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Solar H-Alpha & White Light Equipment

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#1 helpwanted

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Posted 30 July 2020 - 04:43 PM

I'm posting here since there is no "Solar Equipment" Thread, please move it if I missed something. I picked "Refractors" to post it in since H-Alpha scopes are refractors.

 

Hello all,
Long-time telescope user, over 40 years on the dark side of astronomy, have questions for you day dwellers, all questions relate to visual use, I have no interest in taking pictures. 

 

1: I would like to get an H-alpha, and my research has me leaning to Lunt, what is everyone thoughts compared to Coronado or Quark (unsure about size right now, either 50mm or 60mm)?

 

2: White light filters, Baader seems to be the best, glass seems to be the worst (I am aware of the Herschel wedge), correct?

 

3: White light scopes, aperture or design, which is better? For example, I have a cheap 6”f5 reflector that on the night side shows coma, yet equipped with a Baader filter I see better detail in sunspots then with a 90mm Mak with a glass filter. Does aperture matter on the Sun that much, or is it the filter that is making the difference? I would have thought the Mak would have put up a better fight for detail… I think it might have won if the moon were the target.

 

4: In follow up to Q3, if you were buying a scope for white light, would you get an 80mm APO or a 100mm Mak (with a Baader filter)?

 

5: Eyepieces for H-alpha. Do you feel there is an advantage of the Lunt or Coronado eyepieces over a simple Plossl, Ortho, or even a Nagler 6/3 Zoom?

 

6: In follow up to Q5, the Lunt Zoom? Good eyepiece or laking in the quality like standard nighttime zooms.

 

7: Planetary filters along with white light? I believe I read a green filter can help with detail on the Sun.

 

Thanks for everyone’s input.
David


Edited by helpwanted, 30 July 2020 - 04:44 PM.


#2 sg6

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Posted 30 July 2020 - 05:14 PM

I'm posting here since there is no "Solar Equipment" Thread, please move it if I missed something. I picked "Refractors" to post it in since H-Alpha scopes are refractors.

 

Hello all,
Long-time telescope user, over 40 years on the dark side of astronomy, have questions for you day dwellers, all questions relate to visual use, I have no interest in taking pictures. 

 

1: I would like to get an H-alpha, and my research has me leaning to Lunt, what is everyone thoughts compared to Coronado or Quark (unsure about size right now, either 50mm or 60mm)?

 

2: White light filters, Baader seems to be the best, glass seems to be the worst (I am aware of the Herschel wedge), correct?

 

3: White light scopes, aperture or design, which is better? For example, I have a cheap 6”f5 reflector that on the night side shows coma, yet equipped with a Baader filter I see better detail in sunspots then with a 90mm Mak with a glass filter. Does aperture matter on the Sun that much, or is it the filter that is making the difference? I would have thought the Mak would have put up a better fight for detail… I think it might have won if the moon were the target.

 

4: In follow up to Q3, if you were buying a scope for white light, would you get an 80mm APO or a 100mm Mak (with a Baader filter)?

 

5: Eyepieces for H-alpha. Do you feel there is an advantage of the Lunt or Coronado eyepieces over a simple Plossl, Ortho, or even a Nagler 6/3 Zoom?

 

6: In follow up to Q5, the Lunt Zoom? Good eyepiece or laking in the quality like standard nighttime zooms.

 

7: Planetary filters along with white light? I believe I read a green filter can help with detail on the Sun.

 

Thanks for everyone’s input.
David

1) Your choice.

2) Baader films seems the most popular, I have a glass one and it works fine.

3&4) I use refractors have a Mak but never really use it, too narrow for ease of use. So cannot really say.
5) Seriously expect no great difference. The eyepiece would need "tuned" to Ha to be better and cannot see what other then the AR coating would really impact. Maybe they do have coating that transmit optimally at 656nm. But that is all I would think.

6) Don't like zooms, prefer individual eyepieces. Just been trying a spotting scope with a zoom arrangement - my eyes are still recovering. Change zoom, find target again. Not pleasant.

7) The Green is a Continium filter (odd name) actually 540nm, not sure of the width. Expect you need a reasonably narrow band, so not a Wratten Glass filter. Not sure they work well with a front filter. Usually with a Herschel Wedge. Don't expect a narrow Ha to work, seems it isn't like that



#3 Marc-Andre

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Posted 30 July 2020 - 05:18 PM

I think the "Solar Observing and Imaging" forum is your best shot to get your questions addressed, and educate yourself on solar observing equipment.  I only have "Thousand Oak" filters, and a recently acquired Herschel wedge which I've not yet used, so my experience is limited or just beginning.

