of my Megrez 90 some look like pieces of glittter. I have to admit that this is starting to worry me as I have only had the scope for 12 months and I don't want to start cleaning the lens to much does any one else have this problem or know the cause .

[NGC 1502]

Any chance of a pic please ? Ed.

[vince 66]

I'll try but I don'tt think a photo will show them.

[dobbie]

You got a photo of your lens , are the silver dots on the outside or in bit of a puzzle this one.

Sent from my HTC Wildfire using Tapatalk

[vince 66]

They appear to be on the outside I have just taken some photos but the lens looks perfect so they don't show anything.

[michael.h.f.wilkinson]

Maybe some droplets of liquid got on the lens and dried up. This can leave a residue that cancels the effect of the coating, which makes them appear bright. This will affect the contrast of the image slightly. There may be a simple way to clean the lens (with proper optical tissues!!), but it does depend a bit on the nature of the residue how best to remove it.

[AndyH]

I had a similar effect on my apo. Think it was left after a dewing incident. I simply cleaned it as normal with a cloth and fluid. Turned out A-OK.

Andy.

[Moonshane]

I think people worry too much about cleaning glass optics (mirrors are different). the coatings are very much hard enough to stand careful cleaning as long as you remove any hard grit etc then I am sure you'll be fine and after you've done it wonder what all the fuss was about.

[A McEwan]

This sounds like the same thing I had on my 90mm triplet after only a few weeks use. I returned it to be examined by the retailer and they informed me that it was moisture that had dried on the surface and left the spots. Actually they said someone had probably sneezed on it! They cleaned it for me and it was then like new again. If you're hapopy to try cleaning the lens, it might well solve the problem.

HTH,

Ant

[vince 66]

I have Baader wonder fluid and a micro fibre cloth will this be ok or do I need somthing else.

[michael.h.f.wilkinson]

I have Baader wonder fluid and a micro fibre cloth will this be ok or do I need somthing else.

That should be OK, though some prefer optic tissues (I don't)

[AndyH]

Seconded. Not keen on the tissues.

[vince 66]

So are optic tissues already impregnated with a cleaning solution.

[A McEwan]

Baader Optical Wonder, their own cleanin cloth, and follow these instructions to the letter:

http://www.baader-planetarium.com/pdf/opticalWonder-engl.pdf

Works for me!

Ant

[vince 66]

Thanks for all the replies I will give it a go when I have some time is it ok to apply a little pressure when cleaning I have read some articles that say you should only use the wieght of the cloth or soaked tissue.

[NGC 1502]

Thanks for all the replies I will give it a go when I have some time is it ok to apply a little pressure when cleaning I have read some articles that say you should only use the wieght of the cloth or soaked tissue.

I'd say don't use pressure, just the weight of the cloth. Don't forget

to add the fluid to the cloth, not to the lens first, as its possible

for the fluid to creep around the lens edge if done that way.

You may need more than one try to make a nice job. Don't obsess

over perfection ( like I used to ) Just get it as best you can, then

relax !

Best regards, Ed.

[brantuk]

Avoid pressure wherever possible. Tint bits of imperceptible debris can scratch glass, and on mirrors it can destroy coatings

[vince 66]

Well I've just done it the spots have gone all bar one I can now see some streaks on the lens looks like where the fluid has dried I dont want to try to remove these unless some one has a sure fire way of doing it are streaks normal after cleaning or have I applied the cleaner wrong I done it by spraying onto the cloth and then wipeing.

[NGC 1502]

Well I've just done it the spots have gone all bar one I can now see some streaks on the lens looks like where the fluid has dried I dont want to try to remove these unless some one has a sure fire way of doing it are streaks normal after cleaning or have I applied the cleaner wrong I done it by spraying onto the cloth and then wipeing.

Sounds like you are making progress and the spots are nothing

serious, just annoying.

The streaks are maybe whats left of the spots smeared out, or dried

dried cleaning fluid. If it were me, I think I'd have another carefull

try. It's definitely best to apply the fluid to the cloth. But as I've

said, don't obsess like I used to, just do the best you can, and

then relax.

If the spots now look different to when you started to

clean them off, then it shows they are not permanent

Best regards, Ed.

[vince 66]

Thanks for all the advice I do tend to obsess about optics I think I will leave it as it is for now there are some streaks still there but I don't think they will make any difference at first glance the objective looks perfect I think part of the problem is because of the bad weather of late I tend to tinker about with my astro gear when bored which involves alot of looking through my scopes from the wrong end which means if you look hard enough you will always find some little blemish or other to worry about even though it won't affect the viewing at all.