Lunt LS100Tha Double Stack

Use this section to discuss "standard" Baader/Coronado/ Lunt SolarView/ Daystar, etc… filters, cameras and scopes. No mods, just questions/ answers and reviews.
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Re: Lunt LS100Tha Double Stack

Post by DeepSolar64 »

Thanks all of you for you inputs and suggestions. I have a lot to wrap my head around. I do like the idea of a longer focal length instrument like the Coronado SM II 90DS. But I could also modify my Celestron 102 achromat for solar using the suggested filters as Astrograph has suggested. That scope is nearly an f10 and would give nice magnification. I currently use it for white light with an Altair wedge when seeing permits.

I still like the versatility of the Lunt 80. But how much different, better, will it be than my Coronado 60?

My Losmandy AZ8 would easily hold the weight of a Coronado 90 or a Lunt 100. It'll hold 35 pounds per side!

James


Lunt 8x32 SUNoculars
Orion 70mm Solar Telescope
Celestron AstroMaster Alt/Az Mount
Meade Coronado SolarMax II 60 DS
Meade Coronado SolarMax II 90 DS
Meade Coronado AZS Alt/Az Mount
Astro-Tech AT72EDII with Altair solar wedge
Celestron NexStar 102GT with Altair solar wedge
Losmandy AZ8 Alt/Az Mount
Sky-Watcher AZGTI Alt-Az GoTo mount
Cameras: ZWO ASI178MM, PGR Grasshopper, PGR Flea
Lunt, Coronado, TeleVue, Orion and Meade eyepieces

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Re: Lunt LS100Tha Double Stack

Post by Astrograph »

Your Celestron 102 would work well. You would just use it with a 3x telecentric. The only caveat is the quality of the focuser on the Celestron. Because of the length of the optical train there can be a danger of tilt with lightweight focusers. This will cause a system to go off band.


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Re: Lunt LS100Tha Double Stack

Post by Highbury Mark »

Must be a better replacement focuser for the Celestron 102 which would handle a Solar Spectrum set up. Though once stocks of the dedicated LS100 finally sell out, you’ll be buying a 4” ED scope as part of the modular Lunt package. I wonder how many observers actually don’t want a modular solar scope though?
Can’t argue with Rupert’s analysis of solar ha options here in the U.K. I’ve just bought the double stacked 70mm Solarscope package for not a huge amount more than the price of the LS80 DS B1800 FT.


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Re: Lunt LS100Tha Double Stack

Post by DeepSolar64 »

I could probably find a Crayford two speed or FeatherTouch focuser to fit it. A FeatherTouch ironically would cost more than the instrument itself would!

I would prefer a dedicated solar refractor over a modular scope because I already am well equipped for nighttime observing. But I would not outright reject a scope because of a modular design, unless that design dramatically increases the cost of the scope.

Are Solar Spectrum and Solarscope etalons available in the US and at what increased cost compared to Lunt and Coronado?


Lunt 8x32 SUNoculars
Orion 70mm Solar Telescope
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Meade Coronado SolarMax II 60 DS
Meade Coronado SolarMax II 90 DS
Meade Coronado AZS Alt/Az Mount
Astro-Tech AT72EDII with Altair solar wedge
Celestron NexStar 102GT with Altair solar wedge
Losmandy AZ8 Alt/Az Mount
Sky-Watcher AZGTI Alt-Az GoTo mount
Cameras: ZWO ASI178MM, PGR Grasshopper, PGR Flea
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Re: Lunt LS100Tha Double Stack

Post by marktownley »

DeepSolar64 wrote: Sat May 02, 2020 5:10 am I could probably find a Crayford two speed or FeatherTouch focuser to fit it. A FeatherTouch ironically would cost more than the instrument itself would!
I've done this on a couple of my scopes, don't worry it's perfectly normal!


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Re: Lunt LS100Tha Double Stack

Post by Astrograph »

Solar Spectrum is based in the US.

An SS based scope is only modular because it uses a conventional scope. If you want to use it just for solar or even Ha there is nothing to stop you. The fact remains the core scope and the filter are better quality than an off the shelf Solar Telescope and price will always be less compared to a similar aperture pure Solar Telescope.


