Planning September 2021 for astrophotography
The lunar cycle is the single biggest variable for deep-sky imaging. Around full moon, sky background brightness can rise by 3–4 magnitudes per square arc-second, drowning out faint nebulosity. Around new moon, conditions return to baseline and 60–300 second sub-exposures on emission targets become viable.
The full moon for September 2021 falls on Mon 20 Sept. Plan lunar and high-contrast solar-system work in the days surrounding it; reserve dim galaxies, faint nebulae and integrated flux for the Sun 05 Sept–Thu 09 Sept window.
Phase data are computed from a custom port of SunCalc astronomical formulas and rendered live in your browser. For the interactive version with rise/set times for your location, open the live moon tool.