Earth From Other Bodies

Earth from Other Bodies
Scripts for Stellarium

5 Files
1) Earth - Best views of from other bodies 2000-2100.ssc
2) Earth - Oppositions from Mercury.ssc
3) Earth - Oppositions from Venus.ssc
4) Earth - Greatest Elongations from Mars.ssc
5) Earth - Greatest Elongations from Jupiter.ssc

New in version 3.1

1) Fixed Typo in Jupiter Script

New in version 3

1) Greatest Brilliancies from Mars.
2) Screen Saver Mode
3) Magnitude, Phase, Moon calculations
4) More Menu choices

Instructions:

1) Download file
2) Extract the file into script directory
3) Run Stellarium
4) Open script
5) Run file
6) Follow Directions on script's main menu

Description:

1) Earth - Best views of from other bodies 2000-2100.ssc

Script contains the best date in the 21st century to view Earth from every other planet and our moon.

Planets / Date / Comment

Mercury: 5/31/2061 - Interestingly Mercury is closest to Earth while Earth is farthest from the sun.

Venus: 12/17/2093 - Closest Earth Opposition of the 21st century as seen from a floating city 50000 meters up.

Moon: 1/21/2023 - The moon becomes completely new (resulting in the brightest fullest Earth) within 4 minutes of Perigee

Mars: 7/26/2099 - Like Earth with Venus, Earth's greatest illumination doesn't happen on it's greatest elongation. The best one in the 21st century is in 2099 when Earth is particularly close and bright.

Ceres: 10/19/2082 - From Ceres the Earth has equally really bright greatest illumination dates at 23 and 9 year intervals. I went with 2082 because at the same time there's also a triple conjunction between Earth, Venus and Mars.

Jupiter: 7/15/2058 - 11.849°

Saturn: 9/15/2031 - 6.343° through the rings

Uranus: 6/16/2052 - 3.185°

Neptune: 7/17/2031- 1.952°

Pluto: 9/1/2000 - 1.934° - Every day in the 21st Century Pluto gets farther and farther from the sun (and thus Earth) so it's best view of course is right in the beginning,.

For the outer planets, for the best date, I use when the Earth is farthest angular separation (The greatest - greatest elongation) from the sun. The Earth will brighten from greatest elongation to superior conjunction, but because the angular separation is small if you were on these planets you wouldn't be able to see earth at other times.

The view from the gas giants is from the tops of their atmosphere.

Pressing the [ key turns on and off all flags and labels, this way

2) Earth - Oppositions from Venus.ssc

Script will show how, where and what Earth will look like during oppositions from a floating city on Venus.

Many scientist believe that it is not the Moon or Mars that we will colonize first, but instead we will colonize Venus. While the surface of Venus at 800°F is out of the question, humans might instead attempt to colonize the Venusian atmosphere in floating cities. This is because at an altitude of approximately 50 kilometers in Venus' upper atmosphere, the pressure and temperature are quite Earth-like (1 bar and 0-50 degrees Celsius).

On Venus, Earth will come into opposition about every 17 months, this script will show where and what Earth will look at on those opposition dates to anyone who is on one of these floating cities.

Latitude: As the start of the script the program will look to Polaris to get your latitude and it will use the same on Venus.

Longitude: Trying to calculate the best time to see an Earth opposition from a fixed longitude on Venus is pretty much way beyond my ability. Not to mention due to Venus' slow 243 Earth day rotation it might be many months after the opposition that Earth rotates into view. However, being in a floating city, longitude is not fixed so instead of time I just move the city to the longitude that's good to observe the Earth opposition. That's not too much of a stretch as at ~50000 km any floating city would rotate around Venus every 4 days which is more reasonable then 243. Lucky it's easy to calculate as Earth comes into oppositions just a little bit more than a half a degree longitude to the west of the previous one, so in order to keep Earth on screen I only have to shift longitude once 20 years.

3) Earth - Oppositions from Mercury.ssc

Script will show how, where and what Earth will look like during oppositions from the surface of Mercury.

Latitude: As the start of the script the program will look to Polaris to get your latitude and it will use the same on Mercury.

