Solar activity 13 Jan 2022 - Mg (b2)

[Merlin66 (Ken)]

Still hampered by strong winds but managed to get a reasonable MiniSHG image in the wavelength of Mg (b2)
All the current active areas and regions of faculae visible - AR 2924/5/6/7/8
plus these a bit of faculae up in the north east....
Enjoy

[John W (John Wilkinson)]

Thats an improvement on the first images Ken. More details showing up. Keep working on it. Regards John W.

[Eris (Gerard)]

Yes Ken, I am in agreement with John re improvement with sharpness and details shown in this Mg image. Definitely going in the right direction in my opinion.

[Merlin66 (Ken)]

Thanks guys.
The current weather has been very frustrating.
I can’t seem to get enough good clear spells to bed down any marginal improvements.
Onwards and Upwards

[N1 (Mirko)]

Always interesting to see what's happening on the Sun, and in different wavelengths. Your SHG work does both Ken, great stuff!

Maybe it's been mentioned elsewhere and I missed it, but how long does it take to produce a single image with the SHG?

[Merlin66 (Ken)]

Mirko,
Depending on your setup it can take between 120 sec and 9 sec.
If you just let the solar disk drift across the slit it's 120 sec. If you use the slew buttons on your mount (ie x2 or x3 sidereal) you can get down to 9sec.

The other issue is obtaining sufficient frames during the scan video.
The size of the solar disk is close to 1/100 the telescope focal length. An ED80 for example gives a solar image of 5.6mm, using an ASI 178 camera with 2.4 micron pixels this equals 2327 pixel.
To get a pretty close to circular scanned image (to minimise geometric corrections) you then need to record approx 2327 frames. This leads to a frame rate of 2327/9 = 258 fps.
(With the drift method you'd only need 2327/120 = 19.4 fps)
Hope that helps.
(Oh, it takes around 3-4 sec (!!!) to process the video into an image. The INTI software is very fast.)