When you a see an "R" beside a planetary position it means that the planet is in retrograde or backward motion. Planets always move forward, but due to different orbital distances and speeds a planet will sometimes be overtaken, and appear to slow down, stop, and go backwards.
Only the Sun, Moon, and Earth (Ascendant) do not have a retrograde motion.
In Astrology, retrogrades are Piscean in nature signifying a turning inward, a loss of power, karma, or negative tendencies brought over from a past life. The planet that is retrograde and the sign or house it is in, and its relationship to the other planets (aspects) will all describe the nature of this loss or weakness in your life.
On average, most people have two or three retrograde planets, signifying past lessons that have not been learned or resolved. Some people, however, can have as many as five or six (heavy karma), and others none at all (clean slate). Below are the planets and what they signify when when retrograde.
Mercury retrograde: in past lives you have spoken or written carelessly or in a negative manner (especially if Mercury is badly placed or expected) and in this life you are paying for it by being shy, quiet, or fearful of speaking up for yourself. Others may talk down on you or criticize you for no apparent reason.
Venus retrograde: in past lives you have been too selfish or indulgent (especially if Venus is badly placed or expected) and now you must give more of yourself and exercise restraint if you are to be successful in your dealings with others.
Mars retrograde: in past lives you were too aggressive or impatient with others (especially if Mars is badly placed or expected) and now you feel helpless to defend yourself or initiate anything.
Jupiter retrograde: in past lives you abused your wealth and influence and compromised your morals by indulging in liquor and sex and gambling (especially if Jupiter is badly placed or expected). In this life, you must become more ethical and disciplined if you are not to repeat your mistakes and further debase yourself.
Saturn retrograde: in past lives you were very mean, cold, heartless, and stingy, thinking only of your status, wealth, and power or control over others (especially if Saturn is badly placed or expected). In this life you have no ambition or power, or find it very difficult to maintain, and may now be at the mercy of others.
Uranus retrograde: in past lives you were a rebel, revolutionary, or scientist who caused a lot of mayhem (especially if Uranus is badly placed or expected). In this lifetime, you may be tempted to repeat your rabble rousing but it will backfire and make you the victim instead. Whatever you do, you must be totally honest and humane, otherwise you will invite trouble.
Neptune retrograde: in past lives you were very deceptive and immoral attracting scandal and persecution (especially if Neptune is badly placed or expected). You lied and cheated and refused to face reality, and may have even committed suicide, and in this lifetime it is very easy for you to fall into the same traps unless you exercise discipline and faith.
Pluto retrograde: in past lives you resorted to criminal acts and lascivious behavior (especially if Pluto is badly placed or expected), and in this life you may be subject to same.