My PST CaK mod.
Re: My PST CaK mod. Help!
Hi Guys,
using two K-line filters in tandem.
If it is set up as bandpass-bandpass- ITF(MDM). This would be the way I would look at it first.
AR-bandpass -BG25-bandpass-BG25-ITF should have a BG25 window laminated to it on the back side with an AR.This was how, what Del called the 5 Ang K-line filter was assemble. We used 10 Ang. bandpasses, it wasn't 5 ang but it worked petty good. We mounted it in a tilting housing and would tilt it to maximum contrast. I would had greased them all together to keep up the transmission(which also helps with reflections ). I have found that K-line reflection are not as strong as Ha. And some times you can get away with just using blue filter glass. This approach would not work at Ha.
The other way would be to use a circular polaroid between the two bandpasses. The problem with this is the cost is going to be higher at wavelength shorter then 400nm. Then you would need a 1/4 wave plate also. If they are greased together as a unit that will help also.
The advantage here is that you are only using 20mm filters so 25mm polaroids and 1/4 wave plates might not be bad at that size.
If you have the advantage of tilting the bandpasses then by offsetting them just right should drop the HW and increase the contrast.
Try the BG25 first, Polaroid did make a UV polaroid but after they closed up it got bought up fast. So it maybe hard to find this low cost UV polaroid material.
Mark Wagner
using two K-line filters in tandem.
If it is set up as bandpass-bandpass- ITF(MDM). This would be the way I would look at it first.
AR-bandpass -BG25-bandpass-BG25-ITF should have a BG25 window laminated to it on the back side with an AR.This was how, what Del called the 5 Ang K-line filter was assemble. We used 10 Ang. bandpasses, it wasn't 5 ang but it worked petty good. We mounted it in a tilting housing and would tilt it to maximum contrast. I would had greased them all together to keep up the transmission(which also helps with reflections ). I have found that K-line reflection are not as strong as Ha. And some times you can get away with just using blue filter glass. This approach would not work at Ha.
The other way would be to use a circular polaroid between the two bandpasses. The problem with this is the cost is going to be higher at wavelength shorter then 400nm. Then you would need a 1/4 wave plate also. If they are greased together as a unit that will help also.
The advantage here is that you are only using 20mm filters so 25mm polaroids and 1/4 wave plates might not be bad at that size.
If you have the advantage of tilting the bandpasses then by offsetting them just right should drop the HW and increase the contrast.
Try the BG25 first, Polaroid did make a UV polaroid but after they closed up it got bought up fast. So it maybe hard to find this low cost UV polaroid material.
Mark Wagner
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Re: My PST CaK mod. Help!
Hi Mark
thank you very much for the insights
thank you very much for the insights
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Re: My PST CaK mod. Help!
Hi Mark,
I'm finding it difficult to find circular polarizers. Edmund and Thor have linear polarizers, although they look very expensive - $700 + USD for a 25 mm. As far as 1/4 wave plates these look to be about $500 + USD from Thor. As far as "grease," where does one find this? I assume from what you say that this would be beneficial without the aforementioned polarizer/waveplate to reduce reflections between the two, without disturbing the performance of the filters...
Best wishes,
Bob
I'm finding it difficult to find circular polarizers. Edmund and Thor have linear polarizers, although they look very expensive - $700 + USD for a 25 mm. As far as 1/4 wave plates these look to be about $500 + USD from Thor. As far as "grease," where does one find this? I assume from what you say that this would be beneficial without the aforementioned polarizer/waveplate to reduce reflections between the two, without disturbing the performance of the filters...
Best wishes,
Bob
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Re: My PST CaK mod. Help!
Slow to reply here... I double checked my measurements Valery; it's actually 110mm between the 2 CaK filters, and then roughly 50mm to the chip (slightly less than my original guess-timation!). I looked down the aperture of the 40mm scope today when I was using it, the clear diameter of the filter is 23mm, with the light cone from the objective on the filter less than this. I'm fairly confident there's no vignetting going on.Valery wrote:Hi Mark,marktownley wrote:It's roughly about 50mm from the chip.
