Changing from Solar filters to solar wedge.

[LDW1]

My points only, first the difference in cost between a wedge at $400+ C and a an excellent solar film filter at $100-$150 C is a differential that many won't bear, while still getting a great view ie the lack of need to. I upgraded to a 1.25" / 2" wedge only because I wanted to and didn't mind spending. Secondly I have never heard but would like to hear how many have, unfortunately, had a front filter fall off with the ensuing eye damage or maybe it is just a theoretical talk that it could happen ?? Nothing wrong with differences of opinion but ' the proof is in the pudding ' as it should be. I don't condem either methods having been there with both and there are probably thousands of excellent solar viewers, very experienced solar viewers out there that are more than happy with the film, its quite obvious.  Lets hear of some actual happenings !

[LDW1]

35 minutes ago, johninderby said:

When seeing is average not a huge difference in performance between Baader film and a wedge but with great seeing you can really push the mag with a wedge and see more detail.

Best white light I’ve ever had is with a wedge and my 125 APO. Wonder if the scope used makes for different experiences using a front mounted filter and a wedge.

Yes if a front mounted filter were to fail you would get the full suns light whereas if a wedge were to fail it simply wouldn’t pass any light to the eyepiece. However never heard of a front mounted filter failing but have heard of the filter falling off.

As you should know, with solar viewing, the seeing can fluctuate in seconds depending on heated air currents, it is constant change a bit different than nite viewing. I use all fast refractors at relative low powers, many times with a good zoom lens and a couple of filters to enhance the contrast and reduce the brightness.

[Louis D]

18 minutes ago, Stu said:

I suspect it does. I think if you use a fast achro with too much SA then it will mask the performance benefits of a wedge at high power, so you won’t see much difference. Use a decent long focal length achro (eg 102mm f11) or a good apo and the results would likely be different.

With a fast achro, the Baader Solar Continuum filter would help immensely since it filters out the unfocused ends of the spectrum leaving only the sharp green portion around 540nm:

Even a #56 Green filter would probably help immensely to increase image sharpness in an achro:

Passing only 50% of the green light isn't a big deal with solar viewing since you're attenuating it so much anyway.

[Stu]

27 minutes ago, LDW1 said:

As you should know, with solar viewing, the seeing can fluctuate in seconds depending on heated air currents, it is constant change a bit different than nite viewing. I use all fast refractors at relative low powers, many times with a good zoom lens and a couple of filters to enhance the contrast and reduce the brightness.

As per my previous post with your use case I suspect there is little benefit in a wedge over film. The main benefit for me comes when using a slower achro or apo at high power to really show the detail. I’ve posted previously about the fact that even a blank disk can be interesting to view with a high power setup in good or excellent seeing conditions.

 

24 minutes ago, Louis D said:

With a fast achro, the Baader Solar Continuum filter would help immensely since it filters out the unfocused ends of the spectrum leaving only the sharp green portion around 540nm:

Even a #56 Green filter would probably help immensely to increase image sharpness in an achro:

Passing only 50% of the green light isn't a big deal with solar viewing since you're attenuating it so much anyway.

CA isn’t the issue with fast achros for solar, Spherical Abberation is the problem. If you have a lot of SA as is not in common in these scopes then it kills the fine detail in granulation and ARs at high powers, and that’s where the fun in white light observing is for me.

[johninderby]

Quote fron Stu

“As per my previous post with your use case I suspect there is little benefit in a wedge over film. The main benefit for me comes when using a slower achro or apo at high power to really show the detail. I’ve posted previously about the fact that even a blank disk can be interesting to view with a high power setup in good or excellent seeing conditions.”

Exactly what I have found. 👍🏻

[Carl Au]

29 minutes ago, johninderby said:

Quote fron Stu

“As per my previous post with your use case I suspect there is little benefit in a wedge over film. The main benefit for me comes when using a slower achro or apo at high power to really show the detail. I’ve posted previously about the fact that even a blank disk can be interesting to view with a high power setup in good or excellent seeing conditions.”

Exactly what I have found. 👍🏻

I concur.

On another matter where did you get that shield from, I could use one of those.

