In my column of Sept. 6 I said: "Uranus will enter Sagittarius on Nov. 16, 1981." A reader,objecting to this statement, sent a letter to the editor (Sept. 25) and wrote: "In reality, Uranus has not left Librae since October 1976, and will enter this year Scorpii, not Sagittarii, one month later, in December." He also suggested that I "ought to break down and buy an ephemeris for 1981."

Since his letter generated numerous inquiries (by letter and phone) from readers of this column who asked me to explain what the letter meant, I will try to do so.

First of all, I do have not one, but several current ephemerides. The ephemeris I use for this column is "Raphael Astronomical Ephemeris," published in England. It shows noon positions for all the planets, Greenwich time, London Observatory (besides other data).

Accordingly, Uranus enters Sagittarius on Nov. 16, 1981, more specifically, at 6:32 a.m. EST (6:24 a.m. EST for Washington, D.C.). At that moment Uranus will leave the sign of Scorpio and will not return there for 74 years.

As for the strange data presented by the writer of the letter, I can explain it only by presuming that he developed some kind of time machine that took him back, all the way into the Nixon and Ford administrations, and into a universe that is all his own. It is a universe where the planet Uranus remains in a sign for only five years (October '76 until December '81) instead of its customary seven years. It is also a universe where there is not just a single Libra constellation, a single Scorpius constellation, a single Sagittarius constellation, but multiples thereof, since his Uranus travels through "Librae," "Scorpii," and "Sagitarii" -- all of those endings being Latin plural endings of Libra, Scorpius and Sagittarius (or his Latin needs brushing up).

Inasmuch as I received additional data on the Redskins, and in response to another inquiry, I would like to add a few words to my column of Sept. 20.

Edward Bennett Williams, co-owner of the Redskins, was born on May 31, 1920, and has his Sun in Gemini. He also has planets that fall between zero and seven degrees of mutables (his Saturn-Uranus opposition from Virgo to Pisces) and thus, like everyone else on the Redskins team, will be affected by the Uranus entry into Sagittarius (the first crucial months will be from November through April). It confirms my previous prediction that there are changes coming, possibly in the ownership of the team.

This Uranus entry into Sagittarius, affecting so strongly all the Redskins charts I have studied, makes any other planetary influences pale by comparison. And yet, when I read the other day that substitute quarterback Tom Flick will not replace Joe Theirsmann, I have to dispute that, from a purely astrological point of view.

First of all, from the standpoint of sheer luck, the chart of Flick falls beautifully on coach Joe Gibbs' chart. Flick's Jupiter, a lucky planet, is in exact conjunction with Gibbs' Venus, the planety that rules Gibbs' career and can enhance it. Theismann's Jupiter, on the other hand, does nothing for Gibbs.

But while the charts of Gibbs and Theismann look superficially compatible, in reality they are not. The charts of both men indicate they both like to be unusual, original, daring, aggressive and startling. There is a great deal of show-offishness in their charts. However, Gibbs wants to show off mentally, while Theismann wants to show off physically.

Joe Gibbs' chart indicates an incredible amount of self-discipline. And even though he wants to startel people by his game plan, to shock them and to draw attention to his original thinking, those bursts of creativity are rooted and firmly disciplined, he also demands of his players. If he were a piano teacher, his pupils' technique would have to be flawless before they could attempt a performance.

Theismann's chart on the other hand, indicates that he has difficulty in disciplining himself in all areas of his life.

And thus, even though both men wish for the same result, their methods are different and are based on different premises, making any unified effort difficult.