Thanks. So, if you have a first 20mm CaK filter in 150mm + 50mm = 200mm from the camera chip and the Sun image is not a dot, then you have vignetting towards edges of the chip. Just a food for thoughts.
Valery
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Re: My PST CaK mod. Help!
Interesting stuff Mark.mdwmark wrote:Hi Guys,
using two K-line filters in tandem.
If it is set up as bandpass-bandpass- ITF(MDM). This would be the way I would look at it first.
AR-bandpass -BG25-bandpass-BG25-ITF should have a BG25 window laminated to it on the back side with an AR.This was how, what Del called the 5 Ang K-line filter was assemble. We used 10 Ang. bandpasses, it wasn't 5 ang but it worked petty good. We mounted it in a tilting housing and would tilt it to maximum contrast. I would had greased them all together to keep up the transmission(which also helps with reflections ). I have found that K-line reflection are not as strong as Ha. And some times you can get away with just using blue filter glass. This approach would not work at Ha.
The other way would be to use a circular polaroid between the two bandpasses. The problem with this is the cost is going to be higher at wavelength shorter then 400nm. Then you would need a 1/4 wave plate also. If they are greased together as a unit that will help also.
The advantage here is that you are only using 20mm filters so 25mm polaroids and 1/4 wave plates might not be bad at that size.
If you have the advantage of tilting the bandpasses then by offsetting them just right should drop the HW and increase the contrast.
Try the BG25 first, Polaroid did make a UV polaroid but after they closed up it got bought up fast. So it maybe hard to find this low cost UV polaroid material.
Mark Wagner
I tried some BG25 between the 2 bandpass filters a while ago, and while it did reduce the reflection it did not get rid of it. Admittedly the BG25 I bought was cheap, and not AR coated.
Do you have any links to the uv polaroids and 1/4 waveplates where we could get them from? It's certainly something i would like to pursue.
Thanks
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Re: My PST CaK mod. Help!
I did mean your larger telescope!marktownley wrote:Slow to reply here... I double checked my measurements Valery; it's actually 110mm between the 2 CaK filters, and then roughly 50mm to the chip (slightly less than my original guess-timation!). I looked down the aperture of the 40mm scope today when I was using it, the clear diameter of the filter is 23mm, with the light cone from the objective on the filter less than this. I'm fairly confident there's no vignetting going on.Valery wrote:Hi Mark,marktownley wrote:It's roughly about 50mm from the chip.
Thanks. So, if you have a first 20mm CaK filter in 150mm + 50mm = 200mm from the camera chip and the Sun image is not a dot, then you have vignetting towards edges of the chip. Just a food for thoughts.
Valery
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Re: My PST CaK mod. Help!
Should still be ok, all are f10...Valery wrote:I did mean your larger telescope!
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Re: My PST CaK mod. Help!
Mark,
I forgot to point out. When you grease or oil an element together make sure that you are not greasing to an AR surface.
An AR that is greased will cause internal reflection. And it even makes it worse when it is next to a reflective surface.
I should had bought as much as I could of the UV Polaroid. But I never used it that much and my suppler told me that someone else would probable start making it. This didn't happen. In the UK I see that Comar Optics sells it. But it was not cheep but still much less then the new style like Thor or Edmunds sells. The wire grid works well also but that is much more then the old Polaroid UV also.
The 1/4 wave plate, for what you want to do does not really need to be at 393nm. It could be in the low 400nm and it would still cut the reflections. The Mica ones usually cost the least. I am sure you already know that you split the axis of the polaroid and the wave plate axis to turn it into a circular polaroid.
Mark,
Did you try to tilt the BG25 1.8 deg. this is usually enough to shift the reflection out of the field. I had wedges made up just for that. The thick side and the thin directly across so the filter is tilted but it lines up flat for mounting.
With out any AR's you will always get some reflection off the ends of the windows.