[johninderby]

32 minutes ago, Carl Au said:

I concur.

On another matter where did you get that shield from, I could use one of those.

Mine is an old Astro Engineering one but Widescreen has a very similar looking one. 

https://www.widescreen-centre.co.uk/emc-sb2-solar-shield.html

[Carl Au]

Thank you, appreciated 

[MortonH]

Based on positive reviews I ordered the visual version of the Hercules wedge through AliExpress. It cost about AU$230 including shipping and GST.

https://www.aliexpress.com/i/4001204285379.html

On opening the package I discovered:

- the 'included' polarising filter is missing

- the main body enclosing the prism is loose at every joint

I was able to solve the second issue by tightening the various tiny Allen bolts so it now feels secure.

 

AliExpress has offered a partial refund for the missing filter so I guess if it performs ok then I'll probably accept it.

Edited April 7, 2023 by MortonH
More info

[Louis D]

Don't even think about looking through it at the sun without the variable polarizing filter in place.  The image is way too bright for human eyes to tolerate.  I think it defaults to somewhere around an ND3 to ND4 brightness without additional filtration.  You need to be at about ND5 for safety sake.

I'm sorry your experience with it has not been as positive as mine has been.  Everything was nice and tight and still is, and it came with the variable polarizer.

It needs about an additional ND2's worth of dimming to be usable.  I bought a Svbony ND3, but it was too much.  A moon filter wasn't enough.  I decided that the variable polarizer was still the best option.

I set the variable polarizer to just about the brightest I can stand the image to be by trial and error (just take a quick peek off axis through the eyepiece to gauge the brightness).  I then do final brightness adjustment by rotating the eyepiece in the holder to take advantage of the partial polarization caused by the wedge.  Put another way, I dim down the view by eyepiece rotation to whatever level seems best for whatever feature I'm observing at that moment.  If I can't get it dim enough, I'll take out the eyepiece and adjust the variable polarizer downward in transmission amount.

I would go ahead an order in a variable polarizer from AliExpress or ebay.  They're not that expensive in the 1.25" size.

[LDW1]

4 hours ago, MortonH said:

Based on positive reviews I ordered the visual version of the Hercules wedge through AliExpress. It cost about AU$230 including shipping and GST.

https://www.aliexpress.com/i/4001204285379.html

On opening the package I discovered:

- the 'included' polarising filter is missing

- the main body enclosing the prism is loose at every joint

I was able to solve the second issue by tightening the various tiny Allen bolts so it now feels secure.

 

AliExpress has offered a partial refund for the missing filter so I guess if it performs ok then I'll probably accept it.

Is the polarizing filter not already inside the workings of the wedge and all you have to do is turn the polarizing ring to vary it ?  My 2" Altair Astro came that way, already installed. How did you notice it was missing, open up the wedge ?

[LDW1]

52 minutes ago, Louis D said:

Don't even think about looking through it at the sun without the variable polarizing filter in place.  The image is way too bright for human eyes to tolerate.  I think it defaults to somewhere around an ND3 to ND4 brightness without additional filtration.  You need to be at about ND5 for safety sake.

I'm sorry your experience with it has not been as positive as mine has been.  Everything was nice and tight and still is, and it came with the variable polarizer.

It needs about an additional ND2's worth of dimming to be usable.  I bought a Svbony ND3, but it was too much.  A moon filter wasn't enough.  I decided that the variable polarizer was still the best option.

I set the variable polarizer to just about the brightest I can stand the image to be by trial and error (just take a quick peek off axis through the eyepiece to gauge the brightness).  I then do final brightness adjustment by rotating the eyepiece in the holder to take advantage of the partial polarization caused by the wedge.  Put another way, I dim down the view by eyepiece rotation to whatever level seems best for whatever feature I'm observing at that moment.  If I can't get it dim enough, I'll take out the eyepiece and adjust the variable polarizer downward in transmission amount.

I would go ahead an order in a variable polarizer from AliExpress or ebay.  They're not that expensive in the 1.25" size.

The variable polarizer has nothing to do with safety, its just to vary the brightness, tone it down same as when viewing the moon. Even if it is too bright its safe, don't give a wrong information. The 1.25" models don't have variables, my 2 Lunts sure didn't.

