Lunt Cak b1800 straight through module

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Lunt Cak b1800 straight through module

Post by Stardust5858 »

Hi all, I've just placed an order for a Lunt CA-K straight through module which will be used on my 80ed. I'm a little concerned about longevity of the filters long term.
Can these filters be used with a hershal wedge with no ND filters installed?

Have others got or have used this filter in the past/present?

Any guidance on usage would be great, there doesn't seem to be much information out on the world wide webby thing.

It'll probably be week's or months before it arrives as it wasn't in stock, lol. Just wanted some heads up.

Thanks

Nigella


10ft x 6ft Solar RoR with Warm Room
Lunt 60mm Double Stack HA
80ed WL+ Lunt Hershal Wedge + Badder K-Line filter.
100mm AR + Lunt b1800 Ca-K module.
Neq6 Eq Mount.

2.7m Pulsar Dome.
11in Celestron SCT + White Light Filter.
70mm AR Stellavue.
12inch OO Newtonian.
Nec6 Eq Mount.
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Re: Lunt Cak b1800 straight through module

Post by EGRAY_OBSERVATORY »

Hi Nigella,
Assumingly you are referring to one of these shown as https://redcarpettelescopes.com/product ... m-k-module ??
If so, I have the Lunt B1200 CaK module for 10-years and with the Lunt 60mm scope, have never had any problems at all.

I don't quite understand why a Hershel Wedge would be involved in that scenario though. I would image that an F-stop over the objective, might be required, but definitely I am not in a position to confirm that, whereas Mark T., might be able to advise better...

Best wishes
Terry


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Re: Lunt Cak b1800 straight through module

Post by Stardust5858 »

EGRAY_OBSERVATORY wrote: Sat Mar 13, 2021 11:27 pm Hi Nigella,
Assumingly you are referring to one of these shown as https://redcarpettelescopes.com/product ... m-k-module ??
If so, I have the Lunt B1200 CaK module for 10-years and with the Lunt 60mm scope, have never had any problems at all.

I don't quite understand why a Hershel Wedge would be involved in that scenario though. I would image that an F-stop over the objective, might be required, but definitely I am not in a position to confirm that, whereas Mark T., might be able to advise better...

Best wishes
Terry
Thanks Terry, yes those are the one's. It'll probably out live me then, lol. I was just wondering about filter failure. Probably I'm just being paranoid about sticking something in the light path at the end of the telescope, lol.


10ft x 6ft Solar RoR with Warm Room
Lunt 60mm Double Stack HA
80ed WL+ Lunt Hershal Wedge + Badder K-Line filter.
100mm AR + Lunt b1800 Ca-K module.
Neq6 Eq Mount.

2.7m Pulsar Dome.
11in Celestron SCT + White Light Filter.
70mm AR Stellavue.
12inch OO Newtonian.
Nec6 Eq Mount.
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Re: Lunt Cak b1800 straight through module

Post by EGRAY_OBSERVATORY »

Indeed Nigella, I am certain as Lunt have been around for a long time now and since the previous connection with another firm, has (to the best of my knowledge) ever had any problems with their products, as long as obviously they are treated properly and safely too.

Personally I believe that due to the nature of Solar-viewing through any form of instrument, that these manufacturers have to be ultra-careful to make sure their components etc., are safe enough that no expensive-recriminations occur against themselves, as long as those components are used within the manufacturers own safety-standards.

Please do check with say Mark T., for any other advice for your requirements.

Cheers
Terry


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Re: Lunt Cak b1800 straight through module

Post by marktownley »

Hi Nigella,

The Lunt CaK modules are stated fine for up to 100mm aperture. If you use a wedge there won't be enough light.

Mark


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Re: Lunt Cak b1800 straight through module

Post by krakatoa1883 »

Hi Nigella

Yes, it is possible to use the CaK filter of the Lunt module without the BF barrel into the Herschel wedge (with no ND filters inside). You have to unscrew the long BF barrel, convert the male T thread into a female one and put a 1.25"/T nose on this. As a narrowing BF is however still necessary you can make use of your Baader K filter, the result of the mode should appear this way
LuntmodK.jpg
LuntmodK.jpg (33.51 KiB) Viewed 319 times
As the wedge passes only 4-5% of the light there will be probably not enough of it for hires imaging, however for full discs and medium res it works fine as in the example below
1 wedge as.jpg
1 wedge as.jpg (86.19 KiB) Viewed 319 times
Others made a similar mod with a CaK PST filter + Herschel, there should be a couple of discussions in this same forum.


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Re: Lunt Cak b1800 straight through module

Post by Stardust5858 »

EGRAY_OBSERVATORY wrote: Sat Mar 13, 2021 11:52 pm Indeed Nigella, I am certain as Lunt have been around for a long time now and since the previous connection with another firm, has (to the best of my knowledge) ever had any problems with their products, as long as obviously they are treated properly and safely too.

Personally I believe that due to the nature of Solar-viewing through any form of instrument, that these manufacturers have to be ultra-careful to make sure their components etc., are safe enough that no expensive-recriminations occur against themselves, as long as those components are used within the manufacturers own safety-standards.

