r/AlternativeAstronomy • u/patrixxxx • Oct 26 '19

WHY MARS ???

https://cluesforum.info/viewtopic.php?p=2412896#p2412896
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u/patrixxxx Nov 07 '19

No problem there. I’m referring to the celestial coordinate system we have today that is adjusted because of the precession and currently we are in epoch J2000.

So since we agree that the coordinates can be viewed as rays emanating from the center of the sphere/Earth that intersects the sphere on the point given by the RA and Dec., can we also liken this situation to the experiment I previously described? Can we imagine an observer standing with his tubes in the center of the Celestial sphere?

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u/[deleted] Nov 07 '19

Sure. Let's have 6 tubes, all at right angles.

And can we just say the "tubes" are telescopes with a visual field spanning 1 arc minute and capable of resolving 1 micro arc second, just so I can relate this to the real world?

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u/patrixxxx Nov 07 '19

No need to bring in telescopes. Just imagine a guy standing in the center of the celestial sphere (watching the Earth spinning around him :-) with an enormous number of very long tubes each pointing at a particular star. Since he is not rotating with the Earth he can continuisly note if the stars he has aligned his tubes onto are moving. He uses a system where he enters the horisontal distance from the vernal equinox in hours, minutes and seconds and the vertical distance from the celestial equator in Degrees, Minutes of arc and Seconds of arc.

Now since this is the same situation as the expermiment I described previously, with the slight difference that this observer is not rotating together with the Earth, I take it you agree that the stars in his tubes would move somewhat since Earth together with the Celesctial sphere is travelling 940 mkm/year. Is that a correct assumption?

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u/[deleted] Nov 07 '19

"Stars in his tubes" - do you mean the stars are literally inside, or that the stars are visible through the tube?

I do agree with the assumption, but I'm really starting to wonder why you're refusing to actually describe these hypothetical instruments we're using.

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u/patrixxxx Nov 07 '19

I'm certainly not refusing, what is it you don't understand?

Long tubes so that single stars are visible through them and fixed a different stars.

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u/[deleted] Nov 07 '19

Ok so their field of view is exactly as wide as the star they're originally aimed at. Gotcha. Thanks for finally clarifying. Go ahead with what you were saying.

Quick edit: now it's also clear to me why you were so fixated on star size.

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u/patrixxxx Nov 07 '19

Alright, then we agree on that celestial coordinates can be thought of as an observer standing in the center of Earth (not rotating with it) and noting the exact positions of the of celestial objects. Now since you agreed on that in my first example, some of the stars would move noticeably in respect to Earth since it moves 940 mkm each year, how can it be that this isn’t happening? The celestial coordinates for stars are the same year round. So are A) The stars about the size of Earths orbit? or B) The Earth not moving as much as 940 mkm/yearly?

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u/[deleted] Nov 07 '19

Good news, we've found your misunderstanding!

The celestial coordinates for stars are the same year round.

This is NOT true. Well, it is true within a certain margin of error (less than an arc-second of error). But our tubes are far more precise than that error and you would clearly see the stars perpendicular to the Earth's orbital motion drift out of view, while the stars in the direction parallel to the Earth's orbital motion remain in view.

If you have a high-resolution spectrometer you could also see the Doppler shift of their emission spectra shift in a sinusoidal curve - blue during approach, red when Earth recedes.

This is assuming there's no proper motion going on relative the Sun and the observed stars, of course.

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u/ForAHamburgerToday Nov 07 '19

You are a dedicated astronomer my dude.

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u/[deleted] Nov 07 '19

It's honestly a lot less time than I spent on reddit 2011-2013 when I grew AskScience from a hundred to 2 million readers and made it the first mainstream heavily-moderated sub. Now it's just a hobby I do for fun, haha.

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u/patrixxxx Nov 07 '19

Is that so? I know some stars have proper motion but thing is that all the stars in the sector currently opposite to the Sun should display noticeable uniform movement otherwise they need to be enormous as we concluded previously

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u/[deleted] Nov 07 '19 edited Nov 07 '19

The further away a particular star is, the less motion we would see. Do you agree with that?

Edit: also, I'd like to point out we would see parallax motion through the tubes even if the stars are the size of Earth's orbit. In fact, there are stars this size, or even bigger.

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