The sky over London was clear and the air was quite still today so even better results were obtained in the most recent testing of the long chrome/quartz slits (for the previous test run see viewtopic.php?t=36602). I used the setup from the day before to take four H-alpha scans and then tuned the grating to the H/K lines of Calcium. The focus points for all three optics needed to be adjusted slightly at the shorter wavelength but this did not take too much time. The results at CaK looked a little nicer than the ones at CaH so I present CaK and H-alpha.
Since I was using no attenuation (e.g. ND filter) of the solar energy, the shutter speed could be kept at 1ms for both H-alpha and CaK. The gain for H-alpha was 9% and for CaK it was 30%. Both ROI had a length of 3200, with the H-alpha width 180 and for CaK 200 (the greater width was needed because the CaK line is significantly wider than H-alpha). The H-alpha scan rate was 12x sidereal rate and 10x for CaK (since the FPS was 257 and 231).
For the H-alpha processing I again used Valerie Desnoux's software Solex_ser_recon v3.3.0, while for CaK, I used our own Solex_ser_recon_EN version 3.2 (https://github.com/thelondonsmiths/Sole ... s/tag/v3.2). Hers gives much fewer line errors with H-alpha, while ours works better on Calcium images.
H-alpha and CaK full-disk SHG images -- plus CaK proms
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Re: H-alpha and CaK full-disk SHG images -- plus CaK proms
These are just absolutely incredible, some of the best SHG images I have ever seen
Alexandra
Alexandra