Please do check with say Mark T., for any other advice for your requirements.

Cheers
Terry
Thanks Terry, appreciated.


10ft x 6ft Solar RoR with Warm Room
Lunt 60mm Double Stack HA
80ed WL+ Lunt Hershal Wedge + Badder K-Line filter.
100mm AR + Lunt b1800 Ca-K module.
Neq6 Eq Mount.

2.7m Pulsar Dome.
11in Celestron SCT + White Light Filter.
70mm AR Stellavue.
12inch OO Newtonian.
Nec6 Eq Mount.
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Re: Lunt Cak b1800 straight through module

Post by Stardust5858 »

marktownley wrote: Sun Mar 14, 2021 7:04 am Hi Nigella,

The Lunt CaK modules are stated fine for up to 100mm aperture. If you use a wedge there won't be enough light.

Mark
Thanks Mark, appreciated. I'll use as is straight out the box then, lol.


10ft x 6ft Solar RoR with Warm Room
Lunt 60mm Double Stack HA
80ed WL+ Lunt Hershal Wedge + Badder K-Line filter.
100mm AR + Lunt b1800 Ca-K module.
Neq6 Eq Mount.

2.7m Pulsar Dome.
11in Celestron SCT + White Light Filter.
70mm AR Stellavue.
12inch OO Newtonian.
Nec6 Eq Mount.
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Re: Lunt Cak b1800 straight through module

Post by Stardust5858 »

krakatoa1883 wrote: Sun Mar 14, 2021 8:37 am Hi Nigella

Yes, it is possible to use the CaK filter of the Lunt module without the BF barrel into the Herschel wedge (with no ND filters inside). You have to unscrew the long BF barrel, convert the male T thread into a female one and put a 1.25"/T nose on this. As a narrowing BF is however still necessary you can make use of your Baader K filter, the result of the mode should appear this way
LuntmodK.jpg

As the wedge passes only 4-5% of the light there will be probably not enough of it for hires imaging, however for full discs and medium res it works fine as in the example below
1 wedge as.jpg

Others made a similar mod with a CaK PST filter + Herschel, there should be a couple of discussions in this same forum.
Thanks Raf, appreciated. I'll probably use as but will probably experiment when I've used it for a while.


10ft x 6ft Solar RoR with Warm Room
Lunt 60mm Double Stack HA
80ed WL+ Lunt Hershal Wedge + Badder K-Line filter.
100mm AR + Lunt b1800 Ca-K module.
Neq6 Eq Mount.

2.7m Pulsar Dome.
11in Celestron SCT + White Light Filter.
70mm AR Stellavue.
12inch OO Newtonian.
Nec6 Eq Mount.
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Re: Lunt Cak b1800 straight through module

Post by Carbon60 »

Hi Nigella,

I use the Lunt B1800 CaK straight module on a Tecnosky 125 without any issues. No mods, 'just as is' works fine.

I do add a 'finessing' filter with a narrower bandpass to bring up some additional details, but this is not necessary to make the module work on the scope. That's more about tweaking...... as we do.

Stu.


H-alpha, WL and Ca II K imaging kit for various image scales.
Fluxgate Magnetometers (1s and 150s Cadence).
Radio meteor detector.
More images at http://www.flickr.com/photos/solarcarbon60/
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Re: Lunt Cak b1800 straight through module

Post by EGRAY_OBSERVATORY »

Stu, is the Tecnosky 125 on the high objective-side for the naked Lunt BF1800 CaK filter or do you add an objective-mask for F-stopping the light-down somewhat ??

Terry


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Re: Lunt Cak b1800 straight through module

Post by Stardust5858 »

Carbon60 wrote: Sun Mar 14, 2021 5:24 pm Hi Nigella,

I use the Lunt B1800 CaK straight module on a Tecnosky 125 without any issues. No mods, 'just as is' works fine.

I do add a 'finessing' filter with a narrower bandpass to bring up some additional details, but this is not necessary to make the module work on the scope. That's more about tweaking...... as we do.

Stu.
Thanks Stu, appreciated.


10ft x 6ft Solar RoR with Warm Room
Lunt 60mm Double Stack HA
80ed WL+ Lunt Hershal Wedge + Badder K-Line filter.
100mm AR + Lunt b1800 Ca-K module.
Neq6 Eq Mount.

2.7m Pulsar Dome.
11in Celestron SCT + White Light Filter.
70mm AR Stellavue.
12inch OO Newtonian.
Nec6 Eq Mount.
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Re: Lunt Cak b1800 straight through module

Post by Carbon60 »

EGRAY_OBSERVATORY wrote: Sun Mar 14, 2021 5:29 pm Stu, is the Tecnosky 125 on the high objective-side for the naked Lunt BF1800 CaK filter or do you add an objective-mask for F-stopping the light-down somewhat ??

