"rusty" coronado blocking filter

[Atacamallama]

I have a second hand Coronado Maxscope and have noticed, too late, that the blocking filter is discoloured. It is as if there is a clear patch in the centre. It still seems useable (e.g. Stargazers Lounge - Atacamallama's Album: Album - Picture) but I fear the worst... It's fairly certain I have no guarantee claims, so what can I do? can these be bought new? It occurs to me to pick up a cheap PST and canibalise the blocking filter from it...My understanding is that it would be a nightmare to get help from the manufacturers....

[russ]

It's a nightmare. I bought a secondhand PST and didn't notice until too late that the main objective was 'rusty'. Telescope House have quoted £150 to repair. Was going to get a secondhand objective but Telescope House have told me you can't just change the objective.

Looks like you are still getting good results from the Maxscope and if safety isn't an issue, perhaps you could soldier on?

[Atacamallama]

thanks for that, I shall keep soldiering on, indeed. I am also wondering if I could use a different BF anyway, say, BF10 instead of the BF5 (which is what I assume this is) which begs the question where I could source one...

[John]

The Cloudynights forum keep a register of PST's affected by this and have quite a lot of information on this topic:

Telescope Reviews: Viewing forum: Solar

It is a real issue though and not one with an easy solution I fear. Blocking filters are not cheap !.

[Atacamallama]

thanks for that, just a reminder this is not a PST and the problem is the BF, not the objective...

[John]

thanks for that, just a reminder this is not a PST and the problem is the BF, not the objective...

Sorry I should have spotted that

Still potentially a rather nasty issue I would think

[Atacamallama]

so it possible to source BF filters seperately in the UK? I notice they seem to come in different sizes, bigger ones being better for imaging, apparently...

[dmahon]

You can get the filters seperately, however they appear to be designed to work with a specific etalon if the description is correct (but I don't really understand solar scopes).

=6"]Lunt Optical Accessories

[David Galvin]

I would strongly recommend the wise words of Merlin 66 on this forum.

Stargazers Lounge - View Profile: Merlin66

[Merlin66]

I've just replied to Atacamallama....

The Blocking filter has started to fail....unfortunately not an uncommon occurance.....

Getting suitable replacements is getting more and more difficult/ expensive.

[David Galvin]

I've just replied to Atacamallama....

The Blocking filter has started to fail....unfortunately not an uncommon occurance.....

Getting suitable replacements is getting more and more difficult/ expensive.

As always, trusted advice