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How do you follow a star?

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  How do you follow a star? john <johnsefton288@gmail.com> - 2016-12-24 16:05 -0800
    Re: How do you follow a star? moroney@world.std.spaamtrap.com (Michael Moroney) - 2016-12-25 05:57 +0000
    Re: How do you follow a star? pnalsing@gmail.com - 2016-12-24 22:08 -0800
    Re: How do you follow a star? Yuri Kreaton <invlaid@invalid.com> - 2016-12-25 08:12 -0600
      Re: How do you follow a star? Yuri Kreaton <invlaid@invalid.com> - 2016-12-25 12:54 -0600
        Re: How do you follow a star? john <johnsefton288@gmail.com> - 2016-12-25 10:59 -0800
          Re: How do you follow a star? Yuri Kreaton <invlaid@invalid.com> - 2016-12-25 13:20 -0600
            Re: How do you follow a star? Sylvia Else <sylvia@not.at.this.address> - 2016-12-26 11:40 +1100
              Re: How do you follow a star? john <johnsefton288@gmail.com> - 2016-12-25 20:03 -0800
                Re: How do you follow a star? Sylvia Else <sylvia@not.at.this.address> - 2016-12-26 16:08 +1100
                  Re: How do you follow a star? Yuri Kreaton <invlaid@invalid.com> - 2016-12-26 00:08 -0600
                    Re: How do you follow a star? Sylvia Else <sylvia@not.at.this.address> - 2016-12-26 23:06 +1100

#610306 — How do you follow a star?

Only if it's geostationary 

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#610338

john <johnsefton288@gmail.com> writes:

>Only if it's geostationary 

What are you babbling about now? Stars can't be geostationary, only
satellites at a certain distance can.

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#610339

On Saturday, December 24, 2016 at 4:05:16 PM UTC-8, john wrote:

> Only if it's geostationary

BZZZZT! Try again...

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#610350

On 12/24/2016 6:05 PM, john wrote:
> Only if it's geostationary
>


those "stars" are sattilites in geosyncronous orbit.

and you can follow them in the night time, clear sky out, if you brought 
your telescope.

but I dont know how you would get close, or under it on the earth, it 
would be in a 500 mile radius from POCA,


Extra Credit Question:

what is math behind determining how close you can get to "undernieth" 
the sattilite, using a portable telescope ?

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#610356

On 12/25/2016 8:12 AM, Yuri Kreaton wrote:
> On 12/24/2016 6:05 PM, john wrote:
>> Only if it's geostationary
>>
>
>
> those "stars" are sattilites in geosyncronous orbit.
>
> and you can follow them in the night time, clear sky out, if you brought
> your telescope.
>
> but I dont know how you would get close, or under it on the earth, it
> would be in a 500 mile radius from POCA,
>
>
> Extra Credit Question:
>
> what is math behind determining how close you can get to "undernieth"
> the sattilite, using a portable telescope ?

simple tan function, distance = 22,236mi/(tan(89)) = 388 miles, assuming 
your telescope and such, has 1 degree error or less.

that would  be the radius of a circle on earth where underneath the 
satellite, the angle is 89 to 90 degrees. 90 degrees would be underneath.

So about an 800 mile diameter, so how can a star lead you to a point on 
a sphere ?

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#610358

Yuri
"So about an 800 mile diameter, so how can a star lead you to a point on 
a sphere ? "

Maybe it can rotate with the earth
at a very low altitude 
with high technology.
(1100 mph).
Then, how high to be seen by
the Wise Men?

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#610360

On 12/25/2016 12:59 PM, john wrote:
> Yuri
> "So about an 800 mile diameter, so how can a star lead you to a point on
> a sphere ? "
>
> Maybe it can rotate with the earth
> at a very low altitude
> with high technology.
> (1100 mph).
> Then, how high to be seen by
> the Wise Men?
>

I dube this the "Wise Men" Problem,

what is the orbiting altitude of a geosecrynous sattilite such that it 
can guide 3 Wise Men with good telescopes (1 degree error), to with 10 
mile of a place on the earth ?
(within 10 miles they could ask around)

22,236/x = 388/10   (simple ratio)

or  x = 22236/388 * 10 = 570 miles up which has satellite drag



So, Extra Credit:

how long before hand do they have to launch a LEO at 570 miles above 
earth surface, so the Wise Men, on camels, can get there in 12 days ?

