Lunt Blocking Filter Issues

[AstroJunk]

I can see this spoiling the end image. Fix or return? Are any others experiencing the same?

This is the scope side of a B600.

[h0ughy]

http://www.iceinspace.com.au/forum/showthread.php?t=91015&highlight=lunt+blocking+filter i had issues a few years back

[Star Catcher]

Hi Jonathon

I got a replacement and then proceeded to experiment with my fogged unit. I threw all sorts of things at it, including acetone and nothing shifted it. Until.......I struck the solution using a product called CLR from Bunnings. Gently unscrew the retaining ring. Careful not to slip off the recessed hole. once screwed off, soak for 30 seconds in CLR and then gently wipe with soft cloth or cotton pad moistened in CLR. Recommend you wear latex gloves. The filters will become as good as new in about a minute. There is no coating on the filter to destroy so no need to worry.

Pics for removal attached. And example of one bad unit that was cleaned to new.

Ted

[GUS.K]

Email Lunt, they will send you another blue glass filter.

[AstroJunk]

Massively helpful gentle peeps,

Many thanks! I'm heartened by the fact that the scope still performs outstandingly despite the issue. I wonder how many folk have never checked their blue filters and don't know that they can do even better.

[AstroJunk]

Legendary Ted!

Phone every Lunt owner and get them to check - Zero to Hero in under half an hour :bowdown:

[Star Catcher]

Yes it is a simple fix in the end. The only trick was to find what if anything would shift this crap. Once I had a replacement I could play lab experiments on the stuffed one :) I suspect most acids will work to a slower or faster effect and I think phosphoric acid is the ingredient in CLR. Come to think of it, I think Coke has a small amount of this acid as well :)

Ted

[AstroJunk]

I managed a very quick viewing of the sun this morning and all was very well visually. Can't wait to try it out with a camera at the weekend to see how much better it performs!

[tempestwizz]

While waiting for the replacement filter sent by Lunt to arrive, I tried the cleaning option mentioned by Star Catcher. It seemed to work quite well, so I didn't bother fitting the replacement when it arrived.
Now some 6 months after the episode I noticed the same fogging reappearing on the old filter. I note it was only where the filter was exposed to the ambient air, I.e. It was not evident around the edge that it was hel in by.
Others who have tried the cleaning option may care to review if they experience the same reappearance of fog.
Needless to say, I've replaced mine with the new one sent by Lunt, but I will still monitor the performance.

[Derek Klepp]

Brian they,ll eventually do the same I just recleaned mine in both my Lunt 100 and Lunt 60 good for another year or so.