Stellar Distances

This post has more to do with astronomy than astrology but I firmly believe that the best way to defend astrology from its detractors is to have a solid understanding of astronomy. Many critics of astrology have a poor understanding of astronomy and arguments, for example, that astrology does not take the precession of the equinoxes into account when formulating horoscopes can be easily refuted. Recently, with access to a deck that affords a good view of the night sky, I've been using the software program Stellarium to identify the more prominent celestial objects. This is the same program that Graham Hancock uses to view the sky as it appeared in Egypt and other places in antiquity thousands of years ago. He mentioned this in his latest book, Magicians of the Gods, that I just finished reading.

I like to know how far various stars and nebula are from our solar system and Stellarium reveals this immediately. By just clicking on the object, an information pane appears on the left of the screen. In the diagram below, I've listed the major stars in the constellation of Canis Major along with their distances to the nearest light year:

As can be seen, with the exception of Sirius, all the major stars are fairly distant. Sirius of course is an object of considerable fascination for stargazers of the past and present. Here is some information about it taken from Wikipedia.

Sirius, a romanisation of Greek Σείριος, Seirios, lit. "glowing" or "scorching") is a star system and the brightest star in the Earth's night sky. With a visual apparent magnitude of −1.46, it is almost twice as bright as Canopus, the next brightest star. The system has the Bayer designation Alpha Canis Majoris (α CMa). What the naked eye perceives as a single star is a binary star system, consisting of a white main-sequence star of spectral type A0 or A1, termed Sirius A, and a faint white dwarf companion of spectral type DA2, called Sirius B. The distance separating Sirius A from its companion varies between 8.2 and 31.5 AU. 

Sirius appears bright because of its intrinsic luminosity and its proximity to Earth. At a distance of 2.6 parsecs (8.6 ly), as determined by the Hipparcos astrometry satellite, the Sirius system is one of Earth's near neighbours. Sirius is gradually moving closer to the Solar System, so it will slightly increase in brightness over the next 60,000 years. After that time its distance will begin to increase and it will become fainter, but it will continue to be the brightest star in the Earth's night sky for the next 210,000 years. 

Sirius A is about twice as massive as the Sun (M☉) and has an absolute visual magnitude of 1.42. It is 25 times more luminous than the Sun but has a significantly lower luminosity than other bright stars such as Canopus or Rigel. The system is between 200 and 300 million years old. It was originally composed of two bright bluish stars. The more massive of these, Sirius B, consumed its resources and became a red giant before shedding its outer layers and collapsing into its current state as a white dwarf around 120 million years ago. 

Sirius is also known colloquially as the "Dog Star", reflecting its prominence in its constellation, Canis Major (Greater Dog). The heliacal rising of Sirius marked the flooding of the Nile in Ancient Egypt and the "dog days" of summer for the ancient Greeks, while to the Polynesians in the Southern Hemisphere the star marked winter and was an important reference for their navigation around the Pacific Ocean.

Below are the major stars and nebulae for the constellation of Orion, along with their distances in light years:

Again, all the stars are reasonably distant but I was surprised to learn the Great Nebula in Orion was actually within our own galaxy and so I've included some information about it from Wikipedia. I'm sure I'll learn a lot more as I continue viewing the night sky in tandem with the astronomy software.