(assume spherical sattilite)

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#610370

On 26/12/2016 6:20 AM, Yuri Kreaton wrote:

> what is the orbiting altitude of a geosecrynous sattilite such that it
> can guide 3 Wise Men with good telescopes (1 degree error), to with 10
> mile of a place on the earth ?

I think you've been watching too much television.

All geosynchronous satellites orbit at the same altitude. They have to. 
There's no choice in the matter. They're also all in equatorial orbits.

Sylvia.

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#610381

Sylvia
"
I think you've been watching too much television. 

All geosynchronous satellites orbit at the same altitude. They have to. 
There's no choice in the matter. They're also all in equatorial orbits. 

Sylvia. 
"
See Yuri's comment on "satellite drag".
Presumably, one neutralizes that, somehow

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#610384

On 26/12/2016 3:03 PM, john wrote:
> Sylvia
> "
> I think you've been watching too much television.
>
> All geosynchronous satellites orbit at the same altitude. They have to.
> There's no choice in the matter. They're also all in equatorial orbits.
>
> Sylvia.
> "
> See Yuri's comment on "satellite drag".
> Presumably, one neutralizes that, somehow
>

No, and there's negligible drag on a satellite in geosynchronous orbit 
anyway.

Sylvia.

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#610386

On 12/25/2016 11:08 PM, Sylvia Else wrote:
> On 26/12/2016 3:03 PM, john wrote:
>> Sylvia
>> "
>> I think you've been watching too much television.
>>
>> All geosynchronous satellites orbit at the same altitude. They have to.
>> There's no choice in the matter. They're also all in equatorial orbits.
>>
>> Sylvia.
>> "
>> See Yuri's comment on "satellite drag".
>> Presumably, one neutralizes that, somehow
>>
>
> No, and there's negligible drag on a satellite in geosynchronous orbit
> anyway.
>
> Sylvia.

I think that bounds the "Wise Men" problem,
if you have to use a star (or satellite) as an indicator of a fixed 
position on earth, then it must

	1.  be in the geosync height, 22,230 miles up, to remain stationary w 
earth surface.
	2.  fixed position can only be on equator.

so, the question is,

How did the Wise Men navigate using a star to get to Middle East, 
Israel, Bethlehem, then manger  ?

  they must have had the location, astrolabe, and timepiece?... or map 
with route.

or was it a moving star ?

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#610395

On 26/12/2016 5:08 PM, Yuri Kreaton wrote:
> On 12/25/2016 11:08 PM, Sylvia Else wrote:
>> On 26/12/2016 3:03 PM, john wrote:
>>> Sylvia
>>> "
>>> I think you've been watching too much television.
>>>
>>> All geosynchronous satellites orbit at the same altitude. They have to.
>>> There's no choice in the matter. They're also all in equatorial orbits.
>>>
>>> Sylvia.
>>> "
>>> See Yuri's comment on "satellite drag".
>>> Presumably, one neutralizes that, somehow
>>>
>>
>> No, and there's negligible drag on a satellite in geosynchronous orbit
>> anyway.
>>
>> Sylvia.
>
> I think that bounds the "Wise Men" problem,
> if you have to use a star (or satellite) as an indicator of a fixed
> position on earth, then it must
>
>      1.  be in the geosync height, 22,230 miles up, to remain stationary
> w earth surface.
>      2.  fixed position can only be on equator.
>
> so, the question is,
>
> How did the Wise Men navigate using a star to get to Middle East,
> Israel, Bethlehem, then manger  ?
>
>   they must have had the location, astrolabe, and timepiece?... or map
> with route.
>
> or was it a moving star ?

Clearly it wasn't something in geosynchronous orbit.

If there was a real bright object (nova, say) more or less stationary 
relative to the fixed stars, then following it may have meant going in 
the direction in which it rose (or fell) with the turn of the Earth.

Or it may have been an ephemeral object like a meteor, and the men just 
continued in the direction it had appeared.

It all see seems rather far fetched. More likely, it didn't exist at 
all, and is just an embellishment of the story.

Sylvia.

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