gray is night and light gray is astronomical twilight (Sun at less
than 18° below the horizon).
to left, each red dot is separated by one minute,
occultation time on the map, is for the big red dot, the closest
18 35 48.6931
DEC -19 17 43.617
18 36 35.1412
DEC -19 16 58.152
Star K mag
drop in R
Absolute time accuracy is essential to connect together all the
observations after the fact. Check the time of your computer with many
talked hour, different internet sites, ideally with a GPS). As images
should be acquired for a long time (10min at least), its advised to
check the registered time right after and
right before the integrations, so if there is a drift, we can correct
it by having the difference.
Beware of the dead time between the images. If you manage an exposure
of 1 sec (for example), but have your camera takes 2 sec to read the
image, then there is a
that you miss the dis(re)-appearance of the star. So it's better to
have, for example, a 4 sec integration, so you have 67% chance to get
occultation in one of your exposures.