20221026 10H21 TU CORONOGRAPHE W LILLE WEB.jpg

Very nice pic, very clear, focused.  Thanks!

WnA

Wow, I didn’t know you could do coronagraph images from the ground!

On 10/26/2022 at 4:03 PM, Orneno said:

Wow, I didn’t know you could do coronagraph images from the ground!

Howdy Orneno,

This isn’t a coronagraph - at least not one like you are used to seeing on LASCO. It’s just a nice H-alpha image. The sun has probably been blacked out in post processing the image. Here, you’re looking at features from the chromosphere and transition zone.  
 

You can see a number of H-alpha images on gong. They are pretty cool. I just got an H-a filter a couple of months ago, and this is the kind of thing that becomes visible…. I’m looking forward t getting my cameras connected. 
 

I believe that’s correct, Dieder, please feel free to correct me…  I’m heading out back to check out the same thing on my telescope in a few minutes! 
 

A couple of weeks ago, when we had that nice filament eruption, I could actually see plasma moving with my own eyes. At one point a jet of plasma erupted as a jet and then spread and thinned over the next couple of hours. 
 

Most of the experienced photographers use black and white imaging and then add false color in post processing. 
I guess what I’m saying is that, I would see the same thing as you are here, but it would be red, and the chromosphere of thee sun wouldn’t be blocked. 
This is why I’ve been so stoked since I got my h-a filter. Got us a nice sunny day, I’m hoping I’ll get a couple of hours of scope time in.

Cheers! 
WnA

12 minutes ago, WildWill said:

Howdy Orneno,

This isn’t a coronagraph - at least not one like you are used to seeing on LASCO. It’s just a nice H-alpha image. The sun has probably been blacked out in post processing the image. Here, you’re looking at features from the chromosphere and transition zone.  
 

You can see a number of H-alpha images on gong. They are pretty cool. I just got an H-a filter a couple of months ago, and this is the kind of thing that becomes visible…. I’m looking forward t getting my cameras connected. 
 

I believe that’s correct, Dieder, please feel free to correct me…  I’m heading out back to check out the same thing on my telescope in a few minutes! 
 

A couple of weeks ago, when we had that nice filament eruption, I could actually see plasma moving with my own eyes. At one point a jet of plasma erupted as a jet and then spread and thinned over the next couple of hours. 
 

Most of the experienced photographers use black and white imaging and then add false color in post processing. 
I guess what I’m saying is that, I would see the same thing as you are here, but it would be red, and the chromosphere of thee sun wouldn’t be blocked. 
This is why I’ve been so stoked since I got my h-a filter. Got us a nice sunny day, I’m hoping I’ll get a couple of hours of scope time in.

Cheers! 
WnA

Oh, thank you, that makes sense. 

Yes this is a real coronograph adding behind my 80/910 Vixen refractor as explain on the image.  You can see the original movie by this link : https://www.facebook.com/100000938727495/videos/pcb.8292155654158976/829844088281506

Edited November 1, 2022 by Didier Favre

2 hours ago, Didier Favre said:

Yes this is a real coronograph adding behind my 80/910 Vixen refractor as explain on the image.  You can see the original movie by this link : https://www.facebook.com/100000938727495/videos/pcb.8292155654158976/829844088281506

Really beautiful stuff! Thank you for sharing it. The features are beautiful, I love to look at them for a couple of hours at a time, live from my back yard. I got a DayStar H-alpha a couple of months ago - the chromosphere model. I caught a filament eruption a few weeks ago - it was just amazing! Can’t wait for the next one! 

