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Solar Viewing Question?

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#1 sg6

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Posted 07 July 2020 - 01:15 PM

OK, Likely to cause arguements but after a few years I just need to ask.

When people buy a film front filter many expect to see solar surface structure in the form of granularity and also flares bursting forth from the edge of the sun.

 

I am one of the first to point out they should not expect such detail.

 

So the question:

What makes a solar scope, say Ha, a solar scope that displays surface granularity and flares?

 

Why is it not apparently possible to add items in to a "standard" scope to do so? Say a front filter and assorted bits between rear of scope and eyepiece.

 

We have polarizers, linear and circular, Herschel wedges, some that are at the Brewster angle so deliver polarized light, we have assorted narrow band filters - many at Ha.

 

My Herschel wedge has the wedge to drop to 5%, then an ND3 filter, a continium filter and a UV+IR cut filter. So adding filters would seem fairly "easy".

 

Just one of those questions of Why? or Why not?

Suppose it is basically: With an everyday scope, refractor. Could you add standard off the shelf items to get to a "proper" solar scope that displays surface detail and flares?

 

As said I/we keep saying you cannot see surface and flare detail but why can you not by some hopefully simple method. One day some one will reply to me saying "You cannot" and ask "Why can I not somehow?". And basically I don't know.


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#2 Astrojensen

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Posted 07 July 2020 - 01:24 PM

 

With an everyday scope, refractor. Could you add standard off the shelf items to get to a "proper" solar scope that displays surface detail and flares?

YES! It's called a Daystar Quark. Just this and a UV/IR filter in front of your diagonal and you're good to go. It shows the Sun in glorious H-alpha details. 

 

https://daystarfilters.com/

 

http://www.daystarfi...com/Quark.shtml

 

I use one myself on a range of refractors, including a 63/840mm, 72/430mm, 80/1200mm, 102/1122mm and 152/1200mm. In all cases it delivers outstanding performance that in most cases have been not only as good, but BETTER than most dedicated solar scopes I've seen. 

 

There are other systems available, including from Daystar, but they're vastly more expensive.

 

 

Clear skies!
Thomas, Denmark


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#3 Astrojensen

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Posted 07 July 2020 - 01:30 PM

Here it's shown set up on my Zeiss C63/840 Telemator. It's the bulky unit between the diagonal and the binoviewer. The 63mm Zeiss is small enough that a UV/IR filter isn't needed. There's a built-in barlow inside the Quark, so the binoviewer comes to focus easily! 

 

gallery_55742_4772_130798.jpg

 

 

Clear skies!
Thomas, Denmark



#4 NorthernlatAK

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Posted 07 July 2020 - 02:01 PM

Here's a quark on my 102mm f9.8 refractor for ha and my 8" dob with homemade baader film filter for wl. The quark just goes in the focuser and a uv/ir blocking filter before the diagonal. The quark shows prominences, filaments, spicules, plages, in a red color visually. The dob shows sunspots and convection cells in whitelight.

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#5 TOMDEY

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Posted 07 July 2020 - 02:37 PM

The reason a sub-angstrom etalon filter is needed is that the overwhelming black body radiation of the sun is competing. This reduces the contrast of the H-Alpha... essentially to invisibility once the bandwidth gets around two angstroms. That's really all there is to it. And the half-angstrom filters are difficult to make, and therefore expensive.    Tom



#6 MalVeauX

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Posted 07 July 2020 - 03:05 PM



 

Why is it not apparently possible to add items in to a "standard" scope to do so? Say a front filter and assorted bits between rear of scope and eyepiece.

 

Just one of those questions of Why? or Why not?

Suppose it is basically: With an everyday scope, refractor. Could you add standard off the shelf items to get to a "proper" solar scope that displays surface detail and flares?

Heya,

 

You can add a filter to just about any scope out there. They've been around for many decades now.

 

It's just always going to be expensive to do so. No free lunch. Photosphere solar viewing (white light often termed) can be done inexpensively. But to view the chromosphere, it costs money.

 

Wanna put a filter on the front of the scope? Front mounted HA filters are available from Lunt/Coronado.

Solarmax Series

 

Here's a pair of Solarmax 60mm HA filters front mounted on my ED80 refractor for example:

 

49953599283_689959d9ff_z.jpg

 

Wanna put a filter on the back of a scope? Rear mounted HA filters are available from Daystar and SolarSpectrum.

Daystar Quark

 

Here's a Daystar Quark HA filter rear mounted on my Omni XLT 120mm refractor for example:

 

32728257036_4571d79fb9_z.jpg

 

You can easily put these onto refractors with minimal to no additional energy rejection depending on the size of the refractor. Makes it very plug-n-play. Can use front or rear mounted HA filters.

Other optical designs like newtonian, SCT, Mak, etc, need energy rejection filtration involved. These mostly use rear mounted HA filters.

 

Flares can be seen in multiple wavelengths, not unique to HA. But flares and prominences are not the same thing. Also, granulation (convection cells make this up) and granularity and the chromosphere network and mottling are not the same thing.

 

Why: The chromosphere is incredibly dim compared to the incredibly bright photosphere that is underneath the chromosphere. So no matter what you're trying to accomplish, if you want to see chromosphere structures, we have to block the light of the photosphere from swamping out the surface brightness of the chromosphere, which means we need to block it all basically down to 656.28nm. You don't need sub-angstrom to do this, about 1A is all it takes in reality. An etalon is just an affordable way to 1A or sub-angstrom bandpass. It's possible to do it without an etalon, but creating hard coated 1A bandpass filters with high transmission is even more difficult to create than a good etalon is. So naturally the entire industry uses etalons for HA for this purpose.

 

Very best,


Edited by MalVeauX, 07 July 2020 - 04:08 PM.

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#7 Don W

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Posted 07 July 2020 - 03:19 PM

A note on terminology. Many people refer to prominences as flares. They are not the same thing.


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#8 BYoesle

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Posted 07 July 2020 - 06:14 PM

Sounds like there's a need for more understanding about solar structure and what you can see, and the appropriate nomenclature. For example, the difference between the photosphere and the chromosphere and their features.

 

Sun_poster.svg_.png

 

Here's a good basic description of these structures.

 

Here's a great book about the Sun and solar observing and equipment.

 

As to why you can't use a white light filter designed for viewing the photosphere to see features of the chromosphere, see the posts here and here.


Edited by BYoesle, 07 July 2020 - 08:14 PM.

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#9 bigdob24

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Posted 07 July 2020 - 07:00 PM

I second the book.

An excellent source of information, I thumb through mine a lot 


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