 

https://www.cloudyni...ng-and-imaging/


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#4 descott12

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Posted 30 July 2020 - 05:22 PM

 

1: I would like to get an H-alpha, and my research has me leaning to Lunt, what is everyone thoughts compared to Coronado or Quark (unsure about size right now, either 50mm or 60mm)?

>> I have the Lunt 50 mm and I love it. Lunt customer service is really great. If I had to do it again, I would get something a little bigger (60 or 80 mm) but the price goes way up fast, especially for a double stack.  Also realize that Meade is on somewhat shakey ground right now with bankruptcy, so I personally would not be spending alot of money for a scope that may or may not have support. But again, just my 2 cents on that.

 

 

6: In follow up to Q5, the Lunt Zoom? Good eyepiece or laking in the quality like standard nighttime zooms.

>> I have the Lunt zoom and I think it works very well and it is reasonably priced. However, I don't have anything to compare to but it is really nice to zoom in and out and not have to mess with changing eyepieces.

 

7: Planetary filters along with white light? I believe I read a green filter can help with detail on the Sun.

>> At the advice of one of the experts here, I purchased the 610 Longpass filter. I have not had a chance to compare with or without so not sure how much it helps with my setup.

 

 



#5 gnowellsct

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Posted 30 July 2020 - 05:26 PM

There is a solar observing section where these things are often discussed.  But it would be good to discuss them here so that other night refractor users get an idea that they too could do solar h-alpha.  So I'm hoping the thread stays in refractors but that you check out the solar observing forum.  Don't get confused with the solar SYSTEM observing forum.  

 

I'm flirting with the idea of a Baader Herschel Wedge for white light.  Opinions vary as to whether this is better than a film.

 

There isn't a lot going on with the sun in white light these days.

 

H-alpha config.  Long time solar photographer Marty (Malveaux) gets excellent results with an achromat.  The idea is that in solar h-alpha you're only working in one wavelength and therefore you don't need the difficult correction and expensive optical glass that goes into an apo.   I *cannot* argue with the results that Marty gets!

 

For whatever reason, my personal views of the sun have always been best in top o' the line apos.  This includes h-alpha viewing at NEAF and my own personal experiments with a 92 mm and 130 mm triplets vs 102 mm f/6.5 doublet.  

 

Lunt makes specialized telescopes that just do the sun.  I have looked through one of these optimized for prominences.  As advertised, it did better on prominences than my chromosphere h-alpha filter which is very good on prominences but not as good as the Lunt.  On the other hand to my eye the detail on the solar disk was better in the Quark chromosphere.   So all things considered I felt I was getting the value I was paying for.  The Quark chromosphere advertises as being "good" on prominences but more optimized for surface details.   There is a prominence Quark but it seems to be for run of the mill observing the best of the two cases is with the chromosphere for overall performance.

 

On the other hand with Quark you can get the system that can be used in a white light telescope.  So your night time scope can be your daytime scope.  

 

That's a very attractive combination of qualities. 

 

With regard to zooms, that's not so useful in solar IME.  The solar etalons are quirky and you get advised (for example) with the quark to use 30 and 40 mm.

You should figure on getting the eyepieces the solar vendor recommends.  If you want a zoom get a zoom, if it works that is OK, if it is good for night viewing that is OK too.  But don't get it specifically for solar.

 

One thing is that the cost of these systems "all in" tends to have extras.   If you buy the Daystar Quark you may need to purchase the UV/IR filter and it requires telecentric barlows (not ordinary barlows) which in English translates to:  Buy the 4x and 2x power mates.  As it happens I have found these two power mates to be handy to have around.  I don't regret it but converting my 92 mm f/6.9 to h-alpha capability cost about $2k.

 

You need a power supply.  I have a humongo power supply for night viewing but a smaller one would do just for h-alpha.  Oddly, with the Quark you need power to heat the etalon.  I don't know about the Lunt.

 

A polarizing filter is handy item, improves solar disk detail in h-alpha.

 

Here's a view of the 92 mm doing solar.  In my night time viewing I mount it on other scopes:

 

cff fast tpod set up - cn size.jpg

 

 

 

 


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#6 photoracer18

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Posted 30 July 2020 - 05:46 PM

I have been solar observing for close to 50 years with all kinds of equipment. From my experience the best white light views come from a Herschel Wedge by a margin that is small but can be seen. As for objective filters Baader film is very good because the material is thin and does not adversely affect the optics. As for glass it depends on the quality of the glass just like any filter. For Ha I would say there is no substitute for price, the more it costs the better the performance. Sort of like refractors in general also.


