Today was a big day for me.

My 2026 edition of the Royal Astronomical Society of Canada Observer’s Handbook came in the mail today.
The RASC Handbook is published yearly and is a sort of almanac with ephemeral data useful to amateur astronomers,
but it is compiled with a detail and depth of value to professionals as well. Along with the ephemera (data which changes from year to year, like sunrise and sunset tables) it also contains many articles and listings of specific topics which are repeated yearly, but updated when new information is developed by ongoing research. Features on events of special interest are also included. There are tables of astronomical constants and observing tips. Even old editions are nice to keep around. There is plenty of material there to entertain you when you feel the need for reading material. I keep old copies in the bathroom, or give them to my friends. You don’t need to be an astronomer to treasure the Handbook, anyone with an interest in science will enjoy perusing it.

One of my favorite articles is “The Nearest Stars” by Todd J. Henry, which lists every known star within 5.0 parsecs (16.3 light-years). These are the closest known objects to the Sun, the ones we know the most about, and whose data has been determined to the highest precision. It is a detailed look at the solar neighborhood, and a useful sample of space in this corner of the galaxy. This a field of intense research and the list is updated frequently, and kept up to date.

The list contains 53 known systems comprised of 66 stars, 9 brown dwarfs and 13 known extrasolar planets. This catalog is constantly being updated by new observations, so I guess you could call this data “ephemeral”. Many of these guys are extremely faint, so new ones are turning up all the time. The brightest is Sirius (apparent magnitude -1.43). The faintest, Wise 1049-5319 B (apparent magnitude 24.07). They are also the intrinsically brightest and faintest, respectively. the nearest is Proxima Centauri (4.24 ly), the farthest, Omicron 2 Eridani (16.3 ly).

Forty eight of these stars are red dwarfs, spectral class M. Spectral classes O and B (the hottest) are totally missing from the list, and there is only 1 A and 1 F represented, the next lowest temperatures. Two share our Sun’s spectral class, G, while 8 are class K. (The spectral classes, from hottest to coolest are O,B,A,F,G,K,M.) The 5 white dwarfs, ancient, dying stars that have completed their evolution, are classed separately. The brown dwarfs are not stars at all, they glow from gravitational contraction only, they are to light and cannot maintain thermonuclear reactions in their cores.

These stars are listed in a table, with their names, positions, parallaxes (positions), proper motions (velocity across the line of sight) and radial velocity (towards or away from us), and their apparent magnitudes (how bright they appear) and their absolute magnitude (how bright they would appear at a standard distance of 10 pc). Also listed are their position angles (if they are binaries) and their spectral classes. Some of these fields are left blank, this field is still rapidly expanding.

This is what most of the Galaxy looks like, or at least the spiral arms and the disk. The brightest, hottest stars are also young, and the most short-lived, they can be seen at enormous distances, but they are extremely rare, even though they comprise much of the naked eye sky. The big red giants also are visible from afar, but they too are rare, and they are near death. The sample in this list is representative. It represents where we live.

The sky is like the sea, it contains whales and fishes, but most of the biomass is in the plankton.