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Re: Lunt LS100Tha Double Stack

Post by DeepSolar64 »

Astrograph wrote: Sat May 02, 2020 11:29 am Solar Spectrum is based in the US.

An SS based scope is only modular because it uses a conventional scope. If you want to use it just for solar or even Ha there is nothing to stop you. The fact remains the core scope and the filter are better quality than an off the shelf Solar Telescope and price will always be less compared to a similar aperture pure Solar Telescope.
Awesome! I will have to do more research on Solar Spectrum and how to fit the ERF in front of the scope's objective.


Lunt 8x32 SUNoculars
Orion 70mm Solar Telescope
Celestron AstroMaster Alt/Az Mount
Meade Coronado SolarMax II 60 DS
Meade Coronado SolarMax II 90 DS
Meade Coronado AZS Alt/Az Mount
Astro-Tech AT72EDII with Altair solar wedge
Celestron NexStar 102GT with Altair solar wedge
Losmandy AZ8 Alt/Az Mount
Sky-Watcher AZGTI Alt-Az GoTo mount
Cameras: ZWO ASI178MM, PGR Grasshopper, PGR Flea
Lunt, Coronado, TeleVue, Orion and Meade eyepieces

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Re: Lunt LS100Tha Double Stack

Post by DeepSolar64 »

It looks like I might be going Lunt after all. Meade Coronado is discontinuing the SM II line of scopes. I still am considering converting my Celestron over but the heated etalon method is a bit discouraging, the tilt-tuned and pressure tuned systems are more user friendly to a fairly novice person as myself and of course do not require electrical power therefore not requiring a wall plug or batteries and do not respond as quickly as the other tuning methods. Also F30 is terribly long. It would be very high-power only, limiting it's use considerably in so-so seeing. The SM II 90 with it's larger aperture and longer focal length was a compromise. It could give full-disc images AND good high power views. Ahhh. Dern it. Still thinking....

Modular Lunt 100 DS is really pricey. So is the Coronado SM III 90 DS. I might end up doing nothing and staying with my SM II 60 DS.

James


Lunt 8x32 SUNoculars
Orion 70mm Solar Telescope
Celestron AstroMaster Alt/Az Mount
Meade Coronado SolarMax II 60 DS
Meade Coronado SolarMax II 90 DS
Meade Coronado AZS Alt/Az Mount
Astro-Tech AT72EDII with Altair solar wedge
Celestron NexStar 102GT with Altair solar wedge
Losmandy AZ8 Alt/Az Mount
Sky-Watcher AZGTI Alt-Az GoTo mount
Cameras: ZWO ASI178MM, PGR Grasshopper, PGR Flea
Lunt, Coronado, TeleVue, Orion and Meade eyepieces

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Re: Lunt LS100Tha Double Stack

Post by Montana »

Always good to take a deep breath and keep thinking, you never know a nice second hand one may turn up :)

Alexandra


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Re: Lunt LS100Tha Double Stack

Post by DeepSolar64 »

Montana wrote: Sun May 03, 2020 6:00 pm Always good to take a deep breath and keep thinking, you never know a nice second hand one may turn up :)

Alexandra
So true. Or a closeout sale. On Lunt or Coronado!!

JP


Lunt 8x32 SUNoculars
Orion 70mm Solar Telescope
Celestron AstroMaster Alt/Az Mount
Meade Coronado SolarMax II 60 DS
Meade Coronado SolarMax II 90 DS
Meade Coronado AZS Alt/Az Mount
Astro-Tech AT72EDII with Altair solar wedge
Celestron NexStar 102GT with Altair solar wedge
Losmandy AZ8 Alt/Az Mount
Sky-Watcher AZGTI Alt-Az GoTo mount
Cameras: ZWO ASI178MM, PGR Grasshopper, PGR Flea
Lunt, Coronado, TeleVue, Orion and Meade eyepieces

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Re: Lunt LS100Tha Double Stack

Post by DeepSolar64 »

Half the price of the SolarMax III DS or the Lunt 100MT DS!!! And marked down almost 2000 dollars!

