return siderealTime if libnova is available
return siderealTime if libnova is available

olegkutkov/phd2guiding_crao,olegkutkov/phd2guiding_crao,olegkutkov/phd2guiding_crao,olegkutkov/phd2guiding_crao,olegkutkov/phd2guiding_crao,olegkutkov/phd2guiding_crao