Cleaning smears on maksutov corrector plate

[bendiddley]

I have just cleaned my maksutov corrector plate, but there are still smears on the glass and I don't know how to get rid of them. I have tried using baader wonder fluid, ROR residual oil remover with a clean baader wonder cloth and clean micro cloths, I have tried 'haaa-ing' on the glass too, but nothing is shifting them, I think they might now be permanently there. Can anyone help and tell me if it is possible to get rid of them? Thanks.

[LukeSkywatcher]

Got a pic?. They wont make any difference to the views.

[bendiddley]

It's very hard to see them in the photo, but you can just about make them out.

[johninderby]

As mentioned unlikely to be noticeable when observing.

You might find this usefull

http://arksky.org/asoclean.htm

[LukeSkywatcher]

4 minutes ago, bendiddley said:

It's very hard to see them in the photo, but you can just about make them out.

Are you sure they are definitely on the outside of the corrector?. Nothing there to worry about. 

[bendiddley]

5 minutes ago, johninderby said:

As mentioned unlikely to be noticeable when observing.

You might find this usefull

http://arksky.org/asoclean.htm

Thanks that's an interesting article, lots of good advice, not sure I feel confident at mixing up his concoction though, but everything is very useful.

[bendiddley]

3 minutes ago, LukeSkywatcher said:

Are you sure they are definitely on the outside of the corrector?. Nothing there to worry about. 

Yes, but it looks like they are on the inside as well.

[Oddsocks]

The marks on the inside of the corrector are most likely vapour deposits left by volatiles that evaporate from the grease on the moving mirror support or the paint and glues used for internal flocking. It is common with enclosed OTA’s such as SCT’s and Mak’s that are stored indoors in warm conditions or are used in the daytime for solar observing.

The few marks visible on the outside look like acid etch spots left by pollen, I can’t see any external streaky marks in the image but maybe they are too faint to show.

The corrector is multicoated to reduce reflections and improve light transmission, if the coating is carried out poorly this can also leave the corrector with ‘streaky’ looking marks.

In use, vapour marks have little impact on the views for most objects though very bright objects such as the moon may show a little reduction in contrast.

Vapour deposits left behind by volatiles are very tenacious and difficult to remove without solvents once dried and unless you know the chemical make up of the deposit many solvents won’t work while some solvents may damage the optical coating.

To clean the inside of the corrector would need it to be removed from the OTA and the rotational relationship between the corrector, primary and secondary mirrors are tuned in the factory to minimize aberration so if you did remove the corrector for cleaning you would need to mark it’s position relative to the tube and other optical components and ensure it went back with exactly the same orientation.

If you can see vapour deposits on the corrector glass they will almost certainly be on the secondary and primary mirror too so once you begin a cleaning task like this you may end up having to clean all the components as you chase the contaminants around the optical surfaces.

If you are determined to attempt a clean of the optical surfaces then a long soak of many hours in a bath of warm water and detergent followed by a clean using isopropanol alcohol, following general guidlines for cleaning newtonian reflectors, should remove any volatile grease deposits however if the deposits are from paint or glue volatiles it is unlikely this treatment would have much effect.

HTH.

 

[bendiddley]

Wow, odd socks you have come to my rescue once again! Really appreciate your time writing that for me, thank you. Not sure what my course of action is right now, I may just leave it alone, but I think I have enough know-how to attempt a clean if I want to. Cheers.

[BGazing]

Try saliva for resolving organics, or acetone. Be careful with acetone and plastics. Always finish with isopropyl and distilled water...

What you show is nothing to worry about...and i baby the heck out of my optics.

[LukeSkywatcher]

21 minutes ago, BGazing said:

Try saliva for resolving organics, or acetone. Be careful with acetone and plastics. Always finish with isopropyl and distilled water...

What you show is nothing to worry about...and i baby the heck out of my optics.

Saliva?. Are you sure about that?. Its full of organics that will fester and grow on the plate.

Dont lick your plate.

(pun intended)

[HunterHarling]

Kleenex and windex is the only thing that has worked on smears for me. Use a new kleenex for every wipe.

Works great.