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Help, what's wrong with my Lunt BF

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#1 MAURITS

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Posted 21 April 2018 - 08:42 AM

I looked to the sun yesterday and the view was not so clear as usually.

 

Than I saw a matte stain to the telescope side of the Lunt B1800 BF ....

 

This is not a normal thing, so what's wrong with the BF.

 

Note: at the end of past summer I still looked to the Sun and the view's  where clear , then was everything still fine, until now.  frown.gif

 

Thanks! 

 

 

DSCN5374 klein.jpg


Edited by MAURITS, 21 April 2018 - 08:47 AM.

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#2 CHASLX200

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Posted 21 April 2018 - 09:15 AM

Looks like it is fogged up. Maybe under warranty still.  Get a hold of Lunt.



#3 bob71741

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Posted 21 April 2018 - 09:22 AM

MAURITS - It's a common problem, but easily fixed; you can try cleaning the filter yourself, or request a new one from Lunt.

 

There are several posts about cleaning on this CN forum. I did not use the acrylic cleaner mentioned on a couple of posts, but got good results with a lens cleaner.



#4 MAURITS

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Posted 21 April 2018 - 10:05 AM

bob71741, are here on CN examples how I can clean (fix) this problem, I can't find them ...



#5 vincentv

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Posted 21 April 2018 - 11:27 AM

Maurits,

What follows can be found in other posts, but to summarize:

-Lunt has confirmed that is a glass filter of Schott's BG family. It has no coatings and can be safely polished.

-I have used meguiar's plastx with good results. Someone else recommended it in another thread.

-The glass is sensitive to humidity, lunt's version of the rusted ITF.

-There is no danger

-Lunt can send you a replacement. They didn't charge me but I'm within the warranty period.

 

Regards



#6 BYoesle

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Posted 21 April 2018 - 04:03 PM

Remember humidity is not your friend with any of the blocking filters.

 

The current Lunt blocking filters filter do not use an ITF as used in earlier Lunt BF's and the Coronado BF's - it is a relatively simple uncoated soda-lime glass colored filter.

 

Lunt will replace the BG ("blue glass") filter even out of warranty or for secondary owners. You can try also try to remove the film yourself:

 

http://www.iceinspac...ad.php?t=144429

 

https://www.cloudyni...ki#entry5592771



#7 MAURITS

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Posted 22 April 2018 - 06:22 AM

I cleaned the filter glass and most of the dirt is gone.

 

There is a small amount that I can not remove but I saw in the above link a cleaning product that's seemingly amazing. (Meguiar's PlastiX).

 

I don't know if this is for sale in Belgium, maybe similar replacement, I dont know...

 

A big thanks to all the people who answer me waytogo.gif

 

DSCN5376 klein.jpg

 

PS

 

The views are "almost" so clear as a new one but a little bit fuzzier.


Edited by MAURITS, 22 April 2018 - 06:26 AM.

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#8 MAURITS

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Posted 22 April 2018 - 08:14 AM

Meguiar's PlastiX is available in Belgium and is in order wink.gif

 

I will give an update if I have used.



#9 MAURITS

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Posted 25 April 2018 - 03:44 AM

I have meanwhile received the cleaning product "Meguiar's PlastiX".

 

The result is indeed amazing, the blue glass is like new and the views were clear and crisp  smile.gif

 

So thanks again for the advice  waytogo.gif



#10 highfnum

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Posted 26 April 2018 - 04:59 PM

i had similar problem

i took a photo emailed to lunt

they sent new filter and instructions

 

in my case not clean able

etched in glass 



#11 Live_Steam_Mad

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Posted 26 April 2018 - 06:04 PM

That blue glass part is not the actual "Blocking Filter" that removes the harmonics of the Etalon, instead the "Blocking Filter" is underneath where your eyepiece goes. Just FYI.

 

Lunt will replace the blue glass part even out of warranty so I read.

 

Unlike our local club's PST whose ITF filter is 90 per cent rusted and needs replacing, which we are currently doing. And we have to pay for a replacement filter ourselves...

 

Regards,

AG



#12 highfnum

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Posted 26 April 2018 - 10:01 PM

above is correct



#13 MAURITS

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Posted 27 April 2018 - 03:50 AM

I have the original BF cleaned and I recieved a extra new free blue glass from Lunt (the BF was out of warranty period).  waytogo.gif

 

A big thanks to Lunt for the great service.  wink.gif


Edited by MAURITS, 27 April 2018 - 03:53 AM.

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