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#7 helpwanted

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Posted 30 July 2020 - 07:14 PM

Thank you for all the replies, I’m happily reading all of them



#8 LDW47

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Posted 30 July 2020 - 07:35 PM

I'm posting here since there is no "Solar Equipment" Thread, please move it if I missed something. I picked "Refractors" to post it in since H-Alpha scopes are refractors.

 

Hello all,
Long-time telescope user, over 40 years on the dark side of astronomy, have questions for you day dwellers, all questions relate to visual use, I have no interest in taking pictures. 

 

1: I would like to get an H-alpha, and my research has me leaning to Lunt, what is everyone thoughts compared to Coronado or Quark (unsure about size right now, either 50mm or 60mm)?

 

2: White light filters, Baader seems to be the best, glass seems to be the worst (I am aware of the Herschel wedge), correct?

 

3: White light scopes, aperture or design, which is better? For example, I have a cheap 6”f5 reflector that on the night side shows coma, yet equipped with a Baader filter I see better detail in sunspots then with a 90mm Mak with a glass filter. Does aperture matter on the Sun that much, or is it the filter that is making the difference? I would have thought the Mak would have put up a better fight for detail… I think it might have won if the moon were the target.

 

4: In follow up to Q3, if you were buying a scope for white light, would you get an 80mm APO or a 100mm Mak (with a Baader filter)?

 

5: Eyepieces for H-alpha. Do you feel there is an advantage of the Lunt or Coronado eyepieces over a simple Plossl, Ortho, or even a Nagler 6/3 Zoom?

 

6: In follow up to Q5, the Lunt Zoom? Good eyepiece or laking in the quality like standard nighttime zooms.

 

7: Planetary filters along with white light? I believe I read a green filter can help with detail on the Sun.

 

Thanks for everyone’s input.
David

I bought a Coronado PST and a Baader WL filter system, mounted on my 90mm refractor, both from B&H for $550 US & around $60 US respectively and they both perform beautifully ! And I am as green as you are when it comes to solar work, lol ! Clear solar skiys and good luck !


Edited by LDW47, 30 July 2020 - 07:39 PM.


#9 LDW47

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Posted 30 July 2020 - 07:38 PM

I'm posting here since there is no "Solar Equipment" Thread, please move it if I missed something. I picked "Refractors" to post it in since H-Alpha scopes are refractors.

 

Hello all,
Long-time telescope user, over 40 years on the dark side of astronomy, have questions for you day dwellers, all questions relate to visual use, I have no interest in taking pictures. 

 

1: I would like to get an H-alpha, and my research has me leaning to Lunt, what is everyone thoughts compared to Coronado or Quark (unsure about size right now, either 50mm or 60mm)?

 

2: White light filters, Baader seems to be the best, glass seems to be the worst (I am aware of the Herschel wedge), correct?

 

3: White light scopes, aperture or design, which is better? For example, I have a cheap 6”f5 reflector that on the night side shows coma, yet equipped with a Baader filter I see better detail in sunspots then with a 90mm Mak with a glass filter. Does aperture matter on the Sun that much, or is it the filter that is making the difference? I would have thought the Mak would have put up a better fight for detail… I think it might have won if the moon were the target.

 

4: In follow up to Q3, if you were buying a scope for white light, would you get an 80mm APO or a 100mm Mak (with a Baader filter)?

 

5: Eyepieces for H-alpha. Do you feel there is an advantage of the Lunt or Coronado eyepieces over a simple Plossl, Ortho, or even a Nagler 6/3 Zoom?

 

6: In follow up to Q5, the Lunt Zoom? Good eyepiece or laking in the quality like standard nighttime zooms.

 

7: Planetary filters along with white light? I believe I read a green filter can help with detail on the Sun.

 

Thanks for everyone’s input.
David

What I have found I like to use is a zoom ep with a variable polarizing filter attached, it gives a bit of versatility and a bit of a challenge to your solar viewing times ! Just my found preference but maybe not the experts in this field ? 



#10 helpwanted

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Posted 30 July 2020 - 11:55 PM

I’m the original poster, I see my thread was moved over to this form, but please keep in mind my questions are all about visual and nothing about photography or imaging, or what ever it’s called now!



#11 jimandlaura26

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Posted 31 July 2020 - 12:38 AM

DD41A02A-9F24-48E6-9409-A24DE72E061D.jpeg I'm posting here since there is no "Solar Equipment" Thread, please move it if I missed something. I picked "Refractors" to post it in since H-Alpha scopes are refractors.

