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4 Feb 2023 21:10:00 EST (-0500)
  Planetarium (Message 11 to 16 of 16)  
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From: Stephen
Subject: Re: Planetarium
Date: 15 Sep 2018 07:13:38
Message: <5b9ce962$1@news.povray.org>
On 15/09/2018 11:58, Stephen wrote:
>      rotate    <20.000,0.000,0.000>

That might be -19 to -21 not rotate 20*x

-- 

Regards
     Stephen


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From: Mike Horvath
Subject: Re: Planetarium
Date: 15 Sep 2018 08:11:44
Message: <5b9cf700$1@news.povray.org>
On 9/15/2018 6:58 AM, Stephen wrote:
> On 15/09/2018 11:43, Mike Horvath wrote:
>> I have textures, but do not know how to orient them with respect to 
>> the axial tilt, orbit and sun. Is anyone familiar with how to do this?
>>
>>
>> Mike
> 
> For Z up Left handed scenes.
> 
> 
> texture {
>    pigment {
>      image_map{
>        png "F:\Graphics\B3D Data\Maps\Planets\Earth\EarthMap2.png"
>        interpolate 2
>        map_type 1
>      }
>      rotate    <20.000,0.000,0.000>
>    }
> 
> Then for orientation in an orbit. Rotate the sphere the planet texture 
> will follow.
> 

Thanks. But which direction does the axis tilt with respect to the Sun 
on a given day?


Mike


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From: Stephen
Subject: Re: Planetarium
Date: 15 Sep 2018 09:01:34
Message: <5b9d02ae$1@news.povray.org>
On 15/09/2018 13:11, Mike Horvath wrote:
> On 9/15/2018 6:58 AM, Stephen wrote:
>> On 15/09/2018 11:43, Mike Horvath wrote:
>>> I have textures, but do not know how to orient them with respect to 
>>> the axial tilt, orbit and sun. Is anyone familiar with how to do this?
>>>
>>>
>>> Mike
>>
>> For Z up Left handed scenes.
>>
>>
>> texture {
>>    pigment {
>>      image_map{
>>        png "F:\Graphics\B3D Data\Maps\Planets\Earth\EarthMap2.png"
>>        interpolate 2
>>        map_type 1
>>      }
>>      rotate    <20.000,0.000,0.000>
>>    }
>>
>> Then for orientation in an orbit. Rotate the sphere the planet texture 
>> will follow.
>>
> 
> Thanks. But which direction does the axis tilt with respect to the Sun 
> on a given day?
> 
> 


Earth currently has an axial tilt of about 23.4° and the angle does not 
change. With respect to the Sun on a given day, it depends on there it 
is in its orbit.
https://en.wikipedia.org/wiki/Axial_tilt#Earth

So if you start your Planetarium at the summer or winter equinox. The 
mechanics will take care of themselves.
I think. :)



-- 

Regards
     Stephen


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From: Mike Horvath
Subject: Re: Planetarium
Date: 16 Sep 2018 14:31:41
Message: <5b9ea18d@news.povray.org>
Latest version is attached. It is *very* close, but the Earth is off by 
about one month's worth of travel.

Here is the document I am using as a guide:

https://ssd.jpl.nasa.gov/txt/aprx_pos_planets.pdf

And I am using this website to compare my render to:

https://in-the-sky.org/solarsystem.php

Set it to JD 2458376.5, which is equivalent to A.D. 2018 Sep 15.

I am not sure where my calculations have gone wrong.


Mike


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Attachments:
Download 'orrery_sphere_trail_new.pov.txt' (25 KB)

From: Mike Horvath
Subject: Re: Planetarium
Date: 16 Sep 2018 14:53:43
Message: <5b9ea6b7$1@news.povray.org>
On 9/16/2018 2:31 PM, Mike Horvath wrote:
> Latest version is attached. It is *very* close, but the Earth is off by 
> about one month's worth of travel.
> 
> Here is the document I am using as a guide:
> 
> https://ssd.jpl.nasa.gov/txt/aprx_pos_planets.pdf
> 
> And I am using this website to compare my render to:
> 
> https://in-the-sky.org/solarsystem.php
> 
> Set it to JD 2458376.5, which is equivalent to A.D. 2018 Sep 15.
> 
> I am not sure where my calculations have gone wrong.
> 
> 
> Mike


If you zoom out, Jupiter is also in the wrong place, so Maybe my results 
are *not* so close after all.


Mike


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From: Mike Horvath
Subject: Re: Planetarium
Date: 16 Sep 2018 22:49:40
Message: <5b9f1644$1@news.povray.org>
Updated the scene. It is working correctly now.

:)


Mike


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Attachments:
Download 'orrery_sphere_trail_b.pov.txt' (29 KB)

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