How do you study and observe granulation in H Alpha?

this is the main message area for anything solar :)
Post Reply
Solarscout
Ohhhhhh My!
Ohhhhhh My!
Posts: 61
Joined: Tue May 23, 2023 6:55 am
Has thanked: 9 times
Been thanked: 91 times

How do you study and observe granulation in H Alpha?

Post by Solarscout »

Apparently in H alpha granulation shows up more as a mottled surface of dark and bright patches. I tried to observe granular cells in white light but not able to see anything


User avatar
rigel123
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 8114
Joined: Thu Apr 08, 2021 9:26 pm
Location: Mason, OH
Has thanked: 9373 times
Been thanked: 9590 times
Contact:

Re: How do you study and observe granulation in H Alpha?

Post by rigel123 »

Granulation is seen in the Photosphere and will not be seen in Ha. You need good seeing along with enough resolution to study the granular cells. The mottled surface you see in Ha are the spicules in the chromosphere.

I suggest you start out with this book as many of the questions you ask can easily be answered in this great little guide:

https://www.amazon.com/Observing-Sun-Po ... 101&sr=8-5


Warren

Lunt LS60T DS
Orion ED80T CF
Meade ETX LS6
Lunt CaK BF1200
Lunt WL Wedge
Baader Photographic Film
ASI174MM
Skyris 236M
Player One Saturn-M SQR

https://www.astrobin.com/users/rigel123/
Solarscout
Ohhhhhh My!
Ohhhhhh My!
Posts: 61
Joined: Tue May 23, 2023 6:55 am
Has thanked: 9 times
Been thanked: 91 times

Re: How do you study and observe granulation in H Alpha?

Post by Solarscout »

Thanks. I read this page which said that granulation is visible in H Alpha?

"Granulation - the mottled appearance of the solar disk as seen in Hydrogen Alpha. It will appear as bright patches separated by darker boundaries. Granulation is an illustration of convection in the Sun, the process by which heat flows from the interior to the surface of the Sun. When you are looking at the granules, you are looking at hot blobs of matter that are rising to the surface of the Sun from the even hotter interior, cooling off, then sinking back into the interior again. Since granulation is the process by which heat flows from the center of the Sun to its exterior, it is present even at solar minimum."


Dennis
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 1937
Joined: Sat Apr 27, 2019 6:44 pm
Location: Germany
Has thanked: 3434 times
Been thanked: 2528 times

Re: How do you study and observe granulation in H Alpha?

Post by Dennis »

Solarscout wrote: Mon Aug 14, 2023 5:25 pm Thanks. I read this page which said that granulation is visible in H Alpha?

"Granulation - the mottled appearance of the solar disk as seen in Hydrogen Alpha. It will appear as bright patches separated by darker boundaries. Granulation is an illustration of convection in the Sun, the process by which heat flows from the interior to the surface of the Sun. When you are looking at the granules, you are looking at hot blobs of matter that are rising to the surface of the Sun from the even hotter interior, cooling off, then sinking back into the interior again. Since granulation is the process by which heat flows from the center of the Sun to its exterior, it is present even at solar minimum."

I was stumbeling over this too some time ago. The part about the granulation is wrong. It is not related to the image shown nor to h-alpha in general.
Also the other images appear to be extremely low in resolution / quality, maybe from early days of h-alpha filters.

Solar granulation is visible with wl-filters (photosphere). The term "h-alpha" i connect with narrow band filters.


Triband C9.25

H-a: 2x Lunt40 rear mounted

WL: Antlia 500nm/ 3nm, 393 nm/ 3nm

Ca-K: homebrew (includes 2x 1.5A filters, thanks Apollo), corrective lenses (thanks again Apollo)

Cameras: imx432 + imx462
Barlows:
-2x Gerd Düring 2.7x
-2x TMB 1.8x
User avatar
rigel123
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 8114
Joined: Thu Apr 08, 2021 9:26 pm
Location: Mason, OH
Has thanked: 9373 times
Been thanked: 9590 times
Contact:

Re: How do you study and observe granulation in H Alpha?

Post by rigel123 »

Solarscout wrote: Mon Aug 14, 2023 5:25 pm Thanks. I read this page which said that granulation is visible in H Alpha?

"Granulation - the mottled appearance of the solar disk as seen in Hydrogen Alpha. It will appear as bright patches separated by darker boundaries. Granulation is an illustration of convection in the Sun, the process by which heat flows from the interior to the surface of the Sun. When you are looking at the granules, you are looking at hot blobs of matter that are rising to the surface of the Sun from the even hotter interior, cooling off, then sinking back into the interior again. Since granulation is the process by which heat flows from the center of the Sun to its exterior, it is present even at solar minimum."
Where was this quote? In Jamey's guide on pages 24 - 26 the granulation is clearly described as a Photospheric phenomenon only. The mottled appearance of the chromosphere comes from spicules.


