Distance Calculations

[fosborn_]

For example, objects 3253-693-1, 2853-306-1 & 4828-1651-1 have parallaxes of -799.8, -904.4 & -919.1 respectively, which means if they actually moved in the correct direction compared to their backgrounds, would all be closer than Alpha Centauri at 742.1

I queried SIMBAD and got zero results on finding these objects.
And sense this is a science thread not NIMI, its good form to post your sources.

You need to try harder. They're easy to find. Have fun.

<moderator edit - offensive statement removed>
( this is a science thread not NIMI, its good form to post your sources)

But not to waste a post:

Aardwolf wrote:
Errors in measument and motion is taken into consideration. These are genuine negative parallax measurements and there more than just a few anomalies. They are counted in the thousands.

Quite exaggerating IMO. Got a source to show your alleged facts?
Sorry not to trust, you don't come accross as a unbiased observer.

Some 20,000 distances were determined to better than 10%, and 50,000 to better than 20%.

Hipparcos Catalogue:
Number of entries 118,218

http://en.wikipedia.org/wiki/Hipparcos

You sure are vague about this. Which group are you referring to, the 10% or the 20% or the remaining 48000?
<moderator edit - offensive remark removed>

[Aardwolf]

Anyone familiar with SIMBAD may wish to use the criteria query function and enter plx < 0.

Let me know how many you find.

[fosborn_]

Anyone familiar with SIMBAD may wish to use the criteria query function and enter plx < 0.

Let me know how many you find.

First of all, thanks. I didn't think of that. And it works on my blackberry!

But 4277. Out of 118000? Sorry dude, not a show stopper.
But tonight on my PC I will do more analysis. Is that 3.6% error?

[Aardwolf]

And the cause of the "errors"?

[fosborn_]

For example, objects 3253-693-1, 2853-306-1 & 4828-1651-1 have parallaxes of -799.8, -904.4 & -919.1 respectively, which means if they actually moved in the correct direction compared to their backgrounds, would all be closer than Alpha Centauri at 742.1

Can't find these objects in the wild card search or adding HIP designator in front of them. Want to provide a link? Or query ?

went through the list of 4277, your objects not there.

[fosborn_]

Science has decided that becasue they are positive we trust them but all the negative ones we can ignore because they dont fit. That's not science..

Nope, they expose all the errors they can and after listing them and all the reasons for them, they compare that against the good results. Then decide how valid the good results are.
That's why science has many many more failures than fairy tell success stories. At lest that's the story when a hands on scientist tells it.

[Aardwolf]

Science has decided that becasue they are positive we trust them but all the negative ones we can ignore because they dont fit. That's not science..

Nope, they expose all the errors they can and after listing them and all the reasons for them, they compare that against the good results. Then decide how valid the good results are.
That's why science has many many more failures than fairy tell success stories. At lest that's the story when a hands on scientist tells it.

Err..if they dont know what all the errors are how do they dertermine what the good resuts are? How do they know if their goods results have been tainted by an unknown error.

[Aardwolf]

The problem with the negative parallax "errors" is that they're not just some single data point or an error caused by a miscalculation etc. It took over 3 years to determine the parallax measurements with at least 30 observations for each object. For a negative parallax to be an "error" it would require all of those measurements to be consistently in error for the same direction and magnitude.

It's a problem with theory not the measurements.

[fosborn_]

The problem with the negative parallax "errors" is that they're not just some single data point or an error caused by a miscalculation etc. It took over 3 years to determine the parallax measurements with at least 30 observations for each object. For a negative parallax to be an "error" it would require all of those measurements to be consistently in error for the same direction and magnitude.

It's a problem with theory not the measurements.

You cast doubt on parallax, its just math and its works.

I don't know, I can't find your objects, to even see what your talking about. What is the proper motion of your examples, what are the notes posted about it.
Do you what to use objects actually in the HIP catalog? Lets start from there.
You say things, but are shy on posting solid data for full context. When I discover context, your argument weakens, so far IMO. example 3.6% .

[Aardwolf]

The problem with the negative parallax "errors" is that they're not just some single data point or an error caused by a miscalculation etc. It took over 3 years to determine the parallax measurements with at least 30 observations for each object. For a negative parallax to be an "error" it would require all of those measurements to be consistently in error for the same direction and magnitude.

It's a problem with theory not the measurements.

You cast doubt on parallax, its just math and its works.

I don't know, I can't find your objects, to even see what your talking about. What is the proper motion of your examples, what are the notes posted about it.
Do you what to use objects actually in the HIP catalog? Lets start from there.
You say things, but are shy on posting solid data for full context. When I discover context, your argument weakens, so far IMO. example 3.6% .

Why would I spoil your fun looking for them.

And you're right, its maths and it does work. But stellar parallax measurement should never produce any negative results let alone thousands so there is something wrong. A single data point error may be acceptable, not a consistent repeated error over 3 years. They're not errors they are genuine unexplained measurements.

[fosborn_]

And you're right, its maths and it does work. But stellar parallax measurement should never produce any negative results let alone thousands so there is something wrong. A single data point error may be acceptable, not a consistent repeated error over 3 years. They're not errors they are genuine unexplained measurements.
Aardwolf

Right, you have to have good proper motion for it to work. So those don't have good proper motion measurements, it didn't work.
Parallax still works with the good measurement. 20000 @ 10% accuracy, 50000 @ 20%. They didn't hide anything, a sign of good science.

went through the list of 4277, your objects not there.
fosborn_

[Aardwolf]

Right, you have to have good proper motion for it to work. So those don't have good proper motion measurements, it didn't work.

So you know those negative parallax stars didn't have good proper motion data. Did you research this or have you just made it up?

Luckily SIMBAD can help us out. Go to the criteria search and type in;

plx<0 & pmqual=a

Tell us how many you find that, by your own determination, are good measurements we can trust.

[fosborn_]

Aardwolf wrote:

For example, objects 3253-693-1, 2853-306-1 & 4828-1651-1 have parallaxes of -799.8, -904.4 & -919.1 respectively, which means if they actually moved in the correct direction compared to their backgrounds, would all be closer than Alpha Centauri at 742.

Sorry your objects still not listed. You got a line number to reference them too?

So you know those negative parallax stars didn't have good proper motion data. Did you research this or have you just made it up?

I ask the same question?

[Aardwolf]

So you know those negative parallax stars didn't have good proper motion data. Did you research this or have you just made it up?

I ask the same question?

You dont need to ask me. Why don't you query SIMBAD? Don't you trust it?

[fosborn_]

Aardwolf wrote:

For example, objects 3253-693-1, 2853-306-1 & 4828-1651-1 have parallaxes of -799.8, -904.4 & -919.1 respectively, which means if they actually moved in the correct direction compared to their backgrounds, would all be closer than Alpha Centauri at 742.

Sorry your objects still not listed. You got a line number to reference them too?

I made the query you suggested and your objects should have been listed. They weren't in the list.
So I have doubts they exist.
Are they in that list and have you typed the accurate ID name that the list uses?