I'm game!!

https://telescopes.net/store/solar/smt9 ... ilter.html


Lunt 8x32 SUNoculars
Orion 70mm Solar Telescope
Celestron AstroMaster Alt/Az Mount
Meade Coronado SolarMax II 60 DS
Meade Coronado SolarMax II 90 DS
Meade Coronado AZS Alt/Az Mount
Astro-Tech AT72EDII with Altair solar wedge
Celestron NexStar 102GT with Altair solar wedge
Losmandy AZ8 Alt/Az Mount
Sky-Watcher AZGTI Alt-Az GoTo mount
Cameras: ZWO ASI178MM, PGR Grasshopper, PGR Flea
Lunt, Coronado, TeleVue, Orion and Meade eyepieces

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Re: Lunt LS100Tha Double Stack

Post by Highbury Mark »

If you’re happy with the weight (and ideally are able to send the scope back if you’re not happy with the performance), that’s some deal!


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Re: Lunt LS100Tha Double Stack

Post by DeepSolar64 »

It's not a grab and go, that's for sure but I have the SM II 60 for that and my Losmandy mount will easily hold it. No problem there. The dealer is reputable and the scope comes with a five-year warranty.

I hope they are as good as Stephen says they are. I ordered one just a few minutes ago.

James


Lunt 8x32 SUNoculars
Orion 70mm Solar Telescope
Celestron AstroMaster Alt/Az Mount
Meade Coronado SolarMax II 60 DS
Meade Coronado SolarMax II 90 DS
Meade Coronado AZS Alt/Az Mount
Astro-Tech AT72EDII with Altair solar wedge
Celestron NexStar 102GT with Altair solar wedge
Losmandy AZ8 Alt/Az Mount
Sky-Watcher AZGTI Alt-Az GoTo mount
Cameras: ZWO ASI178MM, PGR Grasshopper, PGR Flea
Lunt, Coronado, TeleVue, Orion and Meade eyepieces

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Re: Lunt LS100Tha Double Stack

Post by Rojas522 »

Good for you!


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Re: Lunt LS100Tha Double Stack

Post by DeepSolar64 »

Rojas522 wrote: Mon May 04, 2020 2:01 am Good for you!
Thank you. I just hope my decision is a good one. Coronado is discontinuing these scopes and my other alternatives were considerably pricier. The " bang for the buck " factor should be high here. I see a lot of people on here who use Coronado etalons on custom built scopes and mods but don't see near as many " stock " scopes in use. Lunt seems more popular on stock instruments but they are expensive. Lunt is discontinuing it's old line and going modular and Coronado is doing away with the SolarMax II line. I knew I would have to find a sale or buy one used on these instruments and I found this SMII 90 DS marked way down. So I jumped on it. I'll see how it goes.


Lunt 8x32 SUNoculars
Orion 70mm Solar Telescope
Celestron AstroMaster Alt/Az Mount
Meade Coronado SolarMax II 60 DS
Meade Coronado SolarMax II 90 DS
Meade Coronado AZS Alt/Az Mount
Astro-Tech AT72EDII with Altair solar wedge
Celestron NexStar 102GT with Altair solar wedge
Losmandy AZ8 Alt/Az Mount
Sky-Watcher AZGTI Alt-Az GoTo mount
Cameras: ZWO ASI178MM, PGR Grasshopper, PGR Flea
Lunt, Coronado, TeleVue, Orion and Meade eyepieces

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Re: Lunt LS100Tha Double Stack

Post by marktownley »

Great stuff! Think you'll like!


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Re: Lunt LS100Tha Double Stack

Post by Highbury Mark »

Fantastic - congratulations! Should be an awesome scope.


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Re: Lunt LS100Tha Double Stack

Post by DeepSolar64 »

It was a deal. Discounted wayyy off. It won't replace my smaller Coronado, it's far more portable with much easier set up. But it should do much better when the disc is active enough to warrant setting it up. It's like the C102 with the wedge. It outperforms the Orion 70 but I don't bother using it unless the sun has spots to see!