 

Hello all,
Long-time telescope user, over 40 years on the dark side of astronomy, have questions for you day dwellers, all questions relate to visual use, I have no interest in taking pictures. 

 

1: I would like to get an H-alpha, and my research has me leaning to Lunt, what is everyone thoughts compared to Coronado or Quark (unsure about size right now, either 50mm or 60mm)?

 

2: White light filters, Baader seems to be the best, glass seems to be the worst (I am aware of the Herschel wedge), correct?

 

3: White light scopes, aperture or design, which is better? For example, I have a cheap 6”f5 reflector that on the night side shows coma, yet equipped with a Baader filter I see better detail in sunspots then with a 90mm Mak with a glass filter. Does aperture matter on the Sun that much, or is it the filter that is making the difference? I would have thought the Mak would have put up a better fight for detail… I think it might have won if the moon were the target.

 

4: In follow up to Q3, if you were buying a scope for white light, would you get an 80mm APO or a 100mm Mak (with a Baader filter)?

 

5: Eyepieces for H-alpha. Do you feel there is an advantage of the Lunt or Coronado eyepieces over a simple Plossl, Ortho, or even a Nagler 6/3 Zoom?

 

6: In follow up to Q5, the Lunt Zoom? Good eyepiece or laking in the quality like standard nighttime zooms.

 

7: Planetary filters along with white light? I believe I read a green filter can help with detail on the Sun.

 

Thanks for everyone’s input.
David

1. Have owned 2 Lunt scopes (50 and 60mm) and 1 Coronado (40mm). Lunt mechanical and optical quality are great assets. Outstanding features include Pressure Tuner and FeatherTouch Focuser. Double stacking also makes a significant improvement. I owned Coronado PST originally, performed well mechanically and optically, with some minor adjustments required during use because solar disk was not evenly illuminated.

2. I used Thousand Oaks glass white light filters. Good performance. Lunt Herschel wedge provides superior resolution of sunspot features.

3. Aperture improvements matter, particularly on low end sizes, and especially with double stacking where image dims. Other questions you have concerning scopes I cannot comment on - too many variables here, and no direct experience with these specifics. I would add though that more aperture also buys you a bit more image scale - increased magnification.

4.  80mm apo.

5. Eyepiece experience has shown good performance across a variety of designs and brands. Currently use Vixen 8-24mm zoom.

7. Not so much experience here - but i would judge that quality of filter is important. Most inexpensive color filters are poor performers (including for nighttime observation). Recommend Baader brand - pay more but much higher quality.

 

Good Luck!


Edited by jimandlaura26, 31 July 2020 - 02:52 PM.


#12 MalVeauX

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Posted 31 July 2020 - 09:32 AM

Heya,

 

It comes down to budget and expectations. Then it comes down to your day time seeing conditions. The idea of larger aperture can be interesting in solar, but not if your day time seeing conditions are 3~4" and a fuzzy mess. This is why a lot of solar options are small aperture. Also, our star is so close to us that a mere 60mm aperture can resolve the major features really well, even visually. You don't need a big aperture like for planets. Think more like how lunar observation is with smaller apertures, you can see a ton with small apertures because its so close. Solar visual is the same as solar system in general, just with the idea that its big and close and very very bright of course and then sprinkle some safety on top to avoid any eyeball damage.

 

Hydrogen alpha is the upper chromosphere, and a red wavelength, 656nm so it helps with calming poor seeing (which is all day in daytime). A dedicated sub-angstrom filtered HA scope is going to cost hundreds for the most basic to over $1k for even a small 60mm dedicated scope. However, it's worth it. The chromosphere is the most dynamic crazy hell-fire landscape you can view off-Earth. It changes in minutes to hours. It changes completely daily. This is where you'll see the prominences, filaments, plages, etc that are so explosive. While most of these dedicated scopes are refractors (because of the simplicity of total transmission of lenses and the ease of thermal handling as lenses do not absorb heat, they're ideal instruments for solar) it can be configured on a mirror based instrument too (this is common for large aperture setups). The mirror systems require full aperture thermal handling filters and are incredibly expensive to get and pretty much custom (to see an example of commercial options, this would be Airy Labs HAT or Baader's Tri-Band SCT). I don't recommend these big aperture mirror options for visual though. For entering this, I would stick to a refractor design for simplicity and portability and cost.

 

Visual hydrogen alpha doesn't need a big aperture to be stunning, but I will make a special note that a double-stacked (dual etalon) filter system is ideal because the contrast difference is extremely important visually and makes a significant difference. I would sacrifice aperture for double-stacking with respect to visual of hydrogen alpha. Not all systems can be double stacked, so you have to pay attention to this. Also, cost goes up fast, but again, it makes a big difference and is worth it.

