Coronado BF 30 Fix

[solar]

Rust and more rust, appears to be an endless problem for a lot of people but not the manafactures.
Here is mine.


Here is what I did.
Firstly remove the filter retaining ring you see above. It can be unscrewed with two small screwdrivers.
Once removed turn it over and there is another retaining ring the same holding in the damaged filter. Unscrew this and the filter is free to go in the bin.
This next shot shows the two retaining rings, the Baader replacement filter and a machined silver ring 34mm and the centre machined to screw in the Baader 35nm filter.


Here we have the Baader filter screwed into the silver spacer ready to sit in the retaining ring it is sitting on. The second retaining is on the right and holds the assembly together.


Here it is ready for the second retainer ring.


This is the end result and when assembled gives the filter about 2Deg. tilt.


All back together.


My thanks goes the Ken Harrison (Merlin66) for his wealth of knowledge and advice.
Proof of life

[Merlin66]

John,
Yes....
The multicoated interference filter element is on the inside of a pair of glass plates and sealed around the edge.
If this edge seal breaks down for any reason (thermal stress, mechanical damage etc etc) then moisture gets into the coatings and they start to fail - from the outer edge and this "grows" inwards.....
I now keep my blocking filters in sealed Tupperware containers with lots of silica gel packs - I hope it will extend their life....

[solar]

Yeah John,
Even if you saw it starting I doubt there is anything you could do .
Here is the offending filter. Should have included it but forgot.

[swisswalter]

Looks like how my Astrodon UV filter went, although apparently it was a breakdown of the adhesive used in the sandwich. $300 worth of filter binned

Oh my god, I'm sorry for that

[swisswalter]

Hi John

that is a perfect venus shot