There where some other companies that I found that claimed they had the UV polariod. But it cost much more then I remember paying for it. I'll keep checking to see what I can find for you
Mark Wagner
I forgot to point out. When you grease or oil an element together make sure that you are not greasing to an AR surface.
An AR that is greased will cause internal reflection. And it even makes it worse when it is next to a reflective surface.
I should had bought as much as I could of the UV Polaroid. But I never used it that much and my suppler told me that someone else would probable start making it. This didn't happen. In the UK I see that Comar Optics sells it. But it was not cheep but still much less then the new style like Thor or Edmunds sells. The wire grid works well also but that is much more then the old Polaroid UV also.
The 1/4 wave plate, for what you want to do does not really need to be at 393nm. It could be in the low 400nm and it would still cut the reflections. The Mica ones usually cost the least. I am sure you already know that you split the axis of the polaroid and the wave plate axis to turn it into a circular polaroid.
Mark,
Did you try to tilt the BG25 1.8 deg. this is usually enough to shift the reflection out of the field. I had wedges made up just for that. The thick side and the thin directly across so the filter is tilted but it lines up flat for mounting.
With out any AR's you will always get some reflection off the ends of the windows.
There where some other companies that I found that claimed they had the UV polariod. But it cost much more then I remember paying for it. I'll keep checking to see what I can find for you
Mark Wagner
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Re: My PST CaK mod. Help!
Hi Mark M.
thanks for the helpfull information
thanks for the helpfull information
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Re: My PST CaK mod. Help!
Mark,mdwmark wrote:Mark,
I forgot to point out. When you grease or oil an element together make sure that you are not greasing to an AR surface.
An AR that is greased will cause internal reflection. And it even makes it worse when it is next to a reflective surface.
I should had bought as much as I could of the UV Polaroid. But I never used it that much and my suppler told me that someone else would probable start making it. This didn't happen. In the UK I see that Comar Optics sells it. But it was not cheep but still much less then the new style like Thor or Edmunds sells. The wire grid works well also but that is much more then the old Polaroid UV also.
The 1/4 wave plate, for what you want to do does not really need to be at 393nm. It could be in the low 400nm and it would still cut the reflections. The Mica ones usually cost the least. I am sure you already know that you split the axis of the polaroid and the wave plate axis to turn it into a circular polaroid.
Mark,
Did you try to tilt the BG25 1.8 deg. this is usually enough to shift the reflection out of the field. I had wedges made up just for that. The thick side and the thin directly across so the filter is tilted but it lines up flat for mounting.
With out any AR's you will always get some reflection off the ends of the windows.
There where some other companies that I found that claimed they had the UV polariod. But it cost much more then I remember paying for it. I'll keep checking to see what I can find for you
Mark Wagner
Many thanks for your input in this field. However with my raw english I barely understand or sometime don't understand what must be done in correct CaK double stacked filter.
Is this possible to make sketches of these different realizations you have talked about?
Thanks in advance,
Valery.
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Re: My PST CaK mod. Help!
OK , I'll do some sketches, it will make is much easier to understand.
Mark W.
Mark W.
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Re: My PST CaK mod.
Edmund Optics, hard coated 394nm 10nm band pass filter finally arrived. Looked through it at a halogen bright lamp and barely see the lamp.
When I added a CaK PST yellowing filter, I saw nothing - completely dark.
Tomorrow I will make a drawing of the filters assembling. Hope that this assembly will be redy for next week and then I can start imaging in CaK line.
When I added a CaK PST yellowing filter, I saw nothing - completely dark.
Tomorrow I will make a drawing of the filters assembling. Hope that this assembly will be redy for next week and then I can start imaging in CaK line.
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Re: My PST CaK mod.
Hi Valery
that will be very interesting
that will be very interesting
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Re: My PST CaK mod.
Sounds normal to me. Double stack is even darkerValery wrote: Looked through it at a halogen bright lamp and barely see the lamp.
When I added a CaK PST yellowing filter, I saw nothing - completely dark.
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Re: My PST CaK mod.