 

Photosphere viewing, also called "white light" can be done rather inexpensively with solar film (like Baader visual grade ND5.0 solar film, it's totally safe and very durable despite the idea of it) or a herschel wedge (this only works with refractors). Photosphere viewing is full spectrum, so this means you can have chromatic aberration on the limb, just like the moon or anything else if using a telescope design prone to CA (like fast achromatic refractors; not an issue for ED/APO or mirrors). Overall its not a big deal as it's only the limb, but some people care about that and its only for the photosphere. Everything else will be narrowband and will have zero CA as an option. Any scope design works here.

 

There are other layers to the sun of course (Calcium, Magnesium, Sodium, etc), but really I wouldn't go beyond hydrogen alpha and any wavelength of the photosphere for visual.

 

For practicality I would point your attention to Lunt's modular design scopes. This allows you to get a small 60mm ED refractor that will be able to swap between HA and photosphere visually with one scope and it still will be useful for any subject at night too, being an ED refractor. Fantastic travel scope in that way, good for everything, simple and small.

 

https://luntsolarsys...dular-telescope

 

If that's not budget friendly, consider Lunt's upcoming 40mm option.

 

https://luntsolarsys...0mm-telescopes/

 

I wouldn't go for a PST at this time, because of this new superior offering from Lunt at a similar price. These are ok devices but have the most compromise of anything there is out there.

 

I wouldn't go for a Solarmax at this time, with Meade's legal status and bankruptcy stuff being in limbo with respect to having support later on if something is wrong. The Solarmax III series are nice, modular on a base achromatic refractor with a good crayford focuser (far superior to the old SM2 series in that way); front mounted is ideal and you can double stack, prices are good. But again, it's up to you whether you want to get something at this price point with a questionable future support from, considering them filing bankruptcy after being sued by Orion.

 

I wouldn't go for a Daystar/SolarSpectrum right now (Rear mounted etalons) unless your goal is the biggest aperture for the cost you can manage (seeing requirements skyrocket). They're good, excellent even, but they require power sources to control the bandpass with heat (pressure). This would be the least expensive way to get a huge aperture for solar on a budget, due to rear mounted design. Allowing a 6 inch refractor to be used without a front mounted thermal filter to handle the heat even (though its recommended frankly over 120mm aperture to get a front mounted thermal handling filter). Your seeing would need to handle these scales to bother going this direction. Yes you can put it in a smaller scope too, but you cannot double stack these, so it's always a single stack view and low contrast due to that. For visual, I would highly suggest a double stack view for high contrast, it's simply unforgettable.

 

Very best,


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#13 LDW47

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Posted 31 July 2020 - 01:29 PM

Heya,

 

It comes down to budget and expectations. Then it comes down to your day time seeing conditions. The idea of larger aperture can be interesting in solar, but not if your day time seeing conditions are 3~4" and a fuzzy mess. This is why a lot of solar options are small aperture. Also, our star is so close to us that a mere 60mm aperture can resolve the major features really well, even visually. You don't need a big aperture like for planets. Think more like how lunar observation is with smaller apertures, you can see a ton with small apertures because its so close. Solar visual is the same as solar system in general, just with the idea that its big and close and very very bright of course and then sprinkle some safety on top to avoid any eyeball damage.

 

Hydrogen alpha is the upper chromosphere, and a red wavelength, 656nm so it helps with calming poor seeing (which is all day in daytime). A dedicated sub-angstrom filtered HA scope is going to cost hundreds for the most basic to over $1k for even a small 60mm dedicated scope. However, it's worth it. The chromosphere is the most dynamic crazy hell-fire landscape you can view off-Earth. It changes in minutes to hours. It changes completely daily. This is where you'll see the prominences, filaments, plages, etc that are so explosive. While most of these dedicated scopes are refractors (because of the simplicity of total transmission of lenses and the ease of thermal handling as lenses do not absorb heat, they're ideal instruments for solar) it can be configured on a mirror based instrument too (this is common for large aperture setups). The mirror systems require full aperture thermal handling filters and are incredibly expensive to get and pretty much custom (to see an example of commercial options, this would be Airy Labs HAT or Baader's Tri-Band SCT). I don't recommend these big aperture mirror options for visual though. For entering this, I would stick to a refractor design for simplicity and portability and cost.

