SolarChat!

Dear All,

I was nearly one year since the last time I use my 300 mm solar telescope.

Last Saturday morning, the conditions were not very promising. The wind came from Nord-West, which usually is not good for the seeing. And the sky was coronal, which is not good either. On top of that there was not a single spot or even a small pore in view.

Having re-collimated the scope during the previous night, I decided to give it a try anyway just to check my collimation on the Sun.

I started with a red filter (656 nm), then switch to a green filter (540 nm), to a blue/green filter (500 nm) and finally to the 430 nm (G band filter).

Accordingly, this sequence shows the increase of contrast and resolution when going from red to violet light.

Here are the images.

Red light (656 nm), the contrast is prety low, but this filter is less sensitive to the seeing :



Green light (540 nm), the contrast is much better :



Green/blue light (500 nm), the contrast and resolution are still better. Usually, this is the optimal filter for my place :



G band (430 nm). This one is a different world since the intergranular bright spots and filigrees become visible. This is the first time ever I have these seeing conditions at my place :-)



Best regards

Christian Viladrich

Awesome cells! And the comparison of filters is really helpful!

Very best,

Christian:
Superb high resolution images.
Best wishes,
Eric.

Fantastic granulations, Christian.

Franco

These images are excellent no matter what filter is chosen Christian...superb work

Brian

My!!!!! I wish I had seeing like that, I don't have a hope. These are absolutely gorgeous

Alexandra

Wonderful (all of them). Very useful to have the comparison to refer too as well. Thanks for that.
Brilliant!
Robert

The brilliant granulation shots!!
Val

Hi Christian,

I am very impressed with the G-band image. Other are quite nice too, but the G-band is something special.


Valery

AMAZING resolution Christian. Brilliant, I'm speechless

I noticed that you combined more images this time (15 to 30 images)

Thanks to all :-)

Valery : I agree with you, the G band image has something of its own. The granulation cells are very diffentiated with different levels of shades.

Pedro : you've got a keen eye ;-) The seeing was really oustanding for these images. Even better than what we experienced last August at St Veran observatory (2930m). This made it possible to stack more images.

What an impressive set of images, Christian. I find it a bit difficult to differentiate the 540nm and 500nm images as far as contrast is concerned. They both look amazingly crisp. I agree with Valery. The G band image is terrific with many bright points visible. Wonderful!

Cheers, Peter.

Thanks Peter,
I have updated the 500 and 540 nm images. Now, the processing of both images is consistent. In the previous version, I had applied a more agressive filter to the 540 nm image, which resulted in a reduction of the difference between both images.

Hi Christian,

Your white light images are so noise-fee, unbelieveably noise-free. Do you use any special de-noising software?

I tried white ligth imaging many times include under a very good seeing. Tried de-noising in PS CS6, Topaz. Not even close to what your images are.

Thanks,


Valery

Hi Valery,
The processing for photopheric images is very simple. I just apply an unsharp mask (sigma = 1.4 pixel, k = 8). Nothing else.
Best regards
Christian

Exceptional images Christian and an excellent comparison!

christian viladrich wrote: ↑Tue Jul 10, 2018 3:10 pm
The processing for photopheric images is very simple. I just apply an unsharp mask (sigma = 1.4 pixel, k = 8). Nothing else.

Hi Christian,

Thanks for the tip. I will try it with my images.

To understand how good can be the images for such a simple processing, can you, please, show us here the unsharpened stacked image and one of the staked frames (an individual single frame).

Do you use a more complicated processing for CaK and H-a images?


Thanks,


Valery

I think this is just outatnding raw data in the first place Valery

superbe Christian , bravo !!!!


Paul

marktownley wrote: ↑Wed Jul 11, 2018 11:16 am I think this is just outatnding raw data in the first place Valery

Yes, I agree. But what is a miracle for me is that I have no problems with CaK data processing and Ha data. Not so easy with continuum data.
So, I would like to understand how to process the continuum raw images maximally effectively - minimal noise with delicate shades.
And this G-band image looks like etalon for photospheric features imaging. We can do a little against the seeing, but we can do different processing!


Valery