psGravityDeflection definition

[David.Robbins@…]

the SDRS 7.5.1.2 (rev 17) says,
the following function calculates the apparent position of a star, given its
actual position and the position of the sun.

I believe the "apparent" and "actual" got switched here. ie., you're
calculating the actual position given the apparent and the position of the sun.

[David.Robbins@…]

same thing for psAberration. I've switched the order so they read,

psSphere *psAberration(psSphere *actual,

const psSphere *apparent,
const psSphere *direction,
double speed)

and
psSphere *psGravityDeflection(psSphere *actual,

psSphere *apparent,
psSphere *sun)

[Paul Price]

No, I think the SDRS got it correct. We know the actual position of the star,
and want to calculate the apparent position (so we can point the telescope at it).

Ed?

[pier]

Paul is correct here that the tranform goes from actual to apparent.

To be pedantic, this is more of a convention than an exact mathematical fact.
The error you get by switching the actual and apparent directions would
be of the same order as the error due to the first order approximation
used in the formula.

[David.Robbins@…]

Ok. I switched the arguments back to the way they were.