 

Visual hydrogen alpha doesn't need a big aperture to be stunning, but I will make a special note that a double-stacked (dual etalon) filter system is ideal because the contrast difference is extremely important visually and makes a significant difference. I would sacrifice aperture for double-stacking with respect to visual of hydrogen alpha. Not all systems can be double stacked, so you have to pay attention to this. Also, cost goes up fast, but again, it makes a big difference and is worth it.

 

Photosphere viewing, also called "white light" can be done rather inexpensively with solar film (like Baader visual grade ND5.0 solar film, it's totally safe and very durable despite the idea of it) or a herschel wedge (this only works with refractors). Photosphere viewing is full spectrum, so this means you can have chromatic aberration on the limb, just like the moon or anything else if using a telescope design prone to CA (like fast achromatic refractors; not an issue for ED/APO or mirrors). Overall its not a big deal as it's only the limb, but some people care about that and its only for the photosphere. Everything else will be narrowband and will have zero CA as an option. Any scope design works here.

 

There are other layers to the sun of course (Calcium, Magnesium, Sodium, etc), but really I wouldn't go beyond hydrogen alpha and any wavelength of the photosphere for visual.

 

For practicality I would point your attention to Lunt's modular design scopes. This allows you to get a small 60mm ED refractor that will be able to swap between HA and photosphere visually with one scope and it still will be useful for any subject at night too, being an ED refractor. Fantastic travel scope in that way, good for everything, simple and small.

 

https://luntsolarsys...dular-telescope

 

If that's not budget friendly, consider Lunt's upcoming 40mm option.

 

https://luntsolarsys...0mm-telescopes/

 

I wouldn't go for a PST at this time, because of this new superior offering from Lunt at a similar price. These are ok devices but have the most compromise of anything there is out there.

 

I wouldn't go for a Solarmax at this time, with Meade's legal status and bankruptcy stuff being in limbo with respect to having support later on if something is wrong. The Solarmax III series are nice, modular on a base achromatic refractor with a good crayford focuser (far superior to the old SM2 series in that way); front mounted is ideal and you can double stack, prices are good. But again, it's up to you whether you want to get something at this price point with a questionable future support from, considering them filing bankruptcy after being sued by Orion.

 

I wouldn't go for a Daystar/SolarSpectrum right now (Rear mounted etalons) unless your goal is the biggest aperture for the cost you can manage (seeing requirements skyrocket). They're good, excellent even, but they require power sources to control the bandpass with heat (pressure). This would be the least expensive way to get a huge aperture for solar on a budget, due to rear mounted design. Allowing a 6 inch refractor to be used without a front mounted thermal filter to handle the heat even (though its recommended frankly over 120mm aperture to get a front mounted thermal handling filter). Your seeing would need to handle these scales to bother going this direction. Yes you can put it in a smaller scope too, but you cannot double stack these, so it's always a single stack view and low contrast due to that. For visual, I would highly suggest a double stack view for high contrast, it's simply unforgettable.

 

Very best,

A very comprehensive write up !



#14 LDW47

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Posted 31 July 2020 - 01:34 PM

Do think my trying a variable polarizing filter helps to compensate the contrast for my not having a double stacked scope ! I have the basic PST and I have been using a zoom ep in conjunction with the variable and it seems to calm the brightness down while helping with contrast. I have been meaning to get some comments from the experts about that. 



#15 MalVeauX

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Posted 31 July 2020 - 01:45 PM

Do think my trying a variable polarizing filter helps to compensate the contrast for my not having a double stacked scope ! I have the basic PST and I have been using a zoom ep in conjunction with the variable and it seems to calm the brightness down while helping with contrast. I have been meaning to get some comments from the experts about that. 

Heya,

 

Some may think they're having better contrast, but they're not really. The reason an HA image has low contrast is because there's too much photosphere (off band) light coming through. The photosphere is many times more bright than the chromosphere and even at 1 Angstrom or less there's still off-band light that bleeds through, the parasitic continuum. If you imagine a rather steep transmission profile and imagine the off-band frequencies on the left/right skirt of the peak being so bright that they come through still, you can start to see why contrast is low for the on-band frequency of 656nm (HA). This is why double stacking is so important for visual, it further removes the off-band frequencies in the skirt of the transmission profile left/right of the peak of 656nm so that contrast is much higher for the on-band frequency (HA). For an exercise, consider, is the light coming through an etalon already polarized, or not? And if it's not, what does polarizing do to sub-angstrom light frequency? And what's the benefit? I ask because this is worth exploring and learning about and it absolutely matters in terms of what you end up spending your money on for what you expect to get out of it.

 

Double stacking is the best thing you can do to increase contrast. There's no free lunch. A polarized filter on a single stack will not even come close to what a double stack does for contrast.