[Louis D]

8 minutes ago, LDW1 said:

The variable polarizer has nothing to do with safety, its just to vary the brightness, tone it down same as when viewing the moon. Even if it is too bright its safe, don't give a wrong information. The 1.25" models don't have variables, my 2 Lunts sure didn't.

Safe maybe, but usable or comfortable, not really.  Where did I say it wasn't safe?  I said it's intolerable.  There are no features to be seen at that level of brightness.  It's just basically a featureless white circle of intense brightness.  There are plenty of features to see on the moon without a filter of any sort.

In fact, I had to jerk my head away when I first tried looking through it without further filtration.  It's nothing like viewing the moon without a moon filter.  I've never experienced that sense of impending eye damage while viewing the moon.

Maybe this wedge works fine in Canada without further filtration, but the noon summer sun in Texas is just too bright for my liking without additional filtration.  It might be fine with the rising sun in a Texas winter, who knows?  My horizon views are blocked, so I wouldn't know.

[LDW1]

2 hours ago, Louis D said:

Safe maybe, but usable or comfortable, not really.  Where did I say it wasn't safe?  I said it's intolerable.  There are no features to be seen at that level of brightness.  It's just basically a featureless white circle of intense brightness.  There are plenty of features to see on the moon without a filter of any sort.

In fact, I had to jerk my head away when I first tried looking through it without further filtration.  It's nothing like viewing the moon without a moon filter.  I've never experienced that sense of impending eye damage while viewing the moon.

Maybe this wedge works fine in Canada without further filtration, but the noon summer sun in Texas is just too bright for my liking without additional filtration.  It might be fine with the rising sun in a Texas winter, who knows?  My horizon views are blocked, so I wouldn't know.

Many experienced solar viewers just use a no. 56-58 green filter to reduce brightness and increase contrast as a great alternative. I use them all. Just more info for the poster ie. performance vs safety ! And there are other factors to a great view of the sun , at any given point in the day, as we all know.

Edited April 7, 2023 by LDW1

[Louis D]

You're right.  A narrow notch filter or dim to dark color filter actually works much better without the additional ND filtering.  I've done that with my Optica b/c line filters that only transmit 30% over a <10nm bandwidth at best.  They're much too dim to be useful otherwise.

[MortonH]

19 hours ago, LDW1 said:

Is the polarizing filter not already inside the workings of the wedge and all you have to do is turn the polarizing ring to vary it ?  My 2" Altair Astro came that way, already installed. How did you notice it was missing, open up the wedge ?

The ND3 filter is installed at the bottom of the eyepiece holder as expected but the polariser is supposed to be separate. I unscrewed the eyepiece holder but couldn't remove the filter. I'm pretty sure the polariser isn't installed in there as well.

[MortonH]

19 hours ago, LDW1 said:

Is the polarizing filter not already inside the workings of the wedge and all you have to do is turn the polarizing ring to vary it ?  My 2" Altair Astro came that way, already installed. How did you notice it was missing, open up the wedge ?

I shouldn't need a variable polariser as the prism polarises the light. I just need a single polariser to attach to the eyepiece and then I can rotate the whole eyepiece to vary the brightness.

When I had a Lunt wedge a few years ago I had a continuum filter instead of a polariser but I was hoping to avoid a green image this time.

[LDW1]

2 hours ago, MortonH said:

I shouldn't need a variable polariser as the prism polarises the light. I just need a single polariser to attach to the eyepiece and then I can rotate the whole eyepiece to vary the brightness.

When I had a Lunt wedge a few years ago I had a continuum filter instead of a polariser but I was hoping to avoid a green image this time.

I understand, with a 1.25" wedge there is no variable polarizer built in but with a 2" it is built in with a nurled adjustment ring part of the upper stem of the wedge. My 1.25" vs 2" wedges are like that so I do use a seperate variable polarizer with the 1.25" and it makes a big, big difference. Then sometimes I like to use just the green filters for a change because they do give a different contrast. And they are only a fraction of the cost of the continum filter yet do the same job.

