Hydrogen Beta Solar Astronomy Filters

Frankenscope? Let's see it!***be advised that NOTHING in this forum has been safety tested and you are reading and using these posts at your own peril. blah, blah, blah... dont mess around with your eyesight when it comes to solar astronomy. Use appropriate filtration at all times...
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Hydrogen Beta Solar Astronomy Filters

Post by marktownley »

Could be interesting...

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Re: Hydrogen Beta Solar Astronomy Filters

Post by markthais »

10 Ang, This is what I would use as the blocker. My concern would be that the ITF is cemented to the bandpass. This would be the standard design. You will probably end up having secondary reflections. If this is not a problem then you would need an etalon with a peak at Hbeta. 10 ang would be way to broad for H beta images.


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Re: Hydrogen Beta Solar Astronomy Filters

Post by marktownley »

Thanks for that Mark, useful information :)


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Re: Hydrogen Beta Solar Astronomy Filters

Post by colinsk »

10 Ang, This is what I would use as the blocker. My concern would be that the ITF is cemented to the bandpass. This would be the standard design. You will probably end up having secondary reflections. If this is not a problem then you would need an etalon with a peak at Hbeta. 10 ang would be way to broad for H beta images.

What is the width of H-Beta?


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Re: Hydrogen Beta Solar Astronomy Filters

Post by Spectral Joe »

Just a shade narrower than H alpha.





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Re: Hydrogen Beta Solar Astronomy Filters

Post by markthais »

Back in the old days when film was new H beta was the line of H to shoot at. The old films were not sensitive that far in the red for Ha. We didn't have a good 35mm film till SO-410 came out in the 70's to shoot Ha with.This was a B&W film. In color, slide film could pick up the prominences but didn't have the contrast for the disk. A different world from how they image now.
What would you use an H beta for? I was told that H beta does well on filaments.
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Re: Hydrogen Beta Solar Astronomy Filters

Post by Merlin66 »

Based on the electron shells and energy levels the Hbeta emmission/ absorption has a direct relationship with Ha, about 50% the line strength.
What is visible in Ha would appear at 50% intensity in Hbeta.


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Re: Hydrogen Beta Solar Astronomy Filters

Post by sullij1 »

Regardining what Markthais said, then this would be a "blocker" in a Ha scope?????????


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Re: Hydrogen Beta Solar Astronomy Filters

Post by Merlin66 »

No, It would be a "blocker" in a H beta scope.....


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Re: Hydrogen Beta Solar Astronomy Filters

Post by sullij1 »

Ahh, ok makes sense, aka Groski prom viewer.

http://www.considine.net/dgroski/promscope/

Using the filters Mark linked to. Or the .5 nm pair Omega bob advertises here:

http://www.ebay.com/itm/Optical-Interfe ... 484b2bd1cb

Correct?


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Re: Hydrogen Beta Solar Astronomy Filters

Post by marktownley »

I will not be buying any of these H-beta filters unless I also come across (at a cheap price) an etalon that is tuned for H-Beta...


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Re: Hydrogen Beta Solar Astronomy Filters

Post by sullij1 »

Also, Smie develpoed a product based on the same idea here:
http://en.beloptik.de/prominence_viewer.html
All this built on the ideas revolving around the ideas of Marcello Lugli
"Years" earlier? Although Dr. Lugi based his device on the Ha bandpass the idea is still the same, correct?
http://digilander.libero.it/malug/Inglese/Eclissun.htm


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Re: Hydrogen Beta Solar Astronomy Filters

Post by sullij1 »

Mark,

As I understand it, basically these filters are modern etalons, essentially etalons tuned to the bandpass using thin film deposition process instead of mica etalons. But the theory remains the same, light is reflected and narrowed using interference reflection as presented in this white paper by Melles Groit. Here:

https://www.cvimellesgriot.com/products ... l_Note.pdf

As I understand it (the company I work for dabbles in this) an etalon is nothing more than a Fabry-Perot interferometer that can be closly duplicated by thin film deposition. So the filters (or at least one of them as in Omega Bob's Ha pass) are basically etalons tuned to the appropriate band pass using this technology.

