Revised/extended ephemeris quantities explanations

eph_expl.txt

@@ -64,10 +64,10 @@ midway between the vector from observer to target and the vector
 from sun to target.  This can be useful in analyzing light curves.
 # 34
 
-   The 'galactic confusion' is computed from star counts per unit
-area from Gaia-DR2.  Values range from zero (effectively no
-confusion) to 100 (densest parts of the Milky Way,  Magellanic
-Clouds,  or globular clusters).
+   The 'galactic confusion' is computed from star counts per unit area
+from Gaia-DR2.  Values range from zero (effectively no confusion) to
+100 (densest parts of the Milky Way,  Magellanic Clouds,  or globular
+clusters).  See https://projectpluto.com/gal_conf.htm for details.
 # 30
 
    'PsAng' is applied mostly to comets : it is the position angle at which
@@ -112,6 +112,10 @@ to look farther,  or not nearly as far,  as the uncertainties say.
 
    The object will probably be offset from nominal somewhere along the
 indicated position angle,  especially if the orbit is well determined.
+# 38
+
+   Three-letter constellation abbreviations specify the constellation
+containing that RA/dec,  as defined by the IAU's 1930 delineation.
 
 # Type 1   (state vectors)
 # Type 2   (positions)