Longitude: Trying to calculate the best time to see an Earth opposition from a fixed longitude on Mercury has the same problems as Venus so I also had to change longitude to follow the opposition. Though it's much more difficult as there are 3 oppositions at 3 separate spaced out longitudes in a year. There is however a repeating pattern. The next 3 oppositions shift are the same as before except shifted ~9 Degrees to the east, for example if a set of 3 oppositions have a overhead longitude of W117, 0, E135 then the next 3 will be W108, E9 and E144 and the next W99, E18 and E152 which will result in a 40 year repeating pattern.

When I was making this program I had the current cycle (1,2 or 3) and Longitude displayed to help me figure out this pattern. I left it in just as a FYI

4) Earth - Greatest Elongations from Mars.ssc

This script will show what Earth will look like on Mars on the dates when it reaches it's greatest elongation and it's greatest brilliancy.

Due to the eccentricity of Mars' orbit it's also more variable. Earth can separate from the sun between 38° and 47°

And due to the eccentricity unlike with Venus on Earth where Venus' Greatest elongation occurs about a month before or after it's elongation, Earth is more variable. Sometimes it's the same day, sometimes it's a month before or after and everything in between

Longitude: I use my own 175E and -14S for the script. This is where the Spirit Lander landed and where the Landscape is, the initial times start the search for the best time to display Earth. You can move the latitude and it will adjust. the script will search until it finds either

A) When the sun is 11 and 17 Degrees below the horizon
or
B) When Earth is more than 3 degrees above the horizon

Initially it might take a second or two to find the best time and when it does it will remember the time and if you come back to that same elongation the script will know when is the best time to start looking thus cutting down on searching time.

I put a limit, The script will only search for 3 seconds, if it doesn't find a good viewing time it will stop. This is to prevent the script for searching forever in Polar regions (and maybe near polar regions when the planet "runs high" or "rides low") when the sun is up for 24 hours (or close to it) or the Planet is below the horizon for 24 hours. To cut down on this I limit the latitude.

Mars comes particularly close to the Earth near it's opposition approximately every 15 - 17 years i.e. 2003, 2018, 2035, etc, during these times Mars is at it's brightest as seen from Earth. However these years aren't particularly impressive when viewing Earth from Mars, but approximately 2 years before (during morning greatest elongations) and 2 years after (during evening greatest elongations) these close encounters, Earth will have it's largest Greatest Elongations and best showing as seen from Mars.

5) Earth - Greatest Elongations from Jupiter.ssc

This script will show what Earth will look like on Jupiter on the dates when it reaches it's greatest elongation.

Earth at it's Greatest Elongation as seen from Jupiter separates only between 10.2° to 11.9° from the sun

Latitude and Longitude: Since Jupiter has pretty much no tilt I set the Latitude at the equator, and longitude I used my own. The sunset/sunrise times are pre-determined, there is no searching around like in the GE from Mars script.

I chose the altitude of 71,492,000 meters (Jupiter's radius) because
a) Earth is too close to the sun so it's lost in the dawn/dusk,
b) Jupiter's atmosphere is so thick you wouldn't be able to see it (or anything else).

So the top is the only place you would have a chance of seeing Earth

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Elongation: The separation in degrees between the planet and sun.

Greatest Brilliancy: When the planet is brightest.

Magnitude: The brightness of the planet. Depending on what source you use, magnitude values vary widely. I use th JPL and my calculations for Earth seem to come about -0.3 magnitudes brighter than Stellariums.

Illumination: This is the percent the planet that is sunlit as visible from earth.

Moon Elong: The separation in degrees the moon is from the earth as seen from the planet

Moon Mag: The magnitude of the moon. My calculations seem to match Stellarium's pretty closely

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No I didn't type all these years and times out. I wrote a computer program based on Paul Schlyter's work at

http://www.stjarnhimlen.se/comp/ppcomp.html

which produced all these values.

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My dates I calculated do seem to match other dates from a wide variety of sources, but I make no guarantee on accuracy.

I'm sure accuracy decreases the further back or forward in time any given script goes.

I can be emailed at qam1@aol.com