This Mak corrector plate must surely be dirty enough to warrant a cleaning?

[ofranzen]

Hi all,

Tonight I got horrible dew buildup on the corrector plate on my SW MN190. No idea if the dew heater gave up or what happened. I know that one should clean as little as possible but I think pollen from earlier and tonight's heavy dew really made a nice cocktail on the plate. What do you say? Leave it or clean it? I have the Baader Wonder fluid, I think it's called, but can get something else if it's better suited. If this turns into a "remove the corrector plate situation", I will probably put it off for a while longer.

The photos exaggerate a bit I must confess, but it's quite a lot worse than a few years back.

Thanks in advance.

/Ola

 

[GalaxyGael]

Dust is no big deal, but organics can be problematic and there are either organics or inorganics within the dew that sedimented out after droplet dewetting. A gentle outside clean perhaps, not likely a lot of organic gunk got to the inside of the corrector. 

[Peter Drew]

Definitely in need of a clean, that degree of contamination will result in hazy images.  If the internal surface also requires cleaning remove the entire corrector cell and secondary assembly taking care not to disturb the orientation of the diagonal mirror.  It can only be refitted in one position as the diagonal must face the focuser, the collimation should remain intact.     🙂

[ofranzen]

I will definetely clean the front after tonight's session. The dirt is easily 95% on the front and very little on the inside. Doesn't look as bad in the dark though

 

[wimvb]

Gently clean the front only. You can use the wonder fluid. Or ”soften” the dirt with isopropanol first and the clean with wonderfluid. There’s no need to take the corrector off. But if you plan to do that in the future, make markings on it and the tube so you know how to put it back.

[ofranzen]

So I finally got around to cleaning the corrector plate. Followed this video's technique but I cleaned the corrector plate in place. 

Tried Baader's Wonder fluid after to get rid of some streaks and it got way worse. The distilled water gave the best result. Probably could have been even better with higher grade deionized water but I'm happy. This photo of the result was the "worst" I could get and the specs are either pits in the coating or on the inside. Some cotton fibres visible in the photo also got dislodged with some more air puffs. Very pleased.