Hi David,

"...There MUST be a way of determining dates of Earth Perihelion
and Aphelion..."

I appreciate your confidence in Guide. Unfortunately, I have
to admit that in this case, it's misplaced.

The only way I can see to compute peri/aphelion for the earth
(or any planet) in Guide is to "go to" the sun for some dates/times
around 3 January or 3 July, click on the sun, and ask for 'more
info'. Do this, and Guide will give a distance to the sun for
those date/times, and one can find the exact date/time with a bit
of searching.

Be sure to select the "geocentric" check-box in the Settings...
Location dialog.

Actually, all of this does give me an idea for a more general
"max/min distance" option. You would select an object, and ask
Guide to find the next time that the object comes closest/is farthest
from you. Do this for the sun, and you would get times of
apogee/perigee. Do it for a near-earth asteroid, and you could
get its time of closest approach. Set your "home planet" to be
the sun and click on a planet or asteroid (or your "home planet"
to be any planet or asteroid and click on the sun), and you would
get the perihelion/aphelion times for that object. Similarly, one
could get perigee/apogee times for artificial satellites.

-- Bill