Lunt 8x32 SUNoculars
Orion 70mm Solar Telescope
Celestron AstroMaster Alt/Az Mount
Meade Coronado SolarMax II 60 DS
Meade Coronado SolarMax II 90 DS
Meade Coronado AZS Alt/Az Mount
Astro-Tech AT72EDII with Altair solar wedge
Celestron NexStar 102GT with Altair solar wedge
Losmandy AZ8 Alt/Az Mount
Sky-Watcher AZGTI Alt-Az GoTo mount
Cameras: ZWO ASI178MM, PGR Grasshopper, PGR Flea
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Re: Lunt LS100Tha Double Stack

Post by marktownley »

Make sure you post some pics when it arrives!


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Re: Lunt LS100Tha Double Stack

Post by DeepSolar64 »

Will do!!


Lunt 8x32 SUNoculars
Orion 70mm Solar Telescope
Celestron AstroMaster Alt/Az Mount
Meade Coronado SolarMax II 60 DS
Meade Coronado SolarMax II 90 DS
Meade Coronado AZS Alt/Az Mount
Astro-Tech AT72EDII with Altair solar wedge
Celestron NexStar 102GT with Altair solar wedge
Losmandy AZ8 Alt/Az Mount
Sky-Watcher AZGTI Alt-Az GoTo mount
Cameras: ZWO ASI178MM, PGR Grasshopper, PGR Flea
Lunt, Coronado, TeleVue, Orion and Meade eyepieces

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Re: Lunt LS100Tha Double Stack

Post by DeepSolar64 »

It Came today!! I few tiny breaks in the clouds tempted me to set up and tune it but to no avail.



Unboxed.JPG
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SMII90Fr.JPG (115.19 KiB) Viewed 3829 times
SMII90.JPG
SMII90.JPG (202.83 KiB) Viewed 3829 times
90 and 102.JPG
90 and 102.JPG (158.91 KiB) Viewed 3829 times
James


Lunt 8x32 SUNoculars
Orion 70mm Solar Telescope
Celestron AstroMaster Alt/Az Mount
Meade Coronado SolarMax II 60 DS
Meade Coronado SolarMax II 90 DS
Meade Coronado AZS Alt/Az Mount
Astro-Tech AT72EDII with Altair solar wedge
Celestron NexStar 102GT with Altair solar wedge
Losmandy AZ8 Alt/Az Mount
Sky-Watcher AZGTI Alt-Az GoTo mount
Cameras: ZWO ASI178MM, PGR Grasshopper, PGR Flea
Lunt, Coronado, TeleVue, Orion and Meade eyepieces

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Re: Lunt LS100Tha Double Stack

Post by JochenM »

Congratulations with the new toy, James.

I hope you get to try it out soon.


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Re: Lunt LS100Tha Double Stack

Post by marktownley »

Lurvely!!!!!!


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Re: Lunt LS100Tha Double Stack

Post by DeepSolar64 »

I tried it out briefly in Single Stack setting the tuning peg. I was stunned. I could see every prom GONG shows around the disc. One showed really nice detail. And I could actually see the spicule layer!!! Clouds moved in before I could put the DS etalon back on and tune it.


Lunt 8x32 SUNoculars
Orion 70mm Solar Telescope
Celestron AstroMaster Alt/Az Mount
Meade Coronado SolarMax II 60 DS
Meade Coronado SolarMax II 90 DS
Meade Coronado AZS Alt/Az Mount
Astro-Tech AT72EDII with Altair solar wedge
Celestron NexStar 102GT with Altair solar wedge
Losmandy AZ8 Alt/Az Mount
Sky-Watcher AZGTI Alt-Az GoTo mount
Cameras: ZWO ASI178MM, PGR Grasshopper, PGR Flea
Lunt, Coronado, TeleVue, Orion and Meade eyepieces

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Re: Lunt LS100Tha Double Stack

Post by Rojas522 »

Awesome!!


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Re: Lunt LS100Tha Double Stack

Post by Highbury Mark »

Excellent! And what a day to get your first view of proms through the SM90 - today was quite a show. Good idea to try in single stack first. I have to wait a little longer for my new set up, but glad you had a great first light


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Re: Lunt LS100Tha Double Stack

Post by Solar B »

The big gold scope looks great ... I think your gonna have a lot of fun with it.

