Stacking two external Lunt DS filters
- MAURITS
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Re: Stacking two external Lunt DS filters
I have the LS60F Ha as double stack (two pieces) used in the past but I prefer the LS60F Ha frontfilter as single stack, much nicer and clearer views.
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Re: Stacking two external Lunt DS filters
Hi MArcus...
Back when the Lunt line was launched, I bought their 50mm and 75mm etalons as well as a B1200 blocking filter. I double stacked the pair on a Celestron C102 OTA (1,000mm focal length) and once I got the hang of tuning the pair they gave great views and images. Visually, the view was on the dim side with the 50mm being the limit for light gathering.
How it would compare to the DS 60's on the Teleview scope is hard to say...personally I much prefer the double stack using the 75mm on my LS80T compared to anything I did with the double stacked external pair on the C102. Just my take on it.
Brian
Back when the Lunt line was launched, I bought their 50mm and 75mm etalons as well as a B1200 blocking filter. I double stacked the pair on a Celestron C102 OTA (1,000mm focal length) and once I got the hang of tuning the pair they gave great views and images. Visually, the view was on the dim side with the 50mm being the limit for light gathering.
How it would compare to the DS 60's on the Teleview scope is hard to say...personally I much prefer the double stack using the 75mm on my LS80T compared to anything I did with the double stacked external pair on the C102. Just my take on it.
Brian
Brian Colville
Maple Ridge Observatory
Cambray, ON Canada
Photos: https://www.flickr.com/photos/185395281@N08/albums
10'x15 Roll-off Roof Observatory
Takahashi EM400 Mount carrying:
C14 + Lunt 80ED
Deep Sky Work - ASI294MM Pro+EFW 7x36/Canon 60D (Ha mod), ONAG
Planetary Work - SBIG CFW10, ASI462MM
2.2m Diameter Dome
iOptron CEM70G Mount carrying:
Orion EON 130ED, f7 OTA for Day & Night Use
Ha Setup: Lunt LS80PT/LS75FHa/B1200Ha + Home Brew Lunt Double Stack/B1800Ha on the Orion OTA + Daystar Quantum
WL, G-Band & CaK Setup: Lunt Wedge & Lunt B1800CaK, Baader K-Line and Altair 2nm G-Band filter
ASI1600MM, ASI432MM, ASI294MM Pro, ASI174MM, ASI462MM
Maple Ridge Observatory
Cambray, ON Canada
Photos: https://www.flickr.com/photos/185395281@N08/albums
10'x15 Roll-off Roof Observatory
Takahashi EM400 Mount carrying:
C14 + Lunt 80ED
Deep Sky Work - ASI294MM Pro+EFW 7x36/Canon 60D (Ha mod), ONAG
Planetary Work - SBIG CFW10, ASI462MM
2.2m Diameter Dome
iOptron CEM70G Mount carrying:
Orion EON 130ED, f7 OTA for Day & Night Use
Ha Setup: Lunt LS80PT/LS75FHa/B1200Ha + Home Brew Lunt Double Stack/B1800Ha on the Orion OTA + Daystar Quantum
WL, G-Band & CaK Setup: Lunt Wedge & Lunt B1800CaK, Baader K-Line and Altair 2nm G-Band filter
ASI1600MM, ASI432MM, ASI294MM Pro, ASI174MM, ASI462MM
- Valery
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Re: Stacking two external Lunt DS filters
It is a mistake to use two etalons which are rated as Double stacked model (which require more tilt to come to H-a core).
The pair must be:
1. Standard LS60FHa etalon for single stack view. Require very very little to no tilt to come to H-a core. This etalon must be main etalon and installed on the objective of the telescope used.
2. Etalong rated as "Double stack" etalon. This etalon require more tilt to come to H-a core. This made specially to get rid of interreflections between the etalons.
But now another ways is even better - to get two standard etalons and install a circular polarizing filter between them.
Hope this helps.
Valery
The pair must be:
1. Standard LS60FHa etalon for single stack view. Require very very little to no tilt to come to H-a core. This etalon must be main etalon and installed on the objective of the telescope used.
2. Etalong rated as "Double stack" etalon. This etalon require more tilt to come to H-a core. This made specially to get rid of interreflections between the etalons.
But now another ways is even better - to get two standard etalons and install a circular polarizing filter between them.
Hope this helps.
Valery
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Re: Stacking two external Lunt DS filters
I'm a double SM60 external stack user....being able to rotate one etalon relative to the other is almost mandatory. I'd assume the same for two Lunt filters.
Valery, I like the theory, but where do you get optical circular filters of the size needed? Then there's the cost $$$ of a special adaptor plate.
Valery, I like the theory, but where do you get optical circular filters of the size needed? Then there's the cost $$$ of a special adaptor plate.
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Re: Stacking two external Lunt DS filters
No, they are not, there are differences between them, even in combination with the Lunt blokking filters who have differences too.
- Valery
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Re: Stacking two external Lunt DS filters
A 55mm or a 60mm circular polarizing filters are not rare at all. They are also of different quality and density. If to buy a B&W filter then it will have the best transmission and the best optical quality. It is easy to make an interface bwteen two etalons where you can make a thread to place the polarizer here.Merlin66 wrote: ↑Fri Nov 01, 2019 4:54 am I'm a double SM60 external stack user....being able to rotate one etalon relative to the other is almost mandatory. I'd assume the same for two Lunt filters.
Valery, I like the theory, but where do you get optical circular filters of the size needed? Then there's the cost $$$ of a special adaptor plate.
Valery
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.
Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.
Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.