I am still trying to get to grips with my Sol'ex and still making some fairly fundamental mistakes. Focussing, particularly at the UV end of the spectrum is very tricky. The image is quite dim on the screen and to maintain the 10mS maximum exposure time, a certain amount of camera gain is required. This adds noise which can compound the focussing problems.
Nonetheless, a couple of nice images while on holiday in Cromer.
The Sun in Hydrogen Alpha (Ha). A little bit underexposed and the spicules are not as clear as they could be. A very large (long) filament clearly visible. Sunspots can be seen through the chromosphere on the surface of the photosphere,
This image in Calcium H at the UV end of the spectrum. The active regions are much more clearly defined, spicules (the large granulation) are visible and the larger sunspots are also visible. AR 3712 is at the lower right with AR 3713 just above. AR 3716 is above and slightly to the right again. West (astronomical convention) is to the right and North upwards.
Compare with the WL image of the photosphere here: https://www.spaceweather.com/images2024/20jun24/hmi1898.gif
This image is in Calcium K, further into the UV end of the spectrum. Apart from the fact I inadvertently cropped the bottom of the image, this is very similar to the Calcium H image above. Calcium K accentuates the spicules and active regions even more, look at the NW and NE sections of the hemisphere where the difference is clearer to see. The downside is that it is more difficult to focus and position the image on the PC screen.
2024-06-20 10:05 - 010:50 UTC
60mm F4 Refractor stopped down to 36mm
ND9 filter to reduce light and heat intensity
Sol'ex spectroheliograph
EQ5 plus RA Drive
ZWO ASI178MM Camera
Processed SharpCap4.1, jSolex
(c) Martyn Kinder 2024