In episode 304 astrologer Patrick Watson joins the show to talk about how to use an ephemeris to study the movements of the planets in astrology.
An ephemeris is a book of planetary positions that lists where the planets will be in the zodiac in the past, present, or future.
In the past it was used by astrologers in order to calculate birth charts by hand, but these days it is mainly useful for studying planetary transits and cycles.
During the course of the episode we give a detailed introduction to the ephemeris, talk about some of the things you can do with it, and how to use it to improve your technical skills as an astrologer.
For more information about Patrick check out his website:
PatrickWatsonAstrology.com
This episode is available in both audio and video versions below.
Ephemeris Episode Outline and Show Notes
Here is an outline of some of the main points discussed in the episode:

Definition: what is an ephemeris?
Definition from Google/Oxford Languages:

“a table or data file giving the calculated positions of a celestial object at regular intervals throughout a period.”
“a book or set of such tables or files.”

An ephemeris is just a listing of planetary positions.
A handy way of tabulating the data.
Gives you the ability to look at large compilations of data at a glance.
Pronounced e·phem·er·is
Ephemeris is the singular, while the plural is ephemerides.
There are different types of ephemerides
Astrodienst ephemeris available online for free (Swiss Ephemeris)

Astro.com > All about astrology > 9000 years ephemeris

Astro-Seek ephemeris:

Astro-seek.com > Astro Tools > Ephemeris Tables

The American Ephemeris is the printed ephemeris we use and recommend

It is the most common one among US astrologers at this point.
So we will focus on that and the Astrodienst ephemeris

There are different varieties of the American ephemeris.

Primary difference is year ranges

How the main one to get at this point is the trans-century ephemeris for 1950-2050
Midnight versus noon ephemeris

Midnight version starts the day at midnight
Noon version starts the day at noon
Difference is negligible for most planets, so either will do.
I usually use the noon version so that you know where the planets are mid-day

Prerequisites for using an ephemeris

Memorizing the glyphs for planets and signs
Memorizing the aspects ranges between planets

Understanding planetary movements
Ephemeris displays longitudinal movements of the planets through signs of the zodiac

Along the ecliptic, which is the path of the Sun

Breaking down the info shown on a page of the American Ephemeris

Month, year, day
All the planets and their longitudes and whether direct or retro
Stations, ingresses, last aspect of Moon
Moon phases and eclipses
Miscellaneous astro data: asteroids, galactic center, mean node

Direct versus retrograde motion

American Ephemeris shades retrograde planets, which is a nice feature

Seeing how fast or slow different planets move.
It shows what degree and minute each planet is at at the start of the day

Unless you use the noon version
You have to infer based on planetary speed where it is during the day

How to Read an Ephemeris

The Astrology Podcast