Dec 23, 20231 minWhat is a Variable Star?A variable star's apparent brightness changes over time as seen from Earth. There are 2 basic types: intrinsic variables whose luminosity...
Nov 10, 20231 minWhat is a Cepheid variable?A Cepheid variable is a variable star that pulsates radially, varying in both diameter and temperature causing changes in brightness with...
Oct 14, 20231 minPtolemy's original 48 constellationsThe Greco-Roman Ptolemy listed 48 constellations after 150 AD. These were: Andromeda Ara Aries Aquarius Aquila Argo Auriga Boötes Cancer...
Oct 7, 20231 minWhat is a star?A star is a luminous ball of gas (mostly hydrogen and helium) held together by its own gravity. Nuclear fusion reactions at its core...
Sep 29, 20234 minHow are stars classified and what are stellar spectra?Stellar classification is usually based on two classification schemes, based on the star's surface temperature (the Harvard system), and...
Sep 17, 20231 minDoes the North Star Change?Yes due to precession. About 12,000 BC Vega was the North Star, lying approximately at the north celestial pole, not Polaris, and in...
Jul 25, 20231 minWhat Is An Asterism?An asterism is a small pattern or collection of stars that are not constellations, although they are often parts of a constellation: eg....
Jul 18, 20231 minModern ConstellationsThe sky is divided into 88 sections, known as constellations, which astronomers use to locate and name celestial objects. Most of the...
Jul 7, 20231 minWhat Makes 'The Summer Triangle' ?This is outlined by three stars: Vega, Deneb & Altair. The asterism 'The Northern Cross' (in the constellation Cygnus) is often used to...
May 20, 20231 minStar brightnessThe brightness of stars appears to be different, because they give out different amounts of light and they lie at vastly different...