Solar Continuum Filter

Use this section to discuss "standard" Baader/Coronado/ Lunt SolarView/ Daystar, etc… filters, cameras and scopes. No mods, just questions/ answers and reviews.
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alessbonsai
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Solar Continuum Filter

Post by alessbonsai »

Why is a Solar Continuum Filter and not a Ha filter used in WL?


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Re: Solar Continuum Filter

Post by Simon2940 »

Because you are looking at the photosphere, not the chromosphere.

The green colored filter is narrowing down to 540nm in wavelength. This basically results in the edges of where the cracked glass appearance higher in contrast.
132460279_1328872917473228_6750710028564337352_n.jpg
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Re: Solar Continuum Filter

Post by Bob Yoesle »

You could use an H alpha filter (and many others) for WL continuum (photosphere) use as well. Either an off-band narrow (less than 0.1 nm) filter that is used for observation the chomosphere emission at 656 nm, or a much wider band ( 7 - 32 nm) nighttime H alpha filter could be used with a Herschel wedge, solar film, etc.

The Baader Continuum filter is specifically made to peak at 540 nm, as most telescopes are designed to provide their best visual performance and optical correction at that wavelength. This generally will give you very good contrast to best see sunspots, solar granulation, etc. of the photosphere.

The narrower H alpha and CaK filters are meant to see deeply into the the photosphere absorption line(s), where you will than see the emission line features of the chromosphere.

The Sun MTMinc LR enhncd SM.jpg
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Re: Solar Continuum Filter

Post by christian viladrich »

As explained by Bob, you can take any filter to observe/image the photosphere.
As a general rule :
- the contrast of granulation increases when going to the blue end of the spectrum,
- turbulence increases when going to the blue end of the spectrum,
- some refractors have a lower optical quality in the blue,
- eye max sensitivity and vision of contrast is in the green.


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Re: Solar Continuum Filter

Post by alessbonsai »

now I have clearer ideas


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Re: Solar Continuum Filter

Post by rsfoto »

Bob Yoesle wrote: Thu Feb 25, 2021 7:48 pm You could use an H alpha filter (and many others) for WL continuum (photosphere) use as well. Either an off-band narrow (less than 0.1 nm) filter that is used for observation the chomosphere emission at 656 nm, or a much wider band ( 7 - 32 nm) nighttime H alpha filter could be used with a Herschel wedge, solar film, etc.

The Baader Continuum filter is specifically made to peak at 540 nm, as most telescopes are designed to provide their best visual performance and optical correction at that wavelength. This generally will give you very good contrast to best see sunspots, solar granulation, etc. of the photosphere.

The narrower H alpha and CaK filters are meant to see deeply into the the photosphere absorption line(s), where you will than see the emission line features of the chromosphere.


The Sun MTMinc LR enhncd SM.jpg
Hi Bob,

Thank you very much for that image and explanation. Now I ask about the spicules and are these the transition zone NASA speaks about here ?

https://www.nasa.gov/mission_pages/iris ... erzoo.html

:bow2


regards Rainer

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Re: Solar Continuum Filter

Post by DeepSolar64 »

I use the 540nm filter a lot. It's a major part of my arsenal on studying the photosphere.


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