Open Cluster ngc3766

Another target that will be redone at a later stage, once the Moon goes down, NGC3766, an open cluster that is in the general direction of the Running Chook Nebula. The Full Moon played havoc with the background and the RGB, as you can see. Did so even more with my m42 from that night, but this was hard enough to process. The cluster is 1745pc (5688.7ly) away and is 9.6ly in radius. The cluster has an apparent luminosity of 5.3mag and an integrated spectral type of B1.7. It contains around 137 stars, mostly B class stars and is relatively young, at about 14.4million years old. The cluster is approaching us at 14.8kms. Of it's 137 stars, 11 are Be stars (B class stars with emission spectra caused by circumstellar disks), 2 red supergiants and 4 Ap stars (A class stars with unusual metal rich spectra, usually associated with high surface magnetic fields). 36 of the stars are rather unusual B class stars that have a variability that ranges only across a few 100th's of a percent of magnitude over periods of around 1-2 a day. They are hotter than delta Scuti type variables but cooler than the slowly pulsating B stars. The cluster was discovered in 1751 by Nicolas-Louis de Lacaille as part of his sky survey, from Sth Africa. Pic was taken with t68 at the Bathurst Observatory (BAT-iTelescope Network). 15x60sec subs.
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