Solar System Ephemires
For Stellarium 10
Files
Solar system screensaver.ssc
Version 1
Instructions:
1) Download zip file
2) Extract the files
3) Run Stellarium
4) Run scripts
5) Run file
6) Move to date to see what the body would look like and where it would be
General Notes:
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Unfortunately there's no "Get latitude" or "Get longitude" functions in Stellarium scripts, so when you 1st run any of the scripts, they will first attempt to calculate your position and your offfset from UTC. It won't get your location exactly, but it should be close enough that the set and rise times won't be significantly different.
It calculates lat by your angle to the North Star
It then calculates long by starting at "12 noon" UTC and then seeing when Solar Noon is at your location. The difference is your longitude.
If you find this annoying or want more accuracy, you can open any of the script files in notepad (or equivalent) and manually enter your lat and long where it says lat and long.
When you 1st do this you will notice the initially lat and long numbers don't make sense, this is done on purpose.
If lat and/or long are in there normal ranges (lat is anything between -90 and 90 and long is between -180 and 180) then the program will use those values, if the lat and/or long are out of range then the program will attempt to determine them.
You have to enter lat and long in decimal form. There are many online coversions out there or to convert from Degrees, minutes, seconds to degress in decimals
Degrees + minutes/60 + seconds/3600
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As such, if you let the script estimate lat and long, Rise and Set times can be off by up to 10 minutes.
If manually put your exact lat and long in the script file, rise and set times are accurate to 1 to 2 minutes.
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Whatever date you move to, the script will go to the best time at that date to view the planet. When the planet is west of the sun, that will be when the planet rises and gets 10° abobve the horizon. When the planet is east of the sun, the script will go to dusk when the sun is about 15° below the horizon. Sometimes this is not possible, especially at highetr latitudes or when the planet rides very high/runs very low, in these cases the program will try and find the best viewing time.
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Transit times are always the date you are on, the rise and set times are calculated from it. If a rise or set time is before or after midnight when compared to the transit time, then they are the previous or next day respectively.
For example if the date is March 27,
If for Mars the rise/transit/set times are
Rise: 23:00
Transit: 07:00
Set: 15:00
Then Mars rose 23:00 on March 26th, transits 07:00 March 27th and sets 15:00 on March 27th
If for Jupiter the rise/transit/set times are
Rise: 09:00
Transit: 17:00
Set: 01:00
Then Jupiter rises 09:00 on March 27th, transits 17:00 March 27th and sets 01:00 on March 28th
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Transit: When the body crosses the merdian.
Elongation: The seperation in degrees between the planet and sun.
RA Elong: The Right Acsension separation between sun and body
Magnitude: The brightness of the planet. Depending on what source you use magnitude values vary from source to source. For example some sources claim Venus max brightness is -4.4 while others have it at -4.9 and everything in between. As such my calculations for Venus are slightly different than Stellarium. For example where as in Stellarium Venus' brightest magnitudes are about -4.55 mine are about -4.85. Jupiter and Earth (though not the moon) also come out slightly different in my calculations. I base my calucations off the JPL Horizons site and my magnitudes seems to match theirs.
The biggest difference is Saturn, Stellarium doesn't factor ring tilt where my script does. So the more the rings are tilted the bigger the difference between my script and Stellarium.
Rides High / Runs Low: This is the declination difference between the sun and planet. When the planet rides high it is above the sun, runs low it is below. In the Northern Hemisphere when the planet (especially inferior ones) "rides high" it is more easily viewable and when it runs low even though it might have a large elongation from the sun it could be hard to view. In the Southern Hemisphere the opposite is true so "runs low" is better.
Ring Tilt: The tilt of Saturn's rings.
Illumination: This is the percent the planet that is sunlit as visible from earth.
Phase Angle: This is the angle from the planet to the sun and earth. Range is from °0 to 180°. If it's zero the planet appears "full", if it's 90 degrees it appears "half", and if it's 180 degrees it appears "new". Only the Moon and Mercury and Venus can have phase angles exceeding about 50 degrees. Interestingly the phase angle is also the elongation from the sun the earth would be if you were on the planet.
Earth Shine: This is the phase the Earth would be if you were on the planet
Earth Mag: This is the magnitude the Earth would if you were on the planet
Moon Mag: This is the magnitude the moon would be if you were on the planet
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Please do check out ephemires from the polar regions, it took me quite a bit to get them right
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Because viewing times are based on the date you select and the calculations are based on Julian date it is possible to get stuck on a date or "jump" over a date, especially when your local time and UTC time is a different date. I put in checks to prevent this from happening, but still might happen. If it happens, try move ahead or back by a week instead of a days and go back to the date you want.
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A link to a site that deserve credit for helping me predict, find & make these scripts
http://www.stjarnhimlen.se/comp/ppcomp.html
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My dates and data 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. Especially for Pluto.
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I can be emailed at qam1@aol.com