[LDW1]

As a bit of an aside to this topic, I enjoy using all of my wedges with my Svbony 10-30 zoom ep, for me a zoom is the perfect combination for WL and Ha viewing and basic ap. You don't have to worry about FOV issues.

[Louis D]

4 hours ago, MortonH said:

The ND3 filter is installed at the bottom of the eyepiece holder as expected but the polariser is supposed to be separate. I unscrewed the eyepiece holder but couldn't remove the filter. I'm pretty sure the polariser isn't installed in there as well.

Correct.  Mine arrived in a bubble wrapped zip bag as I recall.  It was just tucked in with the wedge to the side.

4 hours ago, MortonH said:

I shouldn't need a variable polariser as the prism polarises the light. I just need a single polariser to attach to the eyepiece and then I can rotate the whole eyepiece to vary the brightness.

When I had a Lunt wedge a few years ago I had a continuum filter instead of a polariser but I was hoping to avoid a green image this time.

Yes, a single polarizer will work, but you have to get the rotation position angle right before you can start observing.  This can be a pain in the eye when swapping eyepieces while solar observing.  Setting a variable polarizer to a certain maximum brightness allows you to start observing right away when swapping eyepieces.  If it's still too bright, rotating the eyepiece allows for further dimming just as with a single polarizer.

Also, since the wedge is not at the Brewster angle, you're not getting perfect polarization, so full dimming with a single polarizer may not be possible.  Thus, you might not be able to dim it enough for your liking, but the second polarizer in the variable filter guarantees you can get there.  I'll have to try this out with a single polarizer on my Hercules wedge sometime to see how dim it can get.

Again, single or variable polarizers are quite cheap from China via AliExpress or ebay, so no worries financially about replacing the missing one.

[Mr Spock]

I've gotten used to the green of the Continuum. I might try the polariser option though to see how it compares.

[MortonH]

Today there was a break in the clouds and I tried out the wedge in a 66mm f/6 ED refractor. Since I have no additional filters right now I wore sunglasses for the first look and the view was good through a 25mm eyepiece. Removing the sunglasses turned the sun into a glowing,  featureless disk as expected.

So for now I'm satisfied and have accepted the partial refund which will cover the purchase of a GSO polariser and probably a green filter as well.

[MortonH]

13 hours ago, LDW1 said:

As a bit of an aside to this topic, I enjoy using all of my wedges with my Svbony 10-30 zoom ep, for me a zoom is the perfect combination for WL and Ha viewing and basic ap. You don't have to worry about FOV issues.

Agreed. I'll be using a zoom as well.

[MortonH]

13 hours ago, Louis D said:

Correct.  Mine arrived in a bubble wrapped zip bag as I recall.  It was just tucked in with the wedge to the side.

Yes, a single polarizer will work, but you have to get the rotation position angle right before you can start observing.  This can be a pain in the eye when swapping eyepieces while solar observing.  Setting a variable polarizer to a certain maximum brightness allows you to start observing right away when swapping eyepieces.  If it's still too bright, rotating the eyepiece allows for further dimming just as with a single polarizer.

Also, since the wedge is not at the Brewster angle, you're not getting perfect polarization, so full dimming with a single polarizer may not be possible.  Thus, you might not be able to dim it enough for your liking, but the second polarizer in the variable filter guarantees you can get there.  I'll have to try this out with a single polarizer on my Hercules wedge sometime to see how dim it can get.

Again, single or variable polarizers are quite cheap from China via AliExpress or ebay, so no worries financially about replacing the missing one.

I have a short 1.25" extension tube that I'll use between the wedge and the eyepiece. If I attach the polariser and any other filters to the extension tube I can swap eyepieces without unscrewing the filter(s). The extension tube will sit inside the eyepiece holder of the Herschel wedge with plenty of clearance above the ND filter. This is how I used my Lunt 1.25" wedge a few years ago but the only additional filter I used was  a Baader continuum. The brightness seemed ok but now I wonder if I could have improved the contrast by using a polariser as well.

I take the point that a single polariser may not be sufficient so I might buy two and put one on the extension tube and the other on the eyepiece. Since I'll be using a zoom I don't think swapping eyepieces will actually be necessary.