Terry
Hi Terry, I figured I'd take the risk on the 125 vs 100 mm thinking that there would be some 'latitude' in the guideline from Lunt. I don't use my MK1 eyeball anyhow, so I felt it was safe. I did keep checking the temperature of the front of the module during the first few times I used it on this scope just to get a feel for how the module was coping. It remains cool, so no worries there.

Stu.


H-alpha, WL and Ca II K imaging kit for various image scales.
Fluxgate Magnetometers (1s and 150s Cadence).
Radio meteor detector.
More images at http://www.flickr.com/photos/solarcarbon60/
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Re: Lunt Cak b1800 straight through module

Post by EGRAY_OBSERVATORY »

Thank you Stu for the informative of your knowledge of the use of your HW and a 125 objective. As you say there is likely to be a margin between the manufacturers specs and the "no-longer safe" zone.

I am currently trialling my Meade ETX-125 and a Lunt 1.25" HW, with still more experiments to perform when able, I did find that an objective-mask of around 60 - 80mm seemed appropriate for imaging, but that could also depend on the 'seeing-conditions' to a small extent.

The HW was only mildly-warm, but no doubt the outside air-temperature of around 10-degsC., would make a substantial-difference there.

I would suggest that any visual-use of any HW and/or filter arrangement with any specific telescope, really needs to be commercially-tested to assess the safety of a visual purpose, as we only have one pair of eye-balls to be protected. Not to mention that the telescope itself needs to be able to handle any Solar-heating effect... Imaging of course is a much safer-way - with perhaps the camera only being in the 'line of fire'...

Terry


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Re: Lunt Cak b1800 straight through module

Post by EGRAY_OBSERVATORY »

I meant to add Stu, that it will be most unlikely that I would want to use my Lunt Ha and CaK BF's with the ETX-125, as that scope is only intended to be for WL - in any case...

Cheers
Terry


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Re: Lunt Cak b1800 straight through module

Post by marktownley »

EGRAY_OBSERVATORY wrote: Mon Mar 15, 2021 6:56 pm I am currently trialling my Meade ETX-125 and a Lunt 1.25" HW,
Be careful! You will melt the secondary spot. I would only recommend a full aperture filter with a Mak, not a rear mounted solution.


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Re: Lunt Cak b1800 straight through module

Post by EGRAY_OBSERVATORY »

Thank you Mark for that all important comment and indeed I already have an ORION full aperture Glass Solar Filter for the 125.

Obviously to use the HW, would quite definitely required F-stopping-down to say 40mm or below for the ETX-125, but will take note of your comment...

Regards
Terry


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Re: Lunt Cak b1800 straight through module

Post by Stardust5858 »

Another question re: Lunt b1800 cak module. Do I still need to use an aperture mask on my 80ed. Currently I'm using my 80ed with a 60mm aperture mask with my baader k-line filter for imaging.


10ft x 6ft Solar RoR with Warm Room
Lunt 60mm Double Stack HA
80ed WL+ Lunt Hershal Wedge + Badder K-Line filter.
100mm AR + Lunt b1800 Ca-K module.
Neq6 Eq Mount.

2.7m Pulsar Dome.
11in Celestron SCT + White Light Filter.
70mm AR Stellavue.
12inch OO Newtonian.
Nec6 Eq Mount.
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Re: Lunt Cak b1800 straight through module

Post by marktownley »

Stardust5858 wrote: Tue Mar 23, 2021 10:52 pm Another question re: Lunt b1800 cak module. Do I still need to use an aperture mask on my 80ed. Currently I'm using my 80ed with a 60mm aperture mask with my baader k-line filter for imaging.
I would. It will reduce spherical aberration which will provide a cleaner image, the filter will be presented with a longer f-ratio which will give greater contrast, it will be more seeing friendly, and, when imaging there will be less under-sampling assuming you will be doing full disks with your 178.


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Re: Lunt Cak b1800 straight through module

Post by Stardust5858 »

marktownley wrote: Wed Mar 24, 2021 6:30 am
Stardust5858 wrote: Tue Mar 23, 2021 10:52 pm Another question re: Lunt b1800 cak module. Do I still need to use an aperture mask on my 80ed. Currently I'm using my 80ed with a 60mm aperture mask with my baader k-line filter for imaging.
I would. It will reduce spherical aberration which will provide a cleaner image, the filter will be presented with a longer f-ratio which will give greater contrast, it will be more seeing friendly, and, when imaging there will be less under-sampling assuming you will be doing full disks with your 178.
Thanks Mark, really appreciate your input. Yes, I'd be using the 178. Delivery of the new Lunt b1800 Ca-K module is due end of March so getting excited, lol.


10ft x 6ft Solar RoR with Warm Room
Lunt 60mm Double Stack HA
80ed WL+ Lunt Hershal Wedge + Badder K-Line filter.
100mm AR + Lunt b1800 Ca-K module.
Neq6 Eq Mount.

2.7m Pulsar Dome.
11in Celestron SCT + White Light Filter.
70mm AR Stellavue.
12inch OO Newtonian.
Nec6 Eq Mount.
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