wrote:


One assignment would be to measure the distance to
Alpha Centuri by triangulation and not parallax.

Parallax is the perception of distance due to motion. In
astronomy, it is frequently done using the annual motion
of Earth about the Sun giving annual parallax. But if you
do it with the motion of a spacecraft instead of the motion
of Earth, it is still called parallax.


I do GeT confused easily.


We've noticed.


But stellar parallax is a relative
angle to background stars?


Not quite. It's the apparent shift in position of an object against
the far background from two different observing positions.

https://en.wikipedia.org/wiki/Stellar_parallax


In my view an angle-side-angle triangulation measure computes
the distance. Not a relative angle to the background stars.


Your view is, as usual, myopically incorrect. They are essentially
the same thing. Take a trigonometry class.


A parallax baseline as the two points in a sun orbit with
a known length and the angle of parallax appears relative
to the unknown distance to the background stars.

So the field of cosmological stars is a simple progression
without a firm initial value.


False.


--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn