Cleaning a diagonal....

[Stu]

I've no idea how this happened as the diagonal is always stored with caps on, but I've just discovered this horrid mark on my Baader T2 BBHS diagonal. It looks almost a little sticky but have no idea what it is.

Any advice on safe cleaning will be appreciated, I won't touch it for now. These are obviously 1st surface but are they more resilient than a newt mirror for example?

Thanks!

[mark81]

Just had a look on a few other forums Stu and people suggest taking the mirror out altogether and giving a clean in the sink!?... Hmmmmm......

[newbie alert]

I cleaned mine with baader fluid and a camel cloth.

 

[Xplode]

I cleaned a diagonal a few weeks back.
I used a blower first, then a camel hair brush gently to remove kinda loose particles and last Kleenex+ Baader Wonder Fluid (the whole surface was covered) 
Diagonals often have better coating than mirrors, but not always, you can often find what kind of coating it has been googling the name of the diagonal.

 

Pretty bad before cleaning...

Very good after cleaning, a few particles left that i didn't remove. Cleaning them would probably hurt more than it would help.

I could only find a single scratch and it was there before i cleaned it.

Edited July 3, 2019 by Xplode

[Panda Alvin]

Looks somewhat like a slug trail... maybe a gastropod took advantage while you were out there, and wanted the front seat of the telescope ?  🙃
Ok... ill see myself out.

Edited July 3, 2019 by Panda Alvin

[Guest Vangelis]

If it's a dialectic coating just spray some Baader wonderfluid onto a Baader cloth ,use a blower brush first then a gentle wipe should remove it. As a further precaution to prevent nasties entering it always plug optic openings when outside with end caps. Once inside take them off when leaving accessories to dry out otherwise you will encourage mold formation.  I'm always careful when changing eyeoieces camera etc to plug the telescope openings quickly so that theres less opportunity for bugs etc to fly in.

[Rob]

Should be no problem Stu, panic not!.

I agree. Take the mirror out of the housing. Air dust with a bobble blower first, then run some distilled water over it to shift extra loose particulates. I then pop it in some warm water with just a touch of fairy liquid, keep your fingers to each side of the mirror run it around in the water for a while (don't run anything over mirror surface.. not even a wet microfiber cloth or fingers!.

Take out and swill it over with distilled water once again. The place a piece a kitchen towel out and prop the mirror up to dry.

Once fully dry. Finish with Baader Liquid & microfiber cloth. The re-assemble. All good!

Rob

[Stu]

Thanks all for the advise. I will.have a go over the weekend.

Any issues with maintaining alignment after removing the mirror?

[Rob]

54 minutes ago, Stu said:

Thanks all for the advise. I will.have a go over the weekend.

Any issues with maintaining alignment after removing the mirror?

I never come across anything Stu. Its frighteningly basic in side. usually a simple foam pad & v spring metal tensioner. Needless to say, clasp the diagonal in your hand with pressure on the back plate. Remove the 4 screws and un-tension the back plate slowly. You will soon see how on complex they are.

The v tensioner sits under foam/card in the middle to make sure the mirror is pressed fully upward to where it will then sit pressed fully square.. Its fine.

Best Rob

[Space Hopper]

One things for sure in this hobby......

Things never stay clean for very long ! 🙄

[Stu]

9 minutes ago, Tubby Bear said:

One things for sure in this hobby......

Things never stay clean for very long ! 🙄

Very true! I guess the good thing is that the kit is getting used!

[Rob]

Very true. I learnt not to fear along the way!... Also been lucky enough to meet (psychically & online) the right people to guide me.

Edited July 4, 2019 by Rob

[Rob]

Oh, needless to say some do have a rubber gasket, so keep An eye out for that too...

[StarryEyed]

Nothing wrong with astropoo!

Having to keep things clean from time to time means thay are cared for. Better to use it, clean it and wear it out than let it rot from lack of use. 

[ThomasLondon]

I recently used a swab for cleaning a dslr sensor and the respective fluid, worked great without removing the mirror.

 

Best 

Tom

[Rob]

How did you get on Stu?

[Stu]

33 minutes ago, Rob said:

How did you get on Stu?

Not had the peace and quiet to do it yet Rob! I checked out the housing and it has screws so looks easy enough to get apart. Thanks for the reminder, I will get on with it soon. Just been concentrating on my 8" f8 for the last week.

[Stu]

Well, that did not go so well in the end

What ever was on the surface was obviously not very kind to it. I ran it under a lukewarm tap, then let it soak in some slightly soapy water for a while. Didn't look like it was going to shift so I tried some Baader Fluid, and even without touching it at all it has developed some pinholes in the coating, pretty much trashed now

No idea is a replacement mirror is possible to purchase, otherwise it's a new diagonal unfortunately. Don't think I could have done anything differently really, didn't even touch it with a cloth or brush etc.

C'est la vie.

[Rob]

Oh man.. sorry to here this Stu. Wonder what the heck it was to do that much damage?!

[Rob]

Just a thought here... you could have a word with OO and have it re-aluminized?. 

[Stu]

14 minutes ago, Rob said:

Just a thought here... you could have a word with OO and have it re-aluminized?. 

That's a possibility I guess Rob. I have mailed Baader to see if I can get a replacement mirror. It was a BBHS diagonal so if I go OO then it loses what it had. Might at least maintain it as a decent quality diagonal rather than chucking it in the bin

No idea what it was on there, I'm thinking tree sap but how that got in there I've no idea!

[Stu]

I've had a nice reply from Baader, very quick I must say. They said they will have a look at it and give me their best price for a replacement. Good stuff.

[Stu]

Gosh, how time flies! I eventually posted this off to Baader, and confess that I took my time paying, so have only recently recieved this back. It cost just over €128, not insignificant but at least I now have my diagonal back in operation alongside the T2 Zeiss prism version. Nice to have it back in service.

[F15Rules]

Good to hear you have the diagonal back in service Stu. 

Did Baader give any indication as to what they thought the stain was caused by? It does make you wonder about the worth of such a high priced item versus something cheaper? I confess my much cheaper T2 prism (non Zeiss version) gives me superb views and I know that I could replace it for less than £100 if I had to..and I doubt that my much less than perfect eyes could see any difference between my diagonal and the Ultra high end units anyway😁.

Dave

[Carbon Brush]

Mirror damage was an an unexpected and expensive outcome.

Do you have any idea how long the stain/slime could have been on the mirror?

The reason for asking is that I have always assumed that 'average' bug splats, tree sap or whatever won't do harm if dealt with in a few days.

Asking the question while reaching for the stuff that hasn't been out this soggy and cloudy autumn....

David.