Solar imaging with a Baader UV/IR cut filter

[Mark at Beaufort]

On the weekend I attended the IAS festival and was interested in H.Alpha and White Light set ups.

I had a discussion with one particular stand owner about White Light Solar viewing and imaging using a Herschel Wedge. He advised me that I should use a Baader UV/IR cut filter in addition to my Baader Continuum filter because the final image would be much sharper.

I was not not convinced but decided to google to see what could be found on the topic. Well here it is - http://www.schursastrophotography.com/solar/Articles/solararticle3.html

The conclusion looks pretty impressive so has anyone tried this combination?  I have always been very satisfied with the view and imagine that I had taken through my 4" APO - Herschel Wedge + Continuum filter but for an additional £43 I am happy to experiment.

http://www.firstlightoptics.com/uv-ir-filters/baader-uvir-cut-filter.html

Any thoughts?

[keithatrochdale]

Hi

You might find this site useful for sun stuff;

http://solarchat.natca.net

[JB80]

This is another good page about using narrow band filters with the UV/IR.

http://dailysolar.weebly.com/white-light-imaging-with-narrowband-filters.html

I don't really use an UV/IR simply because I can't fit it in the train without using an adapter I don't have but I use an astronomik OIII clip filter.

I think it may vary a little too depending on what setup you have, can't say for certain but I imagine a wedge will be slightly different to a film filter and likewise different apertures and whether it's a frac or newt.

To ascertain for certain I will need to be sent a wide variety of telescopes, cameras, filters and accessories so I can gather as much data on all the potential variances.

Results to be posted...... eventually.

[Mark at Beaufort]

Thanks for the links. After I started this thread I remember I had a Baader Neodymium filter which has a UV/IR cut. If the Sun comes out I will try this filter to see if it makes any difference.

[michael.h.f.wilkinson]

Cutting IR makes a lot of sense when imaging. I have said Baader filter in 1.25" so will try it next time I do white-light imaging

[Mark at Beaufort]

I have a rather hazy Sun at the moment but it gives me an opportunity to see if I can gain focus using the Baader Neodymium filter as well as the Continuum filter. The binoviewers goes almost to the limit of the inward focus of the Astro Tech Frac - in fact I have just a centimeter left. Adding the Baader Neodymium filter into the train takes that limit almost to the buffers - about a millimeter left.

Although I can see the Sunspots the quality of the seeing does not allow a comparison to be made. Hopefully, the Sun will shine tomorrow or Friday to do both a visual and imaging test.

[Merlin66]

The addition of a UV-IR cut is usually considered for imaging (not visual) were there may be a leak of IR to the camera....

Bear in mind that the response curve of the usual CCD camera "flat lines" around 1000/1100nm, and doesn't record into the NIR etc.

[Mark at Beaufort]

Thank you Ken I was hoping you might reply. So I won't bother with the visual but I will take a few comparison photos using different set ups to see if I get any difference with my Canon DSLR.

[David Smith]

Has your DSLR been modified to remove the original filter? If not then this will include UV/IR filtration, or so I believe. The article in your link was relating to the use of a DMK 31 or 51 which will not have any filtration as standard.

[Mark at Beaufort]

Thanks David. No my Canon has not been modified so it has the UV/IR filtration. Clearly I am still in the learning stage of astro photography.

[Luke]

So hopefully you don't need a UV/IR cut, then, Mark, if your camera cuts it anyway?

I get a fuzzy image when capturing if I don't use a UV/IR cut with my Tele Vue 85, Lunt 1.25 wedge and Solar Continuum. Whereas I don't need to use a UV/IR cut with my Equinox 120, Baader wedge and Solar Contiuum, the image is great on screen without one. As far as I know, that's because the scope's Schott glass element cuts IR

I ran into this when trying to image with my Celeston Onyx 80mm. I got disappointing results, which puzzled me because views through the eyepiece were very good. It was the IR leak

[D4N]

I'm a little confused by this, I image the sun using a Baader solar continuum filter and an ASI120MM without an IR/UV cut filter just the Baader solar film.

I get plenty of granulation and detail, certainly a lot more than seen on that first link.

I'm not aware that my scope has any IR cut in it, wouldn't that likely effect Ha transmission?

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[Luke]

Is this with your refractor, Dan? I think how much the UV/IR cut helps depends on your refractor. H-a won't be affected, as that's within the visible spectrum.

I'm a little confused by this, I image the sun using a Baader solar continuum filter and an ASI120MM without an IR/UV cut filter just the Baader solar film.
I get plenty of granulation and detail, certainly a lot more than seen on that first link.
I'm not aware that my scope has any IR cut in it, wouldn't that likely effect Ha transmission?


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[D4N]

Yes, is it normal to have IR cut built into an APO?

I have a TSED70Q.

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[Luke]

Yes, is it normal to have IR cut built into an APO?

I have a TSED70Q.

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I don't think the Schott glass of my Equinox is there to cut IR, it just happens to (as far as I know) naturally cut it. My Tele Vue 85 is a doublet so I would imagine has far more limited colour correction than a good quadruplet, but that's just my vague guess    My Onyx is also a doublet, and suffers badly with IR. My Equinox is a doublet too, but has Schott glass. Hopefully someone who knows far more about refractor optics can chip in?

What is clear, is that some refractors work better without the UV/IR cut than others. I'd love to know why that is!

[teleskopjo]

If you have the Astronomik L filter from the Type2c LRGB set it should work too as an IR blocker

[Steve Ward]

I wouldn't be without the Baader UV/IR Block in the mix alongside the Continuum for close-ups with the Mono SPC900NC , the Continuum bleeds IR and the difference is marked between with and without.

For my DSLR shots I use an OIII with the Baader ND3.8 with no extra IR block as the built-in filter on the 1000D does the job and experimenting with an extra UV/IR Block made no difference.