Feel free to correct me if wrong.


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Re: Hydrogen Beta Solar Astronomy Filters

Post by sullij1 »

Often Dr. Johnsons (Dr. Robert (Omega Bob) Johnson) filters are more sophisticated than some people give him credit for.


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Re: Hydrogen Beta Solar Astronomy Filters

Post by colinbm »

Hi Joe
Check your yahoo mail
Col


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Re: Hydrogen Beta Solar Astronomy Filters

Post by DavidG »

Ahh, ok makes sense, aka Groski prom viewer.

http://www.considine.net/dgroski/promscope/

Using the filters Mark linked to. Or the .5 nm pair Omega bob advertises here:

http://www.ebay.com/itm/Optical-Interfe ... 484b2bd1cb

Correct?


One of people that has built my coronagraph design ie promoscope, that posts regularly on Cloudy Nights whose tag is 'HighFnum' was also interested in this filter and purchased one and tried it. He reported to me just a few days ago that he was able to see proms at the H-beta wavelength but as I told him the the contrast be low and he confirmed this. The Omega filter has many side bands. I sugguested that a better approach would be to used narrow band filter designed for an Argon Laser at 488nm and tilt it to tune it for 486.1nm. The band pass will widen some but when used in a coronagraph that is properly constructed the loss of contrast won't be too bad.

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Re: Hydrogen Beta Solar Astronomy Filters

Post by sullij1 »

Personally, I feel that if you have an Ha scope you would not need one of these. Why not just do the old high exposure Ha prom shot and occult the overexposed disk in photo shop. I suppose if you are a visual guy this would be trick. But even simple a PST resolves proms well. So why????


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Re: Hydrogen Beta Solar Astronomy Filters

Post by DavidG »

Personally, I feel that if you have an Ha scope you would not need one of these. Why not just do the old high exposure Ha prom shot and occult the overexposed disk in photo shop. I suppose if you are a visual guy this would be trick. But even simple a PST resolves proms well. So why????

Just as the surface of the Sun looks different in Ha,Hb,Na, He-D, CaK and CaH, so do the proms at different wavelengths. One gets both Doppler shift and compositional information froms views at various wavelengths.
A coronagraph greatly reduces stray light which increases signal to noise and allows wider band filters to show proms. Without the reduction in stray light, you won't be able to image the proms because contrast will be too low with these wider band filters. Also wider band filters are not effect as much by Doppler shifting so if a proms is moving very quickly one can see all of it at one time.

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Re: Hydrogen Beta Solar Astronomy Filters

Post by sullij1 »

Thanks. :)

Happy Holidays to all.


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Re: Hydrogen Beta Solar Astronomy Filters

Post by brianb11213 »

Based on the electron shells and energy levels the Hbeta emmission/ absorption has a direct relationship with Ha, about 50% the line strength.
What is visible in Ha would appear at 50% intensity in Hbeta.
Indeed - anything which would appear dark by Hb absorbtion would also appear dark in Ha, and anything which would appear bright by Hb emission would also appear bright in Ha. There may be a very slight bias to Hb relative to Ha at higher temperatures but I think this would be offset by the narrower line width of Hb (in proportion to the working wavelength).

Hb makes sense for visual observation of hydrogen emission nebulae because the dark adapted eye is much more sensitive to the green / blue wavelength of Hb than it is to the deep red of Ha. Silicon based sensors don't have that problem, and lack of light is not much of an issue for visual observing in Ha ... meanwhile the longer wavelength of Ha has its benefits in terms of steadier seeing.

If you're looking for a different narrow band solar filter, why not try the Daystar sodium unit? (Does anyone have experience of this?)

Incidentally, has anyone tried inserting an occulting disk in a Ha solar scope to see if it improves the contrast in the proms? I have a feeling that the huge complexity of the etalon / blocking filter combination is such that there would simply be too much scatter to make the occulting disk effective ... overexposure of the (unblocked, but heavily filtered) solar disk doesn't affect the visibility of the fainter proms in the way that excess scatter does.


