Visibility IV / V
I tried to highlight the MAXI J1820 + 070 light curve of the black hole in the lightening spring work, from Arto's tip. I photographed the subject in UV narrowband 387nm / 15nm, 30 exposures for 2 minutes, ie for just over an hour until the sky was too light. The hourly light curve became quite clear with a 0.20mag dimming. The absolute magnitudes are indicative because the reference stars of that particular 387nm wavelength were not known and I used the stars of region B TYC 444-2474-1 B12.25 and TYC 444-2630-1 B11.51 as some kind of calibration and BD + 07 3641 B11.10 as a reference. The second image shows a single 120s exposure with MAXI J1820 + 070 and reference stars marked.
The last two images in the visual band with the IDAS LPS-P2 filter with 5 minutes exposure, the MAXI location marked in the crop.
My SGP seems to have stamped the original FITS -3h incorrect times, the correct time for the JD time scale is + 3h / JD + 0.125.