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New Lunt Solar Systems Modular Telescope line up

solar refractor imaging
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35 replies to this topic

#26 nicknacknock

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Posted 07 July 2020 - 07:45 AM

Hi Faye,

 

One clarification please: The original question was about viewing in Ha. Given the pure monochromatic views in Ha band of a single wavelength of 656nm and change, using ED doublet configuration does not seem to provide an inherent advantage / any benefit purely for the Ha bit of the new scopes. Please comment on that.

And still waiting for a response to this...



#27 nfotis

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Posted 07 July 2020 - 10:30 AM

And still waiting for a response to this...

It's my impression that the idea behind using a high quality scope is to not compromise quality for non H-a users, so you could enjoy the scope also as a visual one. Personally, I feel that I would prefer to have a separate dedicated scope for white light/CaK use instead of disassembling the Lunt Ha set every time.

 

N.F.



#28 nicknacknock

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Posted 08 July 2020 - 12:10 AM

Same here. Separate scope for each intended use. But it is a more expensive proposition to have 3 scopes, one for visual, one for CaK and one for Ha, so there is merit I guess to the idea.



#29 nfotis

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Posted 08 July 2020 - 05:58 AM

Well, it depends on your arsenal. I don't own a refractor (yet), but I could see getting eg a Skywatcher Evostar 120 for use with the CaK module, as the latter's cost dwarfs the scope (and I could use the Baader Astrosolar film for my existing Skymax 127).

 

N.F.


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#30 nicknacknock

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Posted 08 July 2020 - 06:01 AM

Re CaK module, a simple achro does the job just fine as it is single narrowband imaging.



#31 LuntSolar

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Posted 30 July 2020 - 03:55 PM

The new Day and Night MT series are designed to be used through a wide range of wavelengths. CaK, H-alpha, and White Light (which would cover night sky and terrestrial observing). If your only interest is H-alpha then the upgrade to the new objective might not provide any noticeable improvement.

 

However, if your interest is in a system that is optimal for a broad spectrum then you would see significant improvement when using the scope for CaK and White Light. In fact, the singlet design of the previous 60T would not provide a good image of the Sun in White Light at all. 

 

The singlet lens system works for a monochromatic beam to be sharply imaged at the image plane. However, we need to introduce an Etalon into the light path. This requires that we collimate the light path through the etalon and then re-focus. This required that the collimation lens also do some minor correcting of the singlet. However, the collimating lens could not do a full 100% of both jobs.

 

By upgrading the objective to a higher quality doublet we removed the issue of broadband correction (vs dedicated) and also slightly improved the collimation through the etalon. This "theoretically" should improve the performance of the etalon over a wider FOV. Whether or not this improvement will be noticeable in the field is yet to be determined. But it certainly won't hurt the H-alpha views.

 

Our larger models have very high quality objectives, including a triplet. These upgrades were done such that the user would have the best of ALL worlds.

The 152T is the closest thing we have/had to a Modular Day and Night scope. The 152T could be used for H-alpha, CaK, and Night. The 152mm OTA is fairly well known. It was a great performer at 656nm, a "fair" performer at CaK, and "okay" at Night viewing. The 130mm, (triplet APO) while being smaller, is a huge improvement over the 152mm. The 130mm has proven to be an excellent performer that meets the expectations of critical users across the entire range of applications.

 

If H-alpha is your only interest, then a dedicated Lunt system is certainly a great choice. There are certainly some cost savings to getting a dedicated system. But it should be worth noting that a Modular system is a plug and play system and can be upgraded later with additional modules as your interests change. ie: a CaK module or a White Light Wedge. The Modules systems are easily converted to a Night System.


Edited by LuntSolar, 30 July 2020 - 03:56 PM.

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#32 nicknacknock

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Posted 30 July 2020 - 11:50 PM

Quick question on CaK module: I've heard that it performs best at f10 and slower. Does that apply?



#33 LuntSolar

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Posted 31 July 2020 - 05:15 PM

The Lunt CaK modules work well on all f7 refractors (or longer). I think the issue of longer focal length arises from some of the first designs of the CaK module.

Initially the Induced Transmission Filters of the CaK module were small in diameter (the technology for larger CA filters did not come about for several years). They are highly reflective filters that needed to be tilted at 1-1.5 degrees and spaced about 2-3" apart to prevent ghosting.

The first ITF was placed in the opening of the 2" draw tube/nose of the module (diagonal or straight through). The second was placed about 2" down the same tube and also well spaced from the blocking filter.

We recommended that the user match the BF to the focal length of their scope. In cases such as the 18mm blocking filter we recommended that the user have a fairly long focal length to take advantage of the increased size of the BF. The first ITF was placed quite a distance up stream in the light path and would act as a very restrictive aperture stop otherwise. Thus, not allowing the user to take advantage of the 18mm BF.

This issue was not a problem for the smaller systems.

 

The Lunt CaK modules have full aperture ITFs and are well suited to the new Day and Night MT series of telescopes.


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#34 nfotis

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Posted 31 July 2020 - 06:32 PM

This reminds me, what's the maximum size camera sensors we can use with the various blocking filters?

It's not very clear on the site (eg, APS or 4/3 sensors can work? or we do need to plan for smaller sensors like the ASI533 or ASI183?). At the moment, I have only Canon DSLR cameras (both full frame and APS)

N.F.

#35 ron scarboro

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Posted 25 August 2020 - 09:58 PM

I’d like to buy off Amazon as I can utilize my AMEX points.  However, it seems all the Amazon packages are for the BF12.  Is there an Amazon option for the BF18 that I’m missing?  Is there a way to buy that then swap for the up charge with you?

 

Thanks,

 

Ron



#36 chemman

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Posted 04 October 2020 - 12:23 AM

So last night setup my  LS100MT-DS for night viewing.   Took off the double stack and put on the 2" rack and pinion, backed by a JMI electronic focuser.  Captured about 350 frames with a LPI-G and 6.3 focal reducer, best 250 images.  

 

1QTQc4H.jpg


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