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Re: Hydrogen Beta Solar Astronomy Filters

Post by DavidG »

Incidentally, has anyone tried inserting an occulting disk in a Ha solar scope to see if it improves the contrast in the proms? I have a feeling that the huge complexity of the etalon / blocking filter combination is such that there would simply be too much scatter to make the occulting disk effective ... overexposure of the (unblocked, but heavily filtered) solar disk doesn't affect the visibility of the fainter proms in the way that excess scatter does.

A simple occulting disk may not do much. What you need to do is remove scattered light. The way a coronagraph works is the image is focused on the occulting disk and relay optics are also focused on it. An aperture stop is used to remove the scatter light from the system. A simple way to do is to make occulting eyepiece. A Kellner eyepiece is perfect for this. You would glue a stud to the field lens and it's length would need to be set so the edge of the occulting disk is in sharp focus in the eyepiece, then the telescope is focused on the occulted disk as well. The size of the occulting disk to block the disk of the Sun would be 0.0092 x fl of the scope.
One could also punch out a disk from say Baader solar film and attach to the center of clear eyepiece filter and screw the filter into a Kellner eyepiece until the edge of the disk is in focus and then use it with H-alpha or CaK scope to improve the contrast of proms.

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Re: Hydrogen Beta Solar Astronomy Filters

Post by swisswalter »

Hi David

thank you for that information, very interesting


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Re: Hydrogen Beta Solar Astronomy Filters

Post by highfnum »

hello davidg, swisswalter it highfnum from cloudy nights
I joined up after david pointed me to this site

yea I purchsed 0.5nm pair used a spectroscope to help tune it
then I placed in SPV

I was thrilled to see prom in h-beta
contrast was low not as good as 10A h-alpha
but I also chose worst time of year (sun low , lots of bad weather)
im hopeing to get a shot at some point to prove.
spv is a better visual tool than photo since occulting disk
gets in way of small chips


do you guys know work that walter j semerau did with cornascopes and spectroscopes
back in 50's?


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Re: Hydrogen Beta Solar Astronomy Filters

Post by swisswalter »

Hi John

welcome to that wonderful TOS free site. Have sun, have fun


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: Hydrogen Beta Solar Astronomy Filters

Post by sullij1 »

Yes, welcome.


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Re: Hydrogen Beta Solar Astronomy Filters

Post by highfnum »

to begin here is my spectroscope image of h-beta line

Attached files


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Re: Hydrogen Beta Solar Astronomy Filters

Post by swisswalter »

Hi John

what a fine spectrum


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Re: Hydrogen Beta Solar Astronomy Filters

Post by sullij1 »

Gee, thread died. John, U got imagery?


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Re: Hydrogen Beta Solar Astronomy Filters

Post by highfnum »

had rig set up this morn - clouds roll in- eug
:evil:
im just frustrated with weather
believe me one look isnt enough !


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Re: Hydrogen Beta Solar Astronomy Filters

Post by highfnum »

finally got to do some testing with h-beta filter

good and bad news

1) good news is - I got to see some more proms with h-beta filter and david G spv

2) the bad new is that filter has a sweet spot I could see them on on side but
not the other
sky was clear late so I only got about 20 minutes of testing
i will try to rotae filter to see if I can view on oposite side

3) I got orion smart phone holder as a holiday gift maybe I can shoot a photo
I know commumity wants proof


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Re: Hydrogen Beta Solar Astronomy Filters

Post by swisswalter »

Hi John

still good news. Looking forward to your pics


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Re: Hydrogen Beta Solar Astronomy Filters

Post by highfnum »

did some more viewing
it so cool to see proms in h-beta
again thank you DavidG for making this possible
(it all started when I asked him what became of criterion SPV)


taking pic is going to be tricky

as ypu know SPV works by blocking out disk
slightest vibs can destroy image contrast as disk "pops out"

5 A h-beta is much more sensitive than 10A h-alpha filter a 2A filter would be better

h-beta has less contrast - anything like sky haze kills it pronto

if you cant see it in h-alpha you will not see it in h-beta period

if you have excellent signal in h-alpha then you have a chance in h-beta

i had to open iris more that h-alpha which is counter intuitive to me

none the less I'm happy cant wait for more sun time

I understand that very few ATM'ers have ever done this


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