I think it’s just a matter of terminology here. I don’t call it a coronagraph because we are not seeing any coronal features. Here we are looking at features in the chromosphere and upper transition zone. This is only possible with an H-alpha filter. The characteristic temperature is around 10kC. The temperature of the corona is measured in millions of degrees and aren’t visible in your images/movies. I think the thing you have will allow you to see these features of the chromosphere with a bit more contrast. They certainly are beautiful, but you can see the same features on GONG without the “artificial moon” from half a dozen stations around the world. You’ll notice there are differences in what you see, from image to image especially on the limbs. The reason is they have very slightly different CWL and or FWHM (band pass).  Changing the CWL, ever so slightly allows one to see features move towards or away from you- redshifted or blue shifted. Slightly varying the band pass allows one to see different features in the chromosphere, a larger (slightly) band pass.
Agsin, the reason I don’t call it a coronagraph is because you don’t see any if the features of the corona. It’s not like looking at the sun when you are in the totality of an eclipse and you can see the corona with your naked eye. Sorry for any confusion i may have caused by my earlier post. Again, I don’t call it a coronagraph because it’s showing features in the chromosphere, not the corona, but that may just be a difference in definition/terminology. 
 

I hope that makes sense. Again, beautiful stuff! Thank you for sharing! 
 

Cheers,

WnA

I stand corrected. It’s a coronagraph. My bad. Coronagraph has a broader definition than I thought. 
My apologies.

I erroneously came to the conclusion that you would see the corona. These features are all in the chromosphere and visible really well with my DayStar H-a filer.

Thr Corona is very interesting, but all the action happens in the chromosphere.  You’ve got some very nice pictures.

On 10/26/2022 at 4:03 PM, Orneno said:

Wow, I didn’t know you could do coronagraph images from the ground!

Hi Orneno,

You can’t do coronagraph images like you are used to seeing. Atmospheric dispersion, refraction and diffusion of light.

By definition, a coronagraph is a n instrument which blocks most of the suns light, so that one can see things close to the sun. This does not include the corona when used from the surface of earth.

With regards to the features seen here, you can obtain the same results without the “coronagraph” by using an H-a filter alone.

In other words, the H-a filter is already blocking almost all of the light from the sun by itself. You can see some H-a images of the sun on gong. The differences between images is because of very small differences in CWL and band pass. The band pass on an H-a filter is usually between 0.2A and 0.7A. With the larger band pass showing more prominences and the more narrow allows one to see more of the chromosphere. Check out DaystarFilters.com. They have some good educational material related to this.

Cheers.

WnA

Beautiful images. 

9 hours ago, WildWill said:

Hi Orneno,

You can’t do coronagraph images like you are used to seeing. Atmospheric dispersion, refraction and diffusion of light.

By definition, a coronagraph is a n instrument which blocks most of the suns light, so that one can see things close to the sun. This does not include the corona when used from the surface of earth.

With regards to the features seen here, you can obtain the same results without the “coronagraph” by using an H-a filter alone.

In other words, the H-a filter is already blocking almost all of the light from the sun by itself. You can see some H-a images of the sun on gong. The differences between images is because of very small differences in CWL and band pass. The band pass on an H-a filter is usually between 0.2A and 0.7A. With the larger band pass showing more prominences and the more narrow allows one to see more of the chromosphere. Check out DaystarFilters.com. They have some good educational material related to this.

Cheers.

WnA

Beautiful images. 

Darn that atmosphere, scattering light and hiding the corona. It would be so much better if we lived on the moon!

😂

2 hours ago, Orneno said:

Darn that atmosphere, scattering light and hiding the corona. It would be so much better if we lived on the moon!

😂

Maybe better for you, but I really don’t want to live in tunnels and warrens on a lifeless orb with no atmosphere. The 1/5 earth gravity would be nice, but I’m not ready to change palm trees and swimming’ holes for it. 
SAME for Mars. The most efficient means to develop a colony would be to build it underground, under at least 1 1/2m of water or 3m of Mars (dirt… it’s not earth, lol). You would need it as a radiation shield. On the surface and in spacecraft, there are shelter areas where the crew musters during radiation storms… 

Regardless, I decided in my 40’s I didn’t want to go to Mars. Too much work.