Imaging the Sun in white light
A Seestar S50 was fitted with an OD 5.0 Baader solar filter.
Click on an image to get a closer view.
A 3 minute RAW AVI was captured with the brightness control turned down so that there was no saturation in the blue channel. This was a photo captured to show the appearance of the Sun.
The best 50% of the frames in the AVI were debayered and stacked with 1.5 Drizzle in Autostakkert!4
The RGB image was decomposed into the 3 colour channels. The blue channel was the brightest and contained most of the information. The image was wavelet processed in waveSharp and further processed in the Gimp 2.10.
The Sun in white light
Imaging the Sun with a SeestarS50 and a combination of an OD 5.0 Baader solar filter and a Baader stacked Ca K-line filter.
The equipment comprised a holder for the OD 5.0 Solar film kindly 3D printed for me by SAS member John Beer.
This holder was attached to an Oak Optics adapter and a 2" to 1.25" adapter in which the Ca K-line filter was placed.
The sunlight would thus pass through the OD 5.0 solar safety film, through the Ca K-line filter and into the objective of the Seestar S50.
The equipment in action
A three minute RAW AVI was captured, but in this case it wasn't possible to control the exposure with the Brightness control as we did with the white light capture. In this case the manual controls of the exposure and gain were set to prevent the blue channel from overexposing. This resulted in a very dark blue preview.
The dark blue preview
Autofocusing was done while the image was on auto display and much brighter but had a completely overexposed blue channel
The dark blue RGB image was decomposed into the 3 colour channels. The blue channel was the brightest and contained most of the information from the CaK filter. The image was wavelet processed in waveSharp and further processed in the Gimp 2.10.
The Sun in Ca K-line light
Steve Wainwright and Nicola Mackin
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