Warren

Lunt LS60T DS
Orion ED80T CF
Meade ETX LS6
Lunt CaK BF1200
Lunt WL Wedge
Baader Photographic Film
ASI174MM
Skyris 236M
Player One Saturn-M SQR

https://www.astrobin.com/users/rigel123/
Dennis
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 1937
Joined: Sat Apr 27, 2019 6:44 pm
Location: Germany
Has thanked: 3434 times
Been thanked: 2528 times

Re: How do you study and observe granulation in H Alpha?

Post by Dennis »

rigel123 wrote: Mon Aug 14, 2023 7:26 pm
Solarscout wrote: Mon Aug 14, 2023 5:25 pm Thanks. I read this page which said that granulation is visible in H Alpha?

"Granulation - the mottled appearance of the solar disk as seen in Hydrogen Alpha. It will appear as bright patches separated by darker boundaries. Granulation is an illustration of convection in the Sun, the process by which heat flows from the interior to the surface of the Sun. When you are looking at the granules, you are looking at hot blobs of matter that are rising to the surface of the Sun from the even hotter interior, cooling off, then sinking back into the interior again. Since granulation is the process by which heat flows from the center of the Sun to its exterior, it is present even at solar minimum."
Where was this quote? In Jamey's guide on pages 24 - 26 the granulation is clearly described as a Photospheric phenomenon only. The mottled appearance of the chromosphere comes from spicules.

https://itu.physics.uiowa.edu/labs/obse ... atures-sun


Triband C9.25

H-a: 2x Lunt40 rear mounted

WL: Antlia 500nm/ 3nm, 393 nm/ 3nm

Ca-K: homebrew (includes 2x 1.5A filters, thanks Apollo), corrective lenses (thanks again Apollo)

Cameras: imx432 + imx462
Barlows:
-2x Gerd Düring 2.7x
-2x TMB 1.8x
User avatar
rigel123
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 8114
Joined: Thu Apr 08, 2021 9:26 pm
Location: Mason, OH
Has thanked: 9373 times
Been thanked: 9590 times
Contact:

Re: How do you study and observe granulation in H Alpha?

Post by rigel123 »

Whoever wrote that report must have read something wrong in whatever sources they utilized.


Warren

Lunt LS60T DS
Orion ED80T CF
Meade ETX LS6
Lunt CaK BF1200
Lunt WL Wedge
Baader Photographic Film
ASI174MM
Skyris 236M
Player One Saturn-M SQR

https://www.astrobin.com/users/rigel123/
User avatar
DeepSolar64
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 19719
Joined: Thu Sep 05, 2019 12:19 am
Location: Lowndesville S.C.
Has thanked: 18637 times
Been thanked: 17784 times

Re: How do you study and observe granulation in H Alpha?

Post by DeepSolar64 »

The granulation seen in the chromosphere are known as " the mottles ". They are basically spicule clusters that cover the chromosphere of the sun like fur on a cat. Visually they appear as a mottling of the chromosphere and are hard to resolve by eye. Imaging however reveals their true nature and they show up really well in inverted images resolving the spicules themselves, especially with larger apertures. The white light photosphere granulation appears as a fine texturing of the photosphere visually and the individual granules that make up the texturing are quite small, 1.5" or smaller. They are difficult visually but show up very well in images through 6" and larger apertures. These granules are the convection cells of the photosphere.

James


Lunt 8x32 SUNoculars
Orion 70mm Solar Telescope
Celestron AstroMaster Alt/Az Mount
Meade Coronado SolarMax II 60 DS
Meade Coronado SolarMax II 90 DS
Meade Coronado AZS Alt/Az Mount
Astro-Tech AT72EDII with Altair solar wedge
Celestron NexStar 102GT with Altair solar wedge
Losmandy AZ8 Alt/Az Mount
Sky-Watcher AZGTI Alt-Az GoTo mount
Cameras: ZWO ASI178MM, PGR Grasshopper, PGR Flea
Lunt, Coronado, TeleVue, Orion and Meade eyepieces

Image Visual Observer
" Way more fun to see it! "
christian viladrich
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 2219
Joined: Sun Jun 14, 2015 4:46 pm
Location: France
Has thanked: 1 time
Been thanked: 2816 times
Contact:

Re: How do you study and observe granulation in H Alpha?

Post by christian viladrich »

DeepSolar64 wrote: Tue Aug 15, 2023 4:43 am The granulation seen in the chromosphere are known as " the mottles "
There is no granulation in the chromosphere. As said above, granulation refers to the convection cells visible in the photosphere. The interior of the cell is bright while its frontier is dark.
http://astrosurf.com/viladrich/astro/so ... 0-OIII.jpg

In the lower heights of chromosphere (visible in Ca K or H) , reverse granulation is visible : the interior of the convection cell is dark, while the frontier of the cell is bright.
http://astrosurf.com/viladrich/astro/so ... -014nm.jpg

Higher the the chromosphere (visible in Ha), there is no granulation visible at all. Convection does not reach so high.


Christian Viladrich
Co-author of "Planetary Astronomy"
http://planetary-astronomy.com/
Editor of "Solar Astronomy"
http://www.astronomiesolaire.com/
Post Reply