What is the maximum distance that parallax error can be used?

using the Earths orbit, what is the maximum distance that can be measured using parallax error?

Dc2LightTech said:

TL;DR Summary: measuring astronomical distanced

using the Earths orbit, what is the maximum distance that can be measured using parallax error?

What accuracy/precision?

As @Bystander implies, there is no maximum distance. It depends on the accuracy of the position measurements.

Dc2LightTech said:

using the Earths orbit, what is the maximum distance that can be measured using parallax error?

How high is up?

Before putting too much effort into decrypting the question, one might want to take a peek at the OP's prior threads.

using the orbit around the sun, with current technology, how far can the best optical telescopes detect and parallax shift of a star using a distant galaxy as a reference for infinity.

Dc2LightTech said:

using the orbit around the sun, with current technology, how far can the best optical telescopes detect and parallax shift of a star using a distant galaxy as a reference for infinity.

Now you have a good question. What research have you done? What have you found so far?

And when you answer, please include whether you are talking earth or space based.

Dc2LightTech said:

using the orbit around the sun, with current technology, how far can the best optical telescopes detect and parallax shift of a star using a distant galaxy as a reference for infinity.

It isn't as simple as resolution, by the way. If you have a diffraction-limited telescope, the Rayleigh criterion will give you the ballpark for the angular separation needed to see two distinct points rather than one, and that's roughly what you need here - you need to be able to compare two images and say "yup, that point is in a different place". The figure comes out in radians. Convert to arcseconds, and one upon that is the number of parsecs you can use the method to.

Note that ground based telescopes may not be diffraction limited due to atmospheric conditions.

Also, as you noted that you need a background object to treat as a fixed point. So you need to have a reasonably large field of view to include an appropriate object or two, so you can be certain you've correctly matched your images. That's not always possible with a really high resolution telescope, so you may be forced to use a wider field telescope, or just observe something else.

Try Googling the Gaia mission from ESA. The data from Gaia is the current state of the art for astrometric accuracy.

Ibix said:

Note that ground based telescopes may not be diffraction limited due to atmospheric conditions.

I suspect they usually aren't.

Further, one could probably do better with ground base by extended observation. But while some stars might be valuable to do this with, why would you spend the obserrving time to do this with every satr? Delta Cephei makes a lot of sense. 9 Cephei, not so much.

phinds said:

Now you have a good question. What research have you done? What have you found so far?

if knew the pixel/angular resolution of the best sensor. and the typical Pixel/cross section for a faint star then calculation is not a hard thing to do. should be easy in LabView. I did a orbital flight dynamics program in Labview for fun. Moon landing from unlocking in orbit to touchdown. this should be easy. might be easy to simulate it.
I figure using the light time for the earths orbit as a leg, draw a triangle with the angle based on the resolution and calculate the distance to intercept. distance is in light time

And that gives no answer at all to your question. Have you actually researched your question? That is, not HOW do you do it, but what is the answer? That was your original question.

Changing questions after people have tried to answer your original question is considered bad form.

phinds said:

. Have you actually researched your question?

Of course he did. He told us to find the answer for him!

Dc2LightTech said:

if knew the pixel/angular resolution of the best sensor

You could certainly build a CCD with 50 nm pitch, and maybe even 5 nm, although I have no idea how you would power it up without it bursting into flames - each square cm would have 4 trillion channels.

But such a unit is not just smaller than what is normally used, it's smaller than a light wave. It would tell you nothing a more realistic unit with a larger pitch wouldn't.

We've spent a day trying to figure out exactly what you want to know. We still don't. Why don't you look up a bunch of stars in Wikipedia, see what their parallaxes and uncertainties are, and use that to calculate whatever number you are interested in?

It's not as simple as knowing the pixel resolution. Gaia is able to get angular accuracy much, much smaller than 1 pixel. It's worth looking up how they do that.