Hi Mark,marktownley wrote:Sounds normal to me. Double stack is even darkerValery wrote: Looked through it at a halogen bright lamp and barely see the lamp.
When I added a CaK PST yellowing filter, I saw nothing - completely dark.
What the typical exposure at F/10 when you use DS? What the exposure in SS? What is your camera QE at 400nm?
Thanks?
Valery.
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Re: My PST CaK mod.
Hi Valery
Exposure at f10 DS = 1/250s
Exposure @ f10 SS = ~1/1667s
DMK31 QE @ 400nm = I have no idea! Let me know if you find out
Mark
Exposure at f10 DS = 1/250s
Exposure @ f10 SS = ~1/1667s
DMK31 QE @ 400nm = I have no idea! Let me know if you find out
Mark
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Re: My PST CaK mod.
Thank you very much, Mark!marktownley wrote:Hi Valery
Exposure at f10 DS = 1/250s
Exposure @ f10 SS = ~1/1667s
DMK31 QE @ 400nm = I have no idea! Let me know if you find out
Mark
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Re: My PST CaK mod.
Question to Mark and Walter.
I just opened the CaK PST, unscrew the first filter block, removed the second (rusted) filter and put the EO 10nm 394nm filter on the place of that rusted filter #2.
Then I looked at the sun (shines brightly and a really blue sky) and what I saw disappointed me VERY much! I saw the sun disk of pale sand color!
I expect to see nothing or deeeeeep violet disk.
When I add that rusted filter #2 - I see NOTHING.
When I look through EO 394nm filter at the sun, I see the same pale sand disk but brighter. No violet disk, as I have expected!
The question:
1. what you, friends, see when you looking on the sun through CaK PST yellowing filter and Baader K-line filter?
2. What you see when looking at the sun trough Baader K-line filer?
3. Do I see the leakage of this filter which has Optical Density about 4-5 across the spectrum (except it's bandpass) ?
The eye has very wide dynamic range and it can see the leakage and not see the radiation around 393nm.
4. Do I understand correctly that the camera (my one has 50% EQ at the 400nm) will see the 393nm radiation just fine and the leaked radiation
will not harm the sun images because this leakage is very minor and due to camera narrower dynamic range it will not be visible?
Thanks,
Valery.
I just opened the CaK PST, unscrew the first filter block, removed the second (rusted) filter and put the EO 10nm 394nm filter on the place of that rusted filter #2.
Then I looked at the sun (shines brightly and a really blue sky) and what I saw disappointed me VERY much! I saw the sun disk of pale sand color!
I expect to see nothing or deeeeeep violet disk.
When I add that rusted filter #2 - I see NOTHING.
When I look through EO 394nm filter at the sun, I see the same pale sand disk but brighter. No violet disk, as I have expected!
The question:
1. what you, friends, see when you looking on the sun through CaK PST yellowing filter and Baader K-line filter?
2. What you see when looking at the sun trough Baader K-line filer?
3. Do I see the leakage of this filter which has Optical Density about 4-5 across the spectrum (except it's bandpass) ?
The eye has very wide dynamic range and it can see the leakage and not see the radiation around 393nm.
4. Do I understand correctly that the camera (my one has 50% EQ at the 400nm) will see the 393nm radiation just fine and the leaked radiation
will not harm the sun images because this leakage is very minor and due to camera narrower dynamic range it will not be visible?
Thanks,
Valery.
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Re: My PST CaK mod.
The saga continues.
I asked my friend Max Usatov (Prague) to look at the sun through CaK PST + K-line Baader. He did so and reported that he sees deep violet sun
and through CaK PST without K-line he seems light turquoise color. Through K-line alone he sees the deep violet sun. He used CaK PST filter #1 and #2 block as is through both filters. With CaK line block (#1 + #2) I too, see the light turquoise sun. Adding to this block EO filter I see nothing.
