Can you interpret this?

[Ags]

I shot three images with my Solar Scout 60 tuned to -5, -3 and 0. At 0 it seems filaments are more apparent, while at -5 the active region is more smokey and the surface is more contrasty... But which of these settings is "correct"? Judging with an eyepiece I seem to prefer -3. Maybe I shout try +3 too?

In any case, what do these differences mean? Am I seeing different altitudes of hydrogen with each setting?

Apologies for the quality of the images. I was experimenting to avoid the need for flats by drifting the sun aorund the sensor, but if the technique works, I have not mastered it. 

Edited April 25, 2022 by Ags

[inFINNity Deck]

Hi Ags,

I do not know the Solar Scout, but I recognise the differences when imaging with my Lunt LS80THA. I always try to tune my Lunt to have an even illuminated solar disc as contrast can be improved by using a non-linear stretch in IMPPG. If I look at your images, then 0-setting is spot-on, while the others result in uneven illumination, marked in red in below copy of your images:

In processing I can easily deal with the left image, but cannot get rid of the dark section of the middle one or the banana-shaped dark section in the right-hand image.

So I would go for setting 0.

Nicolàs

 

[Victor Boesen]

If I were you, I'd try to shoot some images ranging from [0,5]. As already pointed out, the 0-position image looks more even and flat, however, what catches my eye is the amount of contrast around the faculae of the AR's comparing the three images. If centered on the H-alpha line the contrast of faculae will be the greatest!! And judging from these pictures, it's easy to see that 0 yields the greatest amount of contrast. So try to get some images on the positive dial side, as it looks like you might get the best results there (or at 0).

Victor

EDIT: To add to your actual question. If on the blue wing of the H-alpha wing, eg. shorter wavelength, you will see gas moving towards Earth. This means spicules are often more obvious in the blue wing, as they're gas rapidly being lifted above the chromosphere. In the red wing, you will see gas moving away from Earth.

Edited April 25, 2022 by Victor Boesen

[Ags]

Yes, looking at the pictures it seems 0 is the best. I'll try shoot some new tests at -1, 0, and 1.

[Ags]

This was shot at f18 by the way (aperture 52 mm). One problem I have with tuning set to zero is the surface texture is finer and lower contrast, and AS3! struggle to stack the edges.

[Ags]

I think we are on the right track. Here is +0 vs +2. Took a lot more care over focus today and shot with aperture slightly reduced to 43 mm for a bit more contrast. Will try 52 mm again tomorrow.

Both images are sharpened and stretched identically im IMPPG and then colorized identically in GIMP.