H-alpha solar imaging question...

[Odd Thomas]

Hi folks, I have a question as above.

I know nothing about imaging so please bear with me..

I look at the fantastic solar H-alpha images on here and some are upwards of 1000 frames which are then 'stacked'.

I can understand why one would do this with a faint galaxy or other DSO, but why is this done on the sun? is there not enough light to capture in just 1 frame?

My guess would be that it's to capture more detail, but does the detail in the surface features not move, hence blurring the image(s)?

Thank you.

[JacobvonChorus]

As I understand it, people do this to capture many frames so they can select the few where the seeing was much better than the others, and therefore the detail is much better. Then those frames can be stacked to reduce noise.

Jacob

[NickK]

Also if the frames are in a short enough period (ie little elapsed time) then they can be stacked using drizzle to increase the resolution.

[Odd Thomas]

Thanks for that guys. I had to Google 'drizzle' though! So its all a matter of better resolution and more detail then. Cheers.

[ollypenrice]

A camera measures things. Each pixel makes a measurement. Any measurement has error bars. That's measurement. If you measure anything 100 times and add the result then divide it by 100 you will get a much better measurement... There are further advantages since the reference image in the stack is human brain-selected but more measurements, averaged, mean more precision.

Olly

[Ibbo!]

and the seeing is usually not too good in the day with all that heat from the sun unless you are imaging not too long after sunrise so the idea is take loads of frames and stack the good ones