White light vs H alpha ?

[SAW]

Hi,

I've just got my solar set up which is a WO61 and Lunt wedge, so I can view in white light. Trying to understand the differences between white light and H alpha. I presume I need to be using a H alpha scope to get the colours images ?

I know I can image with my set up but obviously it's only going to give me the white image, correct ? I have a ZWO120MM to try which I normally use for guiding.

If for example I have Lunt LS50THA can I view the sun giving me the colour ?

 

[alanjgreen]

Saw, dont get hung up on the "colour" its just a false colour created by the hydrogen alpha wavelength.

The suns real colour is "white"

What H-alpha gives you is a whole host of surface features & prominences (edge features) that are only visible in the hydrogen alpha wavelength.

White light will show you sun spots & plage (areas of activity) but no more. To see prominences, filaments, flares, flux et al you need to be viewing in h-alpha.

Search for some sun images from Calcium-K wavelength, they are all purple.

Baader make a solar continiuum filter that you can use in white light to add more detail and this will turn the sun a "green" colour.

https://www.firstlightoptics.com/solar-filters/baader-solar-continuum-filter.html

As I say, its not about the colour!

Alan

[John]

I think this image illustrates the differences reasonably well (whilte light on the right). My Lunt LS50 gives me a view similar to the left hand side:

 

[SAW]

I've got one of these https://www.firstlightoptics.com/moon-neutral-density-filters/baader-single-polarising-filter.html but completely forgot to use it and the sun has almost gone now :-(

So H alpha will show me the flares 

[Macavity]

In my simplistic way, I see White Light as a bit like looking at the "surface"
(Photosphere) of the sun and H-Alpha a bit like looking at the "atmosphere"
(Chromosphere) of the sun. CaK & HA show different heights in the latter.

[SAW]

7 minutes ago, alanjgreen said:

Saw, dont get hung up on the "colour" its just a false colour created by the hydrogen alpha wavelength.

The suns real colour is "white"

What H-alpha gives you is a whole host of surface features & prominences (edge features) that are only visible in the hydrogen alpha wavelength.

White light will show you sun spots & plage (areas of activity) but no more. To see prominences, filaments, flares, flux et al you need to be viewing in h-alpha.

Search for some sun images from Calcium-K wavelength, they are all purple.

Baader make a solar continiuum filter that you can use in white light to add more detail and this will turn the sun a "green" colour.

https://www.firstlightoptics.com/solar-filters/baader-solar-continuum-filter.html

As I say, its not about the colour!

Alan

Does that filter help with seeing the flares ? 

Would I also need https://www.firstlightoptics.com/uv-ir-filters/baader-uvir-cut-filter.html if so does it matter what order the two filters are installed ? obviously both after the wedge ! lol

[Ibbo!]

19 minutes ago, SAW said:

Does that filter help with seeing the flares ? 

Would I also need https://www.firstlightoptics.com/uv-ir-filters/baader-uvir-cut-filter.html if so does it matter what order the two filters are installed ? obviously both after the wedge ! lol

No it will not show the flares or the prominences.

 

You need a dedicated ha alpha solar telescope or a Quark.

The bandwidth needs to be very low less than 1 nm coupled with the proper blocking filters.

[SAW]

I best just practice with what I've got for now while I keep saving for my Lunt.

[Ibbo!]

1 minute ago, SAW said:

I best just practice with what I've got for now while I keep saving for my Lunt.

 

Good plan

[DrRobin]

As others have mentioned the colour is false, the difference is what you can see.

White Light (with your wedge) shows sunspots, plage and granulation (on close ups).  WL can be very interesting especially when there are some nice sunspot groups.

Hydrogen Alpha (Lunt or Daystar Quark) looks through the hotter outer layers and shows more surface detail such as filaments, prominences and magnet lines/loops.  In terms of detail the 'most bang for your buck'.

Calcium-K shows different surface detail but is more similar to White Light, only much more detail.

Have a look at my post from today, a full disc in Calcium-K and a small section in Ha (taking with a Quark) showing a filament (dark cloud like structure).

If you want to get a bit more detail in your white light shots you could try a Baader K-line filter screwed in on the end of your camera and after the wedge.  It will add a significant amount of detail to the WL and start to show some of the features shown in the Calcium-K shots.  Shoot in mono and add the false colour later.

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p3415_Baader-stacked-1-25--K-line-filter-for-Solar-photography.html

Robin

[Moonshane]

The red of H alpha (visually at least) is actually red as this is the colour of the wavelength of light to which the sunlight is filtered. The whole light emitted by the sun is white and it is the whole spectrum that comes through the wedge albeit reduced dramatically.

[Moonshane]

The chromosphere (HA) is above the photosphere (white light) so technically you look through the HA detail to see the white light detail. The latter is so bright that it needs to be filtered out to see the 'gossamer' layer of HA above it.

[Stu]

Great posts Shane  

[Moonshane]

I seem to post better quality content during my frantic Uni assignment writing phases as I am in the 'evidencing zone'. 

[Peter Drew]

4 hours ago, Macavity said:

In my simplistic way, I see White Light as a bit like looking at the "surface"
(Photosphere) of the sun and H-Alpha a bit like looking at the "atmosphere"
(Chromosphere) of the sun. CaK & HA show different heights in the latter.

Spot on! (or not depending on the cycle) 

[SAW]

On 07/01/2018 at 15:28, John said:

I think this image illustrates the differences reasonably well (whilte light on the right). My Lunt LS50 gives me a view similar to the left hand side:

 

Have you added the colour in that white light image on the right ?

[Lowjiber]

You've gotten a ton of solid advice above, and I can't add anything more regarding WL verses Ha.

However, having helped a lot of new solar imagers get started, I sense that adding color is getting in your way.  So, let me make a comment in that direction...

Yes, John "added color" to both the left & right of the image above.  We capture the sun (WL or Ha) with monochrome cams for one reason... a monochrome cam has four times as many pixels capturing details than a color cam of the same size.

The resulting image is very detailed, but is devoid of color.  We add color (to our taste) using something like Photoshop, GIMP, etc.  That last "hurdle" often seems daunting to some who haven't used the tool... Yet.  Let me assure you that it is not difficult at all.

Below is a very simple demonstration to prove my point.  I opened a so-so image of the moon that was captured with a monochrome cam; stacked in AS2; and tweaked with Registax.  I then "threw" it into Photoshop and with three left-clicks had the image "colored".  No muss, no fuss.

I encourage you not to let the "coloring" issue stop you from learning to capture the sun.  It is not a big deal in any way-manner-shape-or-form.

Clear Skies

 

[Pete Presland]

For quite a while I never bothered to colour my Solar images at all, these I do. I am still not convinced it adds much to them to be honest