I have tried to compare the Ephemeris data from Nasa's Horizons with ephemeris tables from astro.com. And they do not match. Example:
Date: 22th of July 2018. Body: Mars. Time 00:00 UT Horizons: 309 degrees (Ephemeris type=Observer) Astro.com: 305 degrees (http://www.astro.com/swisseph/ae/2000/ae_2018.pdf)
But some bodies are matching. Like Mercury and Saturn.
Am I doing something wrong?
Sources: Nasa Horizons: https://ssd.jpl.nasa.gov/horizons.cgi#top