Coronado Blocking Filter Rust Repair question

[aboy]

Hi there I have a rust blocking filter but, Stephen sent me the replacement for the filter I took off the rust filter and put in place the new one... visually looks excellent but, today I try to do a solar picture and turns out when I move the telescope to take another part of the sun the Image its totally white...

here some examples:







somebody knows what I did wrong?

[swisswalter]

Hi Herb

what scope/Setup. Is that a PST mod?

[aboy]

No. its a normal astrotelescope with 2 pre-meade solat filter and a BF15

[Merlin66]

Possibly needs a bit more tilt on the filter (remove some of ghosting)
I think the later images are, as you see, over exposed. Try some different settings. Moving the scope shouldn't have any affect on the filters - unless something is moving - diagonal/ camera?.....

[aboy]

Merlin that's my problem... When I move the scope to get another part of the image turns over exposed and if I try to adjusted I lost all the detail.

[Merlin66]

Hmmm
I have the same double SM60 stack/BF15 set-up on an ED80, and haven't found a similar problem...
What happens when you set-up on one edge of the solar disk and just let the image drift across the field of view...i.e. don't touch the scope, just turn the drive off.....do you get the same effect???
EDIT: What about a single stack arrangement - do you have the same problem??
Just trying to eliminate the possibilities......

[aboy]

Merlin here is my problem the en back of my blocking filter with the filter Stephen sent me now I can see a gap in the end of the BF is not 100% even. The original coronado doesn't looks like that before.

[marktownley]

Hi Herberth,

I had the same problem with a BF15 - but not with a BF10 - they must be 'different' blocking characteristics between the 2 Coronado models. Simple fix really, just use a nighttime Ha filter on the nose piece of the blocker unit.

It's an IR Leak you're getting.

The maier unit works in the Bf15 when used with a PST mod using a Baader D-ERF, however when I use the same bf15 with the SM90 external etalon I had the same problem as you. The SM series etalons use GG630 glass as the ERF and so pass light above 630nm, the Baader D-ERF uses the same RG630 schott substrate glass, but this has an additional UV/IR coating on it.

Hope this helps.

Mark

[marktownley]

Sorry to double post, but I bet a IR cut filter or UV/IR cut filter would work just as well as the 7nm nighttime Ha.

Mark

[aboy]

So, you think I have some light leaking some where in the filter?
Then I need to buy a h-alpha filter but what size I need ?

[marktownley]

The filter is functioning as per its spec, it's ultimately designed for use on the PST which, I believe, has an IR cut filter on its objective.

Any filter with an IR cut will work.

[aboy]

Ok. But when you talking about a PST I got confused because, my setup is not a PST.

Here my setup:

[marktownley]

Nice setup!

[aboy]

Thanks.
But where I need to put the filter? I'm going home right now I'll take a pictures of the filter and posting here

[marktownley]

Put the filter on the nose piece of the blocking filter.

[aboy]

Here is the BF:






Can you see the gap?

[marktownley]

can you see daylight around it when you hold it up?

[aboy]

Let me see and I'll let you know soon

[aboy]

Not at all.

[marktownley]

seems fine then