Through EO 394nm alone I see pale sand sun - means EO leaks a lot across full spectrum - see here: http://www.edmundoptics.com/techsupport ... _65131.pdf
I asked my friend Max Usatov (Prague) to look at the sun through CaK PST + K-line Baader. He did so and reported that he sees deep violet sun
and through CaK PST without K-line he seems light turquoise color. Through K-line alone he sees the deep violet sun. He used CaK PST filter #1 and #2 block as is through both filters. With CaK line block (#1 + #2) I too, see the light turquoise sun. Adding to this block EO filter I see nothing.
Through EO 394nm alone I see pale sand sun - means EO leaks a lot across full spectrum - see here: http://www.edmundoptics.com/techsupport ... _65131.pdf
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Re: My PST CaK mod.
Hi Valery
i always see a blue disk but I'm not sure about the PST Cak #2 alone, I have to recheck tomorrow
i always see a blue disk but I'm not sure about the PST Cak #2 alone, I have to recheck tomorrow
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Re: My PST CaK mod.
Thanks, Walter for your wishes to help! If possible take a look and write down how the sun disk looks through following filters and combos.swisswalter wrote:Hi Valery
i always see a blue disk but I'm not sure about the PST Cak #2 alone, I have to recheck tomorrow
1. #1 + #2
2. #1 + #2 + K-line
3. #1 + K-line
4. #1 + half of K-line
5. K-line alone
6. K-line half
7. #2 alone
8. #2 + K-line
9. #2 + half K-line
CS
Valery.
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Re: My PST CaK mod.
Very strange! can you take a picture of the EO filter just holding it up to a light please valery.
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Re: My PST CaK mod.
A bit (very very lightly) yellowing bright mirror from both sides. Just like filter #2 in the PST CaK scope but brighter, higher reflection.marktownley wrote:Very strange! can you take a picture of the EO filter just holding it up to a light please valery.
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Re: My PST CaK mod.
Hi Valery
i found the following:
light green bright 1. #1 + #2
no go dark 2. #1 + #2 + K-line
violett 3. #1 + K-line
green bright 4. #1 + half of K-line
violett 5. K-line alone
green very bright 6. K-line half
violett, bright 7. #2 alone
dark violett 8. #2 + K-line
dark violett 9. #2 + half K-line
any conclusions ?
i found the following:
light green bright 1. #1 + #2
no go dark 2. #1 + #2 + K-line
violett 3. #1 + K-line
green bright 4. #1 + half of K-line
violett 5. K-line alone
green very bright 6. K-line half
violett, bright 7. #2 alone
dark violett 8. #2 + K-line
dark violett 9. #2 + half K-line
any conclusions ?
Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE
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Re: My PST CaK mod.
Walter, thank you very much for your investigation. It helps a lot.swisswalter wrote:Hi Valery
i found the following:
Walter K-line Valery EO 393nm instead of K-line
--------------------------------------------------------------------------------------------------------------------------------------------------
light green bright 1. #1 + #2 light green bright
no go dark 2. #1 + #2 + K-line extremely dark violet. Barely detectable, on the limit of perception
violett 3. #1 + K-line bright pale sand with delicate pinkish hue
green bright 4. #1 + half of K-line
violett 5. K-line alone bright pale sand with pinkish hue
green very bright 6. K-line half
violett, bright 7. #2 alone dark blue and the sky around the sun is deep violet
dark violett 8. #2 + K-line dark violet
dark violett 9. #2 + half K-line
---------------------------------------------------------------------------------------------------------------------------------------------------
My conclusions are:
1. Edmund Optics 394nm has too much (for human eye) leak across the spectrum from violet to red.
2. EO 394nm filter leak averaged is about OD 5
3. if a combination #1 + half K-line does work at short exposures, then a combo #1 + EO 394nm will work about as good.
4. #1 + #2 + EO 394nm will work, but how good - I don't know, possibly at exposures at the level of 1/100 sec for F/10
Walter, may I kindly ask you to perform the final part of experiment?
The experiment is to see how the following combinations work for imaging
1) #1 + 1/2 K-line
2) #1 + #2 + 1/2 K-line ?
Images fo disk and prominences (if they will be seen in general).
Thank you in advance.
Valery.
