Where New Horizons is

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orin stepanek
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Re: Where New Horizons is

Post by orin stepanek » Mon Jul 27, 2020 11:17 am

bystander wrote:
Sat Jun 13, 2020 4:49 pm
New Horizons Conducts the First Interstellar Parallax Experiment
NASA | JHU APL | SwRI | New Horizons | 2020 Jun 11
For the first time, a spacecraft has sent back pictures of the sky from so far away that some stars appear to be in different positions than we see from Earth.

More than four billion miles from home and speeding toward interstellar space, NASA's New Horizons has traveled so far that it now has a unique view of the nearest stars. "It's fair to say that New Horizons is looking at an alien sky, unlike what we see from Earth," said Alan Stern, New Horizons principal investigator from Southwest Research Institute (SwRI) in Boulder, Colorado. "And that has allowed us to do something that had never been accomplished before — to see the nearest stars visibly displaced on the sky from the positions we see them on Earth."

On April 22-23, the spacecraft turned its long-range telescopic camera to a pair of the closest stars, Proxima Centauri and Wolf 359, showing just how they appear in different places than we see from Earth. Scientists have long used this "parallax effect" -- how a star appears to shift against its background when seen from different locations -- to measure distances to stars.

An easy way to see parallax is to place one finger at arm’s length and watch it jump back and forth when you view it successively with each eye. Similarly, as Earth makes it way around the Sun, the stars shift their positions. But because even the nearest stars are hundreds of thousands of times farther away than the diameter of Earth’s orbit, the parallax shifts are tiny, and can only be measured with precise instrumentation.

“No human eye can detect these shifts,” Stern said.

But when New Horizons images are paired with pictures of the same stars taken on the same dates by telescopes on Earth, the parallax shift is instantly visible. The combination yields a 3D view of the stars “floating” in front of their background star fields. ...
Has this caused any adjustments to be made in the distance to these stars; or to verify already known distances?
Orin

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neufer
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Re: Where New Horizons is

Post by neufer » Mon Jul 27, 2020 1:43 pm

orin stepanek wrote:
Mon Jul 27, 2020 11:17 am

Has this caused any adjustments to be made in the distance to these stars; or to verify already known distances?
From Earth's orbital baseline of 2 AU we have already determined
the parallax of Proxima Centauri as 0.7685 ± 0.0002 arcsec.

New Horizons's Long-Range Reconnaissance Imager (LORRI)
has a resolution of ~1 arcsec (= 5000 x 0.0002 = 20 x 0.05 Hubble resolution).

When New Horizons starts to approach 500 AU (= ~250 x 2 AU) away we will start
to improve on the parallaxes of all stars perpendicular to the Earth/New Horizons axis.
...................................................................................
Note:
Bright stars like Alpha Centauri have much poorer known parallaxes (e.g., 0.75481 ± 0.0041 arcsec)
so, I suppose, it is possible that one might be able improve on those now.
Art Neuendorffer

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bystander
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Re: The First Interstellar Parallax Experiment

Post by bystander » Mon Jul 27, 2020 7:56 pm

bystander wrote:
Sat Jun 13, 2020 4:49 pm
New Horizons Conducts the First Interstellar Parallax Experiment
NASA | JHU APL | SwRI | New Horizons | 2020 Jun 11

Las Cumbres Observatory Essential to Interstellar Parallax Experiment
Las Cumbres Observatory | 2020 Jul 27
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orin stepanek
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Re: Where New Horizons is

Post by orin stepanek » Fri Jul 31, 2020 11:45 am

Maybe I missed it; but did they find that the known established distance to Alpha Centauri, and the Wolf star were accurate? :shock:
Orin

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neufer
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Re: Where New Horizons is

Post by neufer » Fri Jul 31, 2020 12:12 pm

orin stepanek wrote:
Fri Jul 31, 2020 11:45 am

Maybe I missed it; but did they find that the known established distance to Alpha Centauri, and the Wolf star were accurate? :shock:
This is all about a Mr. Wizard/Bill Nye demonstration for Astronomy 101 texts.
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orin stepanek
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Re: Where New Horizons is

Post by orin stepanek » Fri Jul 31, 2020 2:45 pm

neufer wrote:
Fri Jul 31, 2020 12:12 pm
orin stepanek wrote:
Fri Jul 31, 2020 11:45 am

Maybe I missed it; but did they find that the known established distance to Alpha Centauri, and the Wolf star were accurate? :shock:
This is all about a Mr. Wizard/Bill Nye demonstration for Astronomy 101 texts.

OK!
Orin

Smile today; tomorrow's another day!