(*TEST* flat inverted) --- filter B, bin 2, night 230421, compared to previous night 230419, sigma = 0.0045 --- (flat / previous inverted)
(*TEST* flat inverted) --- filter R, bin 2, night 230421, compared to previous night 230419, sigma = 0.0047 --- (flat / previous inverted)
(*TEST* flat inverted) --- filter V, bin 2, night 230421, compared to previous night 230419, sigma = 0.0065 --- (flat / previous inverted)