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Re: My PST CaK mod.
Hi Valery
I'll give it a go and will Report. #1+1/2 K-line will be much too bright I will have to dim it down, mabe with a ND3 after the hot mirror
I'll give it a go and will Report. #1+1/2 K-line will be much too bright I will have to dim it down, mabe with a ND3 after the hot mirror
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Re: My PST CaK mod.
Thanks in advance, Walter.swisswalter wrote:Hi Valery
I'll give it a go and will Report. #1+1/2 K-line will be much too bright I will have to dim it down, mabe with a ND3 after the hot mirror
Do you have ND filters or do you have Hershel prism?
BTW. I do plan to use #1+EO 394nm with ERF filter like Schott BG12.
Valery.
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Re: My PST CaK mod.
To be honest, I think that I am a bit exaggerated the problem. Edmund Optics warranted that all wave lengths out of 10nm bandpass are attenuated with optical density OD>4. In fact the OD is about 5 with very few narrow peaks reached OD4. OD4 means light attenuation in 10.000x !
Even if the CaK PST filter #1 has only 10% transmission at 393,4nm, then S/N will be at least 1000. And this is only for these few peaks. For all other wave lengths the ratio will be about 10.000x.
If I will imaging with 8 bit, then I will not see the filter's leakage at all. Even imaging with 16 bit (really expanded from 12 to 16 bit) I will see only a trace of this leakage.
Even if the CaK PST filter #1 has only 10% transmission at 393,4nm, then S/N will be at least 1000. And this is only for these few peaks. For all other wave lengths the ratio will be about 10.000x.
If I will imaging with 8 bit, then I will not see the filter's leakage at all. Even imaging with 16 bit (really expanded from 12 to 16 bit) I will see only a trace of this leakage.
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Re: My PST CaK mod.
Hi Valery
thank you for your question. I have both, ND filters and Herschel wedges. #1+ 1/2 K-line works not, some sort of WL Image. #1+#2+1/2 K-line works very fine. Pics will follow
thank you for your question. I have both, ND filters and Herschel wedges. #1+ 1/2 K-line works not, some sort of WL Image. #1+#2+1/2 K-line works very fine. Pics will follow
Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE
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Re: My PST CaK mod.
If you still at the telescope, can you add #1 + K-line?swisswalter wrote:Hi Valery
thank you for your question. I have both, ND filters and Herschel wedges. #1+ 1/2 K-line works not, some sort of WL Image. #1+#2+1/2 K-line works very fine. Pics will follow
Can you, please, give all information about equipment, exposures, frames stacked etc.
Thanks,
Valery.
Last edited by Valery on Sat Jun 07, 2014 2:48 pm, edited 1 time in total.
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Re: My PST CaK mod.
Hi Valery
I will as far as I can. There are waiting over 80 avis to be stacked and post proprocessed
I will as far as I can. There are waiting over 80 avis to be stacked and post proprocessed
Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE
from 7 am - 7 pm http://www.nanosys.ch
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Re: My PST CaK mod.
A lot of sunny weather in Switzerland?swisswalter wrote:Hi Valery
I will as far as I can. There are waiting over 80 avis to be stacked and post proprocessed
Please, add #1 + K-line too! This will give a full picture of how all these filters work.
Valery
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Re: My PST CaK mod.
Hi Valery
thank you very much. I will for sure. But there is nothing new Mark and I did not do a year ago
thank you very much. I will for sure. But there is nothing new Mark and I did not do a year ago
Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE
from 7 am - 7 pm http://www.nanosys.ch
from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa
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Re: My PST CaK mod.
Today the mechanical machinist gave me all necessary parts to make my first CaK telescope work. This is a 100mm F=1000mm Bresser achromat.
The train will be as follow:
Objective > internal 50mm ERF (two 80A filters) > #2 PST filter > CaK PST #1 filter > Edmund Optics 394nm filter
In a two weeks I will install front mounted EDF filter which blocks all the radiation from 480 to 2000nm
and has steep ball-like curve and 75% transmission at 394nm.
