Objective Cleaning issues

[Allan the plumber]

Hi can anyone help "PLEASE"

I recently found my lens cell on my GT81 was dirty and having Badder wonder fluid and the correct clothes, I attempted a clean on both sides of the cell.

 

Doing everything correctly I find now I have an oily smear on the inside lens. Panicking I spoke to SC Telescopes who advised I hadn't damaged the coatings and that using the soft disposable J cloth type and breathing on the lens I should be able to remove the smears. I have tried this and it isn't working.

I would like to get it properly assess and  professionally cleaned as I've cocked it up and want the job done correct ( and hopefully I haven't damaged the objectives)  

Can anyone recommend a company that offer the service. If local to the midlands I can drop the lens cell over and collect, failing that all I'd need to do is send the cell by recorded delivery and well wrapped and insulated against travel damage. 

Thanks 

Allan

[parallaxerr]

Hi Allan,

I can sympathise, this happened to me once and I was stressed right out! But fear not...

In my case, the objective cell had some grease on the screw thread and I'd managed to transfer some to the back of the lens. Instead of wonder fluid, I then used some isopropanol alcohol and lens tissues to remove the smears, followed by breathing on the lens and wiping over with a microfibre cloth.

It sounds like you have something similar, it's amazing how far grease will spread on glass! Try the IPA and lots of lense tissues, a new one for each wipe. I'm sure it will work.

P.S. Lens coatings are a lot harder nowadays than some will have you believe. I clean my achro regularly without a care and it has never scratched. Residual marks are almost always smears!

[Alan White]

I have to agree, probably grease.
A little goes along way when you don't want it to.

[Allan the plumber]

8 minutes ago, parallaxerr said:

Hi Allan,

I can sympathise, this happened to me once and I was stressed right out! But fear not...

In my case, the objective cell had some grease on the screw thread and I'd managed to transfer some to the back of the lens. Instead of wonder fluid, I then used some isopropanol alcohol and lens tissues to remove the smears, followed by breathing on the lens and wiping over with a microfibre cloth.

It sounds like you have something similar, it's amazing how far grease will spread on glass! Try the IPA and lots of lense tissues, a new one for each wipe. I'm sure it will work.

P.S. Lens coatings are a lot harder nowadays than some will have you believe. I clean my achro regularly without a care and it has never scratched. Residual marks are almost always smears!

Thanks Jon

I really hope its grease! Can I ask where you got your IPA from make etc ( tried and tested) would like to use the same 

Thanks for putting mind at rest really thought I'd damaged the optics

[Doc]

Allan I bought a litre of IPA from Maplins a few years back to wash my mirror in my dob.

Not sure if they still sell it but I would imagine they do.

[Allan the plumber]

31 minutes ago, Doc said:

Allan I bought a litre of IPA from Maplins a few years back to wash my mirror in my dob.

Not sure if they still sell it but I would imagine they do.

Thanks Mike 

[parallaxerr]

52 minutes ago, Allan the plumber said:

Can I ask where you got your IPA from

I get mine from work unfortunately, but I hear you can get it at the Chemist too.

[Alien 13]

Maplin still do it, I got some recently 

https://www.maplin.co.uk/p/isopropyl-alcohol-1-litre-re71n

https://maplindownloads.s3-eu-west-1.amazonaws.com/RE71-9614.pdf 

I would say that IPA works best diluted with distilled water, now that stuff is as rare as hens teeth...

Another alternative is a lens pen a single wipe will remove any grease.

Alan

[ollypenrice]

The 'oily smear' effect is something you see when you look at your optics. It does not exist when you look through them. The idea is to look through them. That's why you have them. Chasing your tail to try to make optics perfect to look at is a beginner's mistake. 

Olly

[Allan the plumber]

2 hours ago, ollypenrice said:

The 'oily smear' effect is something you see when you look at your optics. It does not exist when you look through them. The idea is to look through them. That's why you have them. Chasing your tail to try to make optics perfect to look at is a beginner's mistake. 

Olly

Not too sure on that Olly I think I smeered the optics in my attempt to clean them looks worse than when I started ?

[ollypenrice]

14 minutes ago, Allan the plumber said:

Not too sure on that Olly I think I smeered the optics in my attempt to clean them looks worse than when I started ?

But do you mean the optics look worse when you look at them? How do they perform if you look through them? Imagine taking a nice refractor and painting a big black blob in the middle of the front lens. Then look at a Newtonian and what have you got? A big black primary mirror cell right in the middle of the objective. There is no magic in this. The Newt really does have a great big black spot - and spider vanes- right in the light path. Does it matter?

Olly

[Allan the plumber]

5 minutes ago, ollypenrice said:

But do you mean the optics look worse when you look at them? How do they perform if you look through them? Imagine taking a nice refractor and painting a big black blob in the middle of the front lens. Then look at a Newtonian and what have you got? A big black primary mirror cell right in the middle of the objective. There is no magic in this. The Newt really does have a great big black spot - and spider vanes- right in the light path. Does it matter?

Olly

Sorry Olly think I’ve not explained. I realise what your saying about Newts and the secondary.

when I attempted to clean the lens cell I’ve managed to smear something all over the lens and all the breathing on and using the lint free cloth I can’t get the smears off. It must effect the image as light will be scattered and will mess with the focus