I'm most jealous again 👽 :mrgreen:

Brian

Hang on though I think you can only use the factory DS Coronados in DS mode (not SS)

as the internal etalon does not have an ERF ... I'm sure this is the case with my SM60IIDS

but the advantage of these set ups is that they offer much brighter DS views than

those using 2 ERF ( in DS mode you only require one ERF )

Brian


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Re: Lunt LS100Tha Double Stack

Post by DeepSolar64 »

I read that the ERF to the internal etalon is in the coatings on the refractor’s objective lens in a similar fashion to the AiryLab HaT ERF coatings on the corrector lens of their Celestron SCTs. I cannot remember where I read that. But it makes sense and legally they could not sell something unsafe and plus a lot of people buy and observe with the Coronado SS scopes. SS often does better with prominences. I think the blocking filter also has some ability to block IR/UV energy.


Lunt 8x32 SUNoculars
Orion 70mm Solar Telescope
Celestron AstroMaster Alt/Az Mount
Meade Coronado SolarMax II 60 DS
Meade Coronado SolarMax II 90 DS
Meade Coronado AZS Alt/Az Mount
Astro-Tech AT72EDII with Altair solar wedge
Celestron NexStar 102GT with Altair solar wedge
Losmandy AZ8 Alt/Az Mount
Sky-Watcher AZGTI Alt-Az GoTo mount
Cameras: ZWO ASI178MM, PGR Grasshopper, PGR Flea
Lunt, Coronado, TeleVue, Orion and Meade eyepieces

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Re: Lunt LS100Tha Double Stack

Post by Solar B »

I'd prefer some clarification on that ... there are clear objectives with ERFs by other manufacturers

but I recall reading on CN 10 years ago or more that some of the factory

DS Coronados did not have an ERF to the internal scope , around this time they were switching

from 2 external to 1 internal & 1 external etalon and one could send the scope back to Coronado

to have an internal etalon installed ( this being before the introduction of the SMII)

It could be the ERF is further into the scopes assembly to like a PST , however I've always

just used mine in DS mode as is my preference and the BFs are

trimming filters that will only omit 656 nm.

However having said all that looking at the Coronado manual again there is nothing to suggest that

you cannot use the scope in SS mode.


Brian


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Re: Lunt LS100Tha Double Stack

Post by Montana »

:hamster: :hamster: :hamster: :hamster: :hamster:


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Re: Lunt LS100Tha Double Stack

Post by marktownley »

Solar B wrote: Tue May 05, 2020 10:59 pm Hang on though I think you can only use the factory DS Coronados in DS mode (not SS)

as the internal etalon does not have an ERF ... I'm sure this is the case with my SM60IIDS

but the advantage of these set ups is that they offer much brighter DS views than

those using 2 ERF ( in DS mode you only require one ERF )
If there was any concerns it would say in the instruction manual. You're talking about the older SMi series Brian, this is one of the newer versions of the SMii series - dull annealed tube opposed to brass tube. Mine is one of the older versions of the SMii series and that has no ERF (internal or external) and brass tube. The manual with doesn't state anything about it being unsafe to use in single stack configuration.


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Re: Lunt LS100Tha Double Stack

Post by Solar B »

I'm none the wiser Mark ?

Yes I recall the original otas were brass , mine is the newer (cheaper) finish , so where abouts

in the assembly is the ERF ... as they are obviously normally red or have a mirrored finish ,

you say yours is an older SMII or is it an SMI without ERF to the OTA so I take it this means

it's a DS configuration only 🤔

I'm just trying to establish where the ERF is ... as stated there is nothing in my manual

to suggest it is unsafe in SS mode 🤷

Brian


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Re: Lunt LS100Tha Double Stack

Post by marktownley »

The purpose of the red (RG630) ERF on the double stack unit is to keep it thermally stable and stop it going off band. There is no RG630 in the ota of the Coronados, the main lens may have some coating - don't know without testing, i'll get my hand held spectroscope on the case later on if I get the scope out.

So, light goes through objective and then next thing it goes through is the etalon, this produces a series of constructive and destructive interference which reduces throughput. There's the numbers for this somewhere on the forum on a thread, can't remember where without having a good search. The Blocking filter (ITF and blocker itself) then acts as the final line of filtration.