 

Very best,


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#16 helpwanted

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Posted 31 July 2020 - 07:27 PM

Heya,

 

It comes down to budget and expectations. Then it comes down to your day time seeing conditions. The idea of larger aperture can be interesting in solar, but not if your day time seeing conditions are 3~4" and a fuzzy mess. This is why a lot of solar options are small aperture. Also, our star is so close to us that a mere 60mm aperture can resolve the major features really well, even visually. You don't need a big aperture like for planets. Think more like how lunar observation is with smaller apertures, you can see a ton with small apertures because its so close. Solar visual is the same as solar system in general, just with the idea that its big and close and very very bright of course and then sprinkle some safety on top to avoid any eyeball damage.

 

Hydrogen alpha is the upper chromosphere, and a red wavelength, 656nm so it helps with calming poor seeing (which is all day in daytime). A dedicated sub-angstrom filtered HA scope is going to cost hundreds for the most basic to over $1k for even a small 60mm dedicated scope. However, it's worth it. The chromosphere is the most dynamic crazy hell-fire landscape you can view off-Earth. It changes in minutes to hours. It changes completely daily. This is where you'll see the prominences, filaments, plages, etc that are so explosive. While most of these dedicated scopes are refractors (because of the simplicity of total transmission of lenses and the ease of thermal handling as lenses do not absorb heat, they're ideal instruments for solar) it can be configured on a mirror based instrument too (this is common for large aperture setups). The mirror systems require full aperture thermal handling filters and are incredibly expensive to get and pretty much custom (to see an example of commercial options, this would be Airy Labs HAT or Baader's Tri-Band SCT). I don't recommend these big aperture mirror options for visual though. For entering this, I would stick to a refractor design for simplicity and portability and cost.

 

Visual hydrogen alpha doesn't need a big aperture to be stunning, but I will make a special note that a double-stacked (dual etalon) filter system is ideal because the contrast difference is extremely important visually and makes a significant difference. I would sacrifice aperture for double-stacking with respect to visual of hydrogen alpha. Not all systems can be double stacked, so you have to pay attention to this. Also, cost goes up fast, but again, it makes a big difference and is worth it.

 

Photosphere viewing, also called "white light" can be done rather inexpensively with solar film (like Baader visual grade ND5.0 solar film, it's totally safe and very durable despite the idea of it) or a herschel wedge (this only works with refractors). Photosphere viewing is full spectrum, so this means you can have chromatic aberration on the limb, just like the moon or anything else if using a telescope design prone to CA (like fast achromatic refractors; not an issue for ED/APO or mirrors). Overall its not a big deal as it's only the limb, but some people care about that and its only for the photosphere. Everything else will be narrowband and will have zero CA as an option. Any scope design works here.

 

There are other layers to the sun of course (Calcium, Magnesium, Sodium, etc), but really I wouldn't go beyond hydrogen alpha and any wavelength of the photosphere for visual.

 

For practicality I would point your attention to Lunt's modular design scopes. This allows you to get a small 60mm ED refractor that will be able to swap between HA and photosphere visually with one scope and it still will be useful for any subject at night too, being an ED refractor. Fantastic travel scope in that way, good for everything, simple and small.

 

https://luntsolarsys...dular-telescope

 

If that's not budget friendly, consider Lunt's upcoming 40mm option.

 

https://luntsolarsys...0mm-telescopes/

 

I wouldn't go for a PST at this time, because of this new superior offering from Lunt at a similar price. These are ok devices but have the most compromise of anything there is out there.

 

I wouldn't go for a Solarmax at this time, with Meade's legal status and bankruptcy stuff being in limbo with respect to having support later on if something is wrong. The Solarmax III series are nice, modular on a base achromatic refractor with a good crayford focuser (far superior to the old SM2 series in that way); front mounted is ideal and you can double stack, prices are good. But again, it's up to you whether you want to get something at this price point with a questionable future support from, considering them filing bankruptcy after being sued by Orion.

 

I wouldn't go for a Daystar/SolarSpectrum right now (Rear mounted etalons) unless your goal is the biggest aperture for the cost you can manage (seeing requirements skyrocket). They're good, excellent even, but they require power sources to control the bandpass with heat (pressure). This would be the least expensive way to get a huge aperture for solar on a budget, due to rear mounted design. Allowing a 6 inch refractor to be used without a front mounted thermal filter to handle the heat even (though its recommended frankly over 120mm aperture to get a front mounted thermal handling filter). Your seeing would need to handle these scales to bother going this direction. Yes you can put it in a smaller scope too, but you cannot double stack these, so it's always a single stack view and low contrast due to that. For visual, I would highly suggest a double stack view for high contrast, it's simply unforgettable.