[Gemineyes]

I've been doing solar observing (continuum) for over 30 years. While it has become pretty much "routine", I ALWAYS remember that this is a risky endeavor, and remember safety first!!! Whatever the kit I use, I always make sure everything is a "go" before deployment.

I use routinely (depending upon instrument) either Baader AS film-equipped full aperture solar filters, or when employing refractors, my Wedges. For those that have not experienced the sun in a 120mm SD binocular, it is truly stunning, I assure you! I almost always also employ a polarizing filter on the rear end of the AS film filters on the eyepiece side. I find granulation and subtle plage structures show much more vividly using these. I have an Intes Wedge (2"), a Baader (2" Vis/Photo vintage ~2004) wedge, and an APM 2" Wedge. I use these on my Stellarvue/TMB 105 APO, my SV90T APO, and SV80ED (80mm f/7 ED doublet). I also have had a hoot playing with my Skywatcher ST120 (120mm f/5 Fraunhofer doublet achromat). While the APOs show a bit more detail, that ST120 is NO slouch! When used with my Baader FK filter (FK=fringe killer) and sometimes my IDAS P2 filter (really color balances the image!) or my Stellarvue Chroma filter (MV2, which I designed for Vic Maris), the Achromat does pretty well indeed!

Whether wedge or Baader AS-equipped, I find I personally prefer using NO 538nm green filter, and prefer the whitish image more. I also have employed a 589nm/10nm FWHM filter I procured and mounted in a custom filter cell, and use it sometimes in with the polarizer in the wedge, or aft of the film. The image is yellow, but some of the Na D-lines show in this filter, and it shows details more like a Ca-K filter - plage really stands out in that filter! 

Anyway, so long as you CHECK a front filter before aiming Sol-ward, you will be fine. Just keep little ones with sticks in their hands away from the instrument! 

Is one better than the other? Well, the wedge should edge out by a bit the Baader AS film, but with proper mounting and care in fitting the front filter, you can get very close - the big plus with the wedge is being able to tune the brightness with magnification. That is a huge advantage. Another way to achieve this with a Baader AS filter is to employ the ND3.8 photo film and use variable polarizers, or a ND4 (25%T) filter and a polarizer, or a 12.5%T (ND8) neutral filter to achieve the appropriate image brightness. By using crossed variable polarizers, one can also tune image brightness.

Is a wedge worth it? IMO, yes, but make sure that your optics are sort of "worthy" of the investment. A poorly make refractor using a wedge is not getting the full advantage it should. One can get pretty close using a properly made/crafted (not cardboard or elastic bands!!!) filter system which minimizes strain on the film mount system. Then the Baader AS film shows it capabilities. There are several AS film filters that do this. APM sells Solar EMC filters, which are superbly made! The Kendrick classic style is very nice, but sometimes they get a dud produced. Baader also has their ASTF line of filters which are also superb. 

I witnessed this past month (October 14, 2023) from Edmonton AB Canada the solar eclipse - it was partial there, not annular like in the continental US. However, using a APM 120-45SD binocular telescope at 47X using twin 14mm ES82s and polarizers (the 120s were equipped with my Solar EMC 120mm binocular filters), the views were actually surreal. We have been eclipse "poor" in North America in general and this was the first eclipse I have viewed in a bino-telescope. Well, I can tell you that the experience was superb! 3D perception of the moon "over" the sun was possible, as was pulling out fine limb edge details of the moon during the event (along with the spots, granulation, plage, etc.)!!

A LOT of fun.

My favorite solar setup I use and used during the Eclipse in October: APM 120mm, 45-degree SD APO binos with 14mm ES82s/polarizers:

Here is my most recent acquisition, my APM Wedge (mounted on my SV90T APO  - 90mm f/7 LZOS triplet - using my Skywatcher AZ5 on an Oberwerk TR3 maple tripod and mini-pier):

For either, Wedge or AS Film, I highly recommend using the best filtering you can get: Baader, B+W, APM, and Hoya are all superb choices. (for polarizers, and first two for ND3 (0.1%T) filters. 

Clear skies and loads of sunpots!

Darren