My scope is the SM90ii, this very one https://www.skyatnightmagazine.com/revi ... telescope/ (with quite a few mods from me now).


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Re: Lunt LS100Tha Double Stack

Post by DeepSolar64 »

Yours is an earlier model II. It looks like it still has the brass anodized OTA. While I like the color of mine, not sure if it is some kind of duller anodization or more likely a good powder-paint coating I like the shiny brass tube better. It's more polished...get the pun???.. :)


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Re: Lunt LS100Tha Double Stack

Post by Solar B »

I see Pete tested it Mark (he used to image with an DSSF70 as I recall) beautiful scope !!

Funnily I read this review only last week as was considering one

Yeah the stand alone SMII 60/90s OTAs do not have the red rg630 erfs but must have

a means of rejection , if you can check your 90s objective that would be great.

Some of the solarscope objectives did not have sufficient IR blocking as they would go

off band if tracking for a couple of hours as my SV50 used to ... Bob did however highlight this

to Ken some time ago (where is Bob these days ?)

It's ok I've just gotten my head round the interference process , plate flatness and parallelism

Probably will need someone to explain the FWHM graph to me again

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Re: Lunt LS100Tha Double Stack

Post by DeepSolar64 »

I found a review of an earlier model Coronado SolarMax II by Stephen Ramsden. The only visible difference I see in this scope and mine is that this one still had the brass anodized tube. Mine has the powder-painted golden tube finish. He does mention the objective having an ERF coating on it.

http://www.stephenramsden.com/solarastr ... -10-23.pdf

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Re: Lunt LS100Tha Double Stack

Post by marktownley »

Solar B wrote: Thu May 07, 2020 10:20 am if you can check your 90s objective that would be great.
Ok, so I checked yesterday the scope with a hand held spectroscope. Visually there was no difference with the spectrum through the scope and the spectrum of the sky. So, I would suggest any blocking that may (or may not) exist is out of the visible spectrum range. Looks like all blocking is done by a combination of the etalon itself and the blocking filter unit.


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Re: Lunt LS100Tha Double Stack

Post by Solar B »

Thanks Mark .. I doubt the etalon itself would reduce the transmission enough by bouncing it

around having to cope with that kind of intensity ... I was thinking the erf could be by the BF like the PST

but of course the SMs are all in a regular diagonal format .. I reckon I'll stick with the 60 in DS mode

for the time being.

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Re: Lunt LS100Tha Double Stack

Post by marktownley »

They would be safe else coronado wouldn't sell them. Does show the importance of making sure the ITF in the blocker if replaced is replaced with an ITF and not a 7 or 35nm Ha filter, as there would be little or no blocking above about 1500nm.


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Re: Lunt LS100Tha Double Stack

Post by DeepSolar64 »

Could an 1.25" eyepiece mounted UV/IR filter be used to give one added protection from UV/IR wavelengths visually at the eyepiece?


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Re: Lunt LS100Tha Double Stack

Post by marktownley »

DeepSolar64 wrote: Sun May 10, 2020 6:55 pm Could an 1.25" eyepiece mounted UV/IR filter be used to give one added protection from UV/IR wavelengths visually at the eyepiece?
Absolutely yes


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Re: Lunt LS100Tha Double Stack

Post by DeepSolar64 »

I will certainly get one of these. Any suggestions?


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Re: Lunt LS100Tha Double Stack

Post by marktownley »

I use a Baader, but any of them should be fine, just double check the transmission is up at 656nm.


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Re: Lunt LS100Tha Double Stack

Post by DeepSolar64 »

Thanks Mark!


Lunt 8x32 SUNoculars
Orion 70mm Solar Telescope
Celestron AstroMaster Alt/Az Mount
Meade Coronado SolarMax II 60 DS
Meade Coronado SolarMax II 90 DS
Meade Coronado AZS Alt/Az Mount
Astro-Tech AT72EDII with Altair solar wedge
Celestron NexStar 102GT with Altair solar wedge
Losmandy AZ8 Alt/Az Mount
Sky-Watcher AZGTI Alt-Az GoTo mount
Cameras: ZWO ASI178MM, PGR Grasshopper, PGR Flea
Lunt, Coronado, TeleVue, Orion and Meade eyepieces

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