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Lunt H-alpha filters


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After reading a few threads about Lunt H-alpha telescopes here on SGL, I did a bit of research for curiosity about Lunt options.

Can someone explain me what is the advantage in getting (1) a front Lunt 60mm Ha Etalon Filter + B1200 Block 2" 

(http://astrograph.net/epages/www_astrograph_net.sf/en_GB/?ObjectPath=/Shops/www_astrograph_net/Products/"AG0LS60FHa2/B12"

compared to (2) a dedicated solar scope Lunt 60mm + B1200 block? 

Also, I can see that (1) can be used with different telescopes, but the frontal aperture of the filter is 60mm so differences between telescopes of different apertures will be on magnification (unless I miss something...:icon_scratch:). 

 

Piero

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The 60mm front etalon is just that,a 60mm aperture etalon compared to the 35mm etalon in the 60mm solar telescope. Etalon costs rise dramatically with aperture. Sweet spot size is related to etalon aperture and stand alone sets permit fitting to a better telescope than the stock one.  :icon_biggrin:

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So, if having a front etalon is better, a owner of a ~90-100mm refractor could get something like a Coronado SolarMax II 90mm filter set with rich view tuning and 15mm blocking filter for about the same money of a Lunt 60mm Pressing Tune and FT..  

https://optcorp.com/products/coronado-solarmax-ii-90-h-alpha-filter-w-bf15 )

Any downside?  :D 

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I shall follow this with interest - ‘cos I certainly can’t explain/understand any ‘advantage’.

As you write, it could be used with different scopes but one would need the different adapters necessary for each scope and I can’t see what the upside would be, if there is any.

(I’d repeat your scratching the head emoticon/smiley thingie if I could find it. ?)

EDIT: oops, late in again.

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No, no down side.

Both the Lunt and Coronado external etalons have tilt tuning and similar technical performance. The Coronado design includes the "Richview" fine tuning ( I personally don't like it, but many others seem to get it to work for them)

The 15mm blocking filter would be good for focal lengths up to around 1500mm.

 

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Decisions, decisions.....

I use my SM60/ BF15 etalon on the ED80...

The TS102 (f11) is used in a dual white light (Herschel wedge) and Stage 2 PST mod...

I also have added an Omega CaK filter stack to the TS102 with some success.

You don't need to use the top of the range scopes for Ha - monochromatic light. The Strehl ratio at Ha wavelength is what's it all about. In basic refractors this usually comes down to the Spherical aberration corrections (if any)

 

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1 minute ago, Merlin66 said:

You don't need to use the top of the range scopes for Ha - monochromatic light. The Strehl ratio at Ha wavelength is what's it all about. In basic refractors this usually comes down to the Spherical aberration corrections (if any)

I see your point and agree. 90mm aperture is a big step compared to 60mm though!  

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The improvement is in the surface  detail/ proms resolution, not in the bandwidth being used. The choice usually comes down to a small aperture with a double stack (better contrast and Ha detail) v's a larger aperture single stack.....

Decisions, decisions.....

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Difficult question.....

Yes, the overall contrast and definition (Ha) with the double stack is great. - whatever the aperture.

It depends on what you really want to do....

A SS larger aperture will give bright views large solar disk coverage and lots of detail; To get some of the benefits of the DS - high Ha contrast but with narrower field (photographically) is the core marketing for the Daystar Quark(s). May be a combination should be considered???

 

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For me, I found that a 50mm or 60mm front mounted etalon just wouldn't screw on to the front of my 15" dob!! :grin:

So, I went for a dedicated solar scope - 50mm Lunt with ERF & BF600 with pressure tuning included.  I guess the internal nature of the etalon allows the size and hence cost to be reduced: a 50mm aperture setup can be acquired for much less than the cost of fitting out a frac, especially when you don't have one to start with!!

As you already have a frac, I think you are right: there are several options available to you that could bring advantages!

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5 hours ago, niallk said:

For me, I found that a 50mm or 60mm front mounted etalon just wouldn't screw on to the front of my 15" dob!! :grin:

So, I went for a dedicated solar scope - 50mm Lunt with ERF & BF600 with pressure tuning included.  I guess the internal nature of the etalon allows the size and hence cost to be reduced: a 50mm aperture setup can be acquired for much less than the cost of fitting out a frac, especially when you don't have one to start with!!

I can't imagine a 15" h-alpha! :D 

I think you are right about cost reduction, and that could be the reason why the smaller etalon in the Quark reduces the cost even further.

 

Ideally, I'd go for a quark as it can be fitted on the TV60 or Tak100. QoC concerns are too high though, especially because it doesn't seem clear how issues can be avoided completely. If I were told that mounting a front ERF filter theoretically enables the quark to work for a lifetime or so, I would get the Quark and ERF as soon as I can. However, I have also read reports where the electronic components of the Quark failed, so it seems to me that more research and quality control are needed. 

Between getting a dedicated telescope and a filter set + blocking filter, I'd get the latter, having already two refractors to play with.

As Merlin said, decisions decisions....

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I think you would need to buy the 90mm Coronado etalon and BF15 set at the $US price to make the financial comparison. I have a 90mm/B15 set and the image brightness and details are better than smaller versions. However, it's not a patch on my 150mm PST mod with a 20mm internal etalon.  :icon_biggrin:

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46 minutes ago, Piero said:

Given the large sum of money for these toys, warranty and customer service should also be considered.. 

Regarding these, Lunt seems to win hands down. 

Just as an anecdote, not an across the board judgement, I found Lunt’s response to my queries was exemplary. Definitely displayed a ‘we are here to help’ attitude - which is very refreshing. ?

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I suspect a 90mm ha filter mated to your Tak would be spectacular Piero - as Garry's posts on his Tak/75mm external Lunt filter set up suggest.

It's a different proposition to a smaller dedicated double stacked scope which should produce more detailed, though less bright and magnified surface views. 

Of course if you go for one external 90mm filter, there's always the option of adding a second one later if you find some spare change down the back of a sofa.

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3 hours ago, Highburymark said:

Of course if you go for one external 90mm filter, there's always the option of adding a second one later if you find some spare change down the back of a sofa.

Mods! This outrageous encouragement to profligation must be discouraged for the sake of us all ... ??

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