Two 80A filters reject about 80% of unwanted energy and finally the energy density at the PST filters will be about the same as in native CaK PST scope.
Hope, that tomorrow will be a good blue sky like it was today during my Ha hunting for the Sun.
Valery.
The train will be as follow:
Objective > internal 50mm ERF (two 80A filters) > #2 PST filter > CaK PST #1 filter > Edmund Optics 394nm filter
In a two weeks I will install front mounted EDF filter which blocks all the radiation from 480 to 2000nm
and has steep ball-like curve and 75% transmission at 394nm.
Two 80A filters reject about 80% of unwanted energy and finally the energy density at the PST filters will be about the same as in native CaK PST scope.
Hope, that tomorrow will be a good blue sky like it was today during my Ha hunting for the Sun.
Valery.
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.
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Re: My PST CaK mod.
Hi Valery,
My CaK system is very similar: D100mm F900mm Orion (Skywatcher) ED Objective > internal 50mm ERF (Baader Blue CCD filter) > #2 PST filter > CaK PST #1 filter > Baader CaK filter.
Here are some of my better results:
Bob
My CaK system is very similar: D100mm F900mm Orion (Skywatcher) ED Objective > internal 50mm ERF (Baader Blue CCD filter) > #2 PST filter > CaK PST #1 filter > Baader CaK filter.
Here are some of my better results:
Bob
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Re: My PST CaK mod.
Hi Bob
very fine results indeed
very fine results indeed
Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE
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Re: My PST CaK mod.
Top shots there Bob!
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Re: My PST CaK mod.
Thanks Walter and Mark; not up their with the work of Luca and Harald though -- need more aperture and better seeing for that.
Best wishes,
Bob
Best wishes,
Bob
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Re: My PST CaK mod.
Hi Bob,
Thanks for your nice pictures. Today I finalized my CaK scope #1. If tomorrow will be a clear day, I hope to image sun in CaK at 1m and 2,3m focal length.
Telescope now work fine, no astigmatism just not the best correction at 393nm.
My next CaK telescope will be 150mm refractor or C11.
Thanks for your nice pictures. Today I finalized my CaK scope #1. If tomorrow will be a clear day, I hope to image sun in CaK at 1m and 2,3m focal length.
Telescope now work fine, no astigmatism just not the best correction at 393nm.
My next CaK telescope will be 150mm refractor or C11.
"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.
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Re: My PST CaK mod.
I just have minute, K-line blockers (filters) have trouble with leaks in the green. You sometimes get a mismatch in the layers and you get a narrow bandpass that is not blocked by the ITF. Most of the time it's small and sometimes you can use filter glass to cut it out. But I have sent back blockers where the filter glass didn't work. That may be where the turquoise color is coming from.
Mark W.
Mark W.
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Re: My PST CaK mod.
Mark,mdwmark wrote:I just have minute, K-line blockers (filters) have trouble with leaks in the green. You sometimes get a mismatch in the layers and you get a narrow bandpass that is not blocked by the ITF. Most of the time it's small and sometimes you can use filter glass to cut it out. But I have sent back blockers where the filter glass didn't work. That may be where the turquoise color is coming from.
Mark W.
Thanks for this info. But do you mean K-line blockers in general (all blockers for this K-line) or do you mean Baader K-line filters?
As far as I know, five Baader K-line filters work fine for Luca, Andreas Murner, Max Usatov, Walter K. and Mark T. and in this same time my Edmund Optics 394nm has a leak at the green and longer which I see as pale sand color. However, Baader K-line consists two parts (identical ? ). My EO 394nm is a single and it has filtration of other wave lengths at about OD=4-5. The 1/2 of the Baader K-line filter has about the same leak as my EO single. may I suspect that if I have two EO 394nm double staked, I will have other wave lengths filtration on the level OD 8-10 and in such see only the violet which is about 0.9 transmission is a single filter and will be about 0.81 in double stack?
Valery.
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Re: My PST CaK mod.