 

Very best,

Thank you for all this detailed information!


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#17 LDW47

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Posted 31 July 2020 - 08:37 PM

Heya,

 

Some may think they're having better contrast, but they're not really. The reason an HA image has low contrast is because there's too much photosphere (off band) light coming through. The photosphere is many times more bright than the chromosphere and even at 1 Angstrom or less there's still off-band light that bleeds through, the parasitic continuum. If you imagine a rather steep transmission profile and imagine the off-band frequencies on the left/right skirt of the peak being so bright that they come through still, you can start to see why contrast is low for the on-band frequency of 656nm (HA). This is why double stacking is so important for visual, it further removes the off-band frequencies in the skirt of the transmission profile left/right of the peak of 656nm so that contrast is much higher for the on-band frequency (HA). For an exercise, consider, is the light coming through an etalon already polarized, or not? And if it's not, what does polarizing do to sub-angstrom light frequency? And what's the benefit? I ask because this is worth exploring and learning about and it absolutely matters in terms of what you end up spending your money on for what you expect to get out of it.

 

Double stacking is the best thing you can do to increase contrast. There's no free lunch. A polarized filter on a single stack will not even come close to what a double stack does for contrast.

 

Very best,

Great info, I will read it several more times to get it all together in my mind and maybe ask a couple of more ?’s. Before I start thinking double stacking should I maybe wait for this new scope to hit the market, I believe from Lunt ?



#18 helpwanted

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Posted 31 July 2020 - 09:21 PM

I’m going to ask a question about that 40 mm Lunt as well, specifications on the web page say it is .65 A, does that mean you really don’t need a double stack since they are usually .5 A?


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#19 MalVeauX

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Posted 31 July 2020 - 11:37 PM

Great info, I will read it several more times to get it all together in my mind and maybe ask a couple of more ?’s. Before I start thinking double stacking should I maybe wait for this new scope to hit the market, I believe from Lunt ?

Depends on what you want. Lunt's new 40mm is an entry level scope. It will have a double stack option per their description eventually. If your budget is tight, this is one to watch. 40mm still shows lots of detail on solar, it resolves all the major features in HA. Just remember its an entry device, not ideal for imaging if that's a consideration. Also not sure how binoviewers will work on it, but likely will work fine with a glass path corrector. If you're considering a 60mm option, then by all means, don't wait. If you were already considering options like the PST, then yes, the Lunt 40 is worth waiting for.

 

I’m going to ask a question about that 40 mm Lunt as well, specifications on the web page say it is .65 A, does that mean you really don’t need a double stack since they are usually .5 A?

Unfortunately that number doesn't mean anything. There's no standard in the industry at all with respect to uniformity, finesse, or bandpass. The bandpass is largely meaningless after 1A. Having 0.3A, 0.5A, 0.6A, 0.7A, doesn't mean anything unfortunately. It just means the center peak transmission centered on 656.28nm is lower and sharper. But there will still be parasitic continuum leaking through, so there will be a double limb even with a $16,000 Quantum 0.3A PE filter for example. The high contrast of a good etalon doesn't come from its bandpass value, it comes from its finesse, the sharpness of its peak transmission in the profile curve. The more light that is leaking in from other frequencies in the skirt of the profile is what kills contrast and produces the double limb effect. A second etalon solves this by heavily cutting transmission enough to surpress the skirt of the transmission profile, with both filters tuned to the same frequency allowing 656.28nm to come through only. That produces the highest contrast and it's truly unreal the difference in contrast. The only other way is with a 1A blocking filter, but you won't find that for less than $1500+ and it will be a custom order and small. So naturally 99.9% of everyone has two etalons when trying to get high contrast and double stacking them.

 

Two cheap 1A filters or 0.7A filters double stacked will have way more contrast than a single super expensive 0.3A filter will. I can't stress this enough. That number doesn't mean anything at all. Far more important would be to see the transmission profile, if provided one, to see what is really going on with the particular etalon as they're all completely different and there's copy variation.

 

Very best,



#20 kecked

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Posted 01 August 2020 - 11:53 AM

I have the Lunt 60mm double stack from the first run they made.  The view is assume!

i just got a film filter for a 102ed Astro tech today....raining of course.

 

what I want to observe are granulae.  I want to zoom in on them.  Any suggestions?  I heard a 540nm filter helps with this.  I can see them in the lint but can’t get the resolution.

 

i have a Meade ar6 I could outfit too.  Not sure hpwhat is required to “zoom” in or if its even possible in my instruments visually.




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