Finally, June 14 and 15, 2014 my Ca-K telescope was tested and finally adjusted. Now it's train is as follow:
100mm F/10 achromatic objective > internal ERF (double 80A filters by B&W) > 394nm 10nm block filter by Edmund Optics > CaK PST filter #1 (yellowing one) > flip mirror system by Vixen > PGR Flea3 GigE mono camera with ICX445 chip.
First and second light of this scope are here:
http://solarchat.natca.net/viewtopic.php?f=4&t=11904
http://solarchat.natca.net/viewtopic.php?f=4&t=11894
Many thanks to Bob Yoesly, Mark Wagner, Mark Tawnley, Walter Kohch and all others who helped me with advices and discussions.
Without your friendly help, this project will not be finished or even was not started at all.
Valery.
100mm F/10 achromatic objective > internal ERF (double 80A filters by B&W) > 394nm 10nm block filter by Edmund Optics > CaK PST filter #1 (yellowing one) > flip mirror system by Vixen > PGR Flea3 GigE mono camera with ICX445 chip.
First and second light of this scope are here:
http://solarchat.natca.net/viewtopic.php?f=4&t=11904
http://solarchat.natca.net/viewtopic.php?f=4&t=11894
Many thanks to Bob Yoesly, Mark Wagner, Mark Tawnley, Walter Kohch and all others who helped me with advices and discussions.
Without your friendly help, this project will not be finished or even was not started at all.
Valery.
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.
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Re: My PST CaK mod.
It's great news Valery! It's what this forum is all about. Now all you have to do is double stack it
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Re: My PST CaK mod.
No no! Not only the DS! I also need to increase the apertre at least to 6" and then to even larger. Harald's Paleske CaK images inspire me on growth of the aperture.marktownley wrote:It's great news Valery! It's what this forum is all about. Now all you have to do is double stack it
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Re: My PST CaK mod.
I've bought some of the UV polarising material as described by Mark Wagner. I will report back on how I get on with it
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Re: My PST CaK mod.
Hi Valery
wonderful progress
wonderful progress
Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE
from 7 am - 7 pm http://www.nanosys.ch
from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa
from 7 am - 7 pm http://www.nanosys.ch
from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa
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Re: My PST CaK mod.
What will you use them for?marktownley wrote:I've bought some of the UV polarising material as described by Mark Wagner. I will report back on how I get on with it
Valery.
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.
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Re: My PST CaK mod.
Suppressing the reflections / ghosts which will, I am sure, have a positive effect on contrast.Valery wrote:What will you use them for?marktownley wrote:I've bought some of the UV polarising material as described by Mark Wagner. I will report back on how I get on with it
Valery.
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!
Re: My PST CaK mod.
I'm back, The leak in the green is just something I came across over the years. They where with 1nm blockers blocked to the far IR for etalons. The little bandpass in the green where not bright but they where narrow. The main bandpass would be much brighter, so you would loose only a little contrast. But it did change the back ground color. But for my jobs I couldn't have any others but the main bandpass even if it didn't mater.
Mark W.
Mark W.
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Re: My PST CaK mod.
Hi Mark,
Would you mind explaining a bit about the use of wave plates and polarizers to get rid of reflections, and why to use a circular vs. linear polarizer, and a quarter vs. a half wave-plate is utilized? The Wikipedia article -- http://en.wikipedia.org/wiki/Polarizer -- is a little unclear to me at this point. My limited understanding so far is that the wave-plate "retards" or separates the polarization modes, and a polarizer can then better eliminate one of them - one of which is the reflection(s)...?
Thanks,
Bob
Would you mind explaining a bit about the use of wave plates and polarizers to get rid of reflections, and why to use a circular vs. linear polarizer, and a quarter vs. a half wave-plate is utilized? The Wikipedia article -- http://en.wikipedia.org/wiki/Polarizer -- is a little unclear to me at this point. My limited understanding so far is that the wave-plate "retards" or separates the polarization modes, and a polarizer can then better eliminate one of them - one of which is the reflection(s)...?
Thanks,
Bob
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