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planetephem
Josh Cardenzana edited this page Mar 20, 2017
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This page outlines the executable planetephem that provides the ephemeris for a planet over a user specified time interval.
USAGE: planetephem [options]
Returns the RA,Dec and observed Az,Alt coordinates for a given planet for a given observer.
| Short | LongOption | Type | Default | Desciption |
|---|---|---|---|---|
| -h | --help | Prints out this help information. | ||
| -d | --duration | double | 1440.000000 | Duration for printing out results (in minutes). Results will be printed from 'startJD' to 'startJD + duration'. Default is for one 24 hour period |
| -e | --elevation | double | 0.000000 | Observer elevation (meters above sea level) |
| -a | --latitude | double | 0.000000 | Observer geographic latitude (degrees) |
| -l | --longitude | double | 0.000000 | Observer geographic longitude (degrees, east positive) |
| -t | --startJD | double | current time | Starting time as a Julian date. Default will be the current Julian date |
| -s | --step | double | 30.000000 | Number of minutes between each line of the print out. |
| -p | --planet | int | 0 | Planet number (1=Mercury, 2=Venus, 4=Mars, 5=Jupiter, 6=Saturn, 7=Uranus, 8=Neptune) |
Note: Type planetephem -h for a full description of options in your version.
To run this script you will need to know the following bits of information:
- Your geographic longitude,latitude (in degrees)
Additionally, more accurate results can be obtained by providing the following bits of information:
- Your elevation (meters above sea level, defaults to 0.0 meters)
For this example we will assume the observer is located in Toulouse, France:
- Longitude: +1.444 degrees
- Latitude : +43.605 degrees
- Elevation: 150 meters
To query the positions of VENUS over the next 24 hours we simply type
planetephem --planet=2 --longitude=1.444 --latitude=43.605 --elevation=150The output for this (at least when I just ran it) is as follows (you will get different results depending on the current date you are querying on):
= OBSERVER ===================
Longitude: +1d 26m 38.4s
Latitude : +43d 36m 18.0s
Elevation: 150.000000 m
LocalTime: 10:21:16.1
= PLANET =====================
Name : Venus
Mass : 4.868500e+24 kg
Radius: 6051.800000 km
Albedo: 0.650000
JD LOCAL RA DEC Az Alt
=======================================================================
2457820.89 102116.1 0h 34m 15.6s +11d 54m 53.1s 101.922 +29.276
2457820.91 105116.1 0h 34m 15.6s +11d 54m 53.1s 107.990 +34.535
2457820.93 112116.1 0h 34m 14.6s +11d 54m 57.7s 114.680 +39.606
2457820.95 115116.1 0h 34m 13.5s +11d 55m 2.2s 122.209 +44.396
2457820.97 122116.1 0h 34m 12.4s +11d 55m 6.7s 130.829 +48.775
2457820.99 125116.1 0h 34m 11.4s +11d 55m 11.2s 140.792 +52.576
2457821.01 132116.1 0h 34m 10.3s +11d 55m 15.6s 152.263 +55.586
2457821.04 135116.1 0h 34m 9.2s +11d 55m 20.0s 165.156 +57.570
2457821.06 142116.1 0h 34m 8.1s +11d 55m 24.4s 178.977 +58.326
2457821.08 145116.1 0h 34m 7.0s +11d 55m 28.7s 192.868 +57.763
2457821.10 152116.1 0h 34m 5.9s +11d 55m 33.0s 205.940 +55.950
2457821.12 155116.1 0h 34m 4.8s +11d 55m 37.3s 217.635 +53.076
2457821.14 162116.1 0h 34m 3.7s +11d 55m 41.5s 227.814 +49.378
2457821.16 165116.1 0h 34m 2.6s +11d 55m 45.7s 236.618 +45.073
2457821.18 172116.1 0h 34m 1.5s +11d 55m 49.8s 244.293 +40.336
2457821.20 175116.1 0h 34m 0.4s +11d 55m 53.9s 251.092 +35.300
2457821.22 182116.1 0h 33m 59.3s +11d 55m 58.0s 257.241 +30.064
2457821.24 185116.1 0h 33m 58.2s +11d 56m 2.1s 262.921 +24.706
2457821.26 192116.1 0h 33m 57.1s +11d 56m 6.1s 268.285 +19.286
2457821.29 195116.1 0h 33m 55.9s +11d 56m 10.0s 273.455 +13.858
2457821.31 202116.1 0h 33m 54.8s +11d 56m 14.0s 278.538 +8.479
2457821.33 205116.1 0h 33m 53.7s +11d 56m 17.9s 283.628 +3.213
2457821.35 212116.1 0h 33m 52.5s +11d 56m 21.7s 288.812 -2.019
2457821.37 215116.1 0h 33m 51.4s +11d 56m 25.5s 294.172 -7.091
2457821.39 222116.1 0h 33m 50.2s +11d 56m 29.3s 299.789 -11.950
2457821.41 225116.1 0h 33m 49.1s +11d 56m 33.1s 305.741 -16.538
2457821.43 232116.1 0h 33m 47.9s +11d 56m 36.8s 312.103 -20.785
2457821.45 235116.1 0h 33m 46.8s +11d 56m 40.5s 318.937 -24.612
2457821.47 002116.1 0h 33m 45.6s +11d 56m 44.1s 326.282 -27.930
2457821.49 005116.1 0h 33m 44.5s +11d 56m 47.7s 334.145 -30.645
2457821.51 012116.1 0h 33m 43.3s +11d 56m 51.3s 342.478 -32.666
2457821.54 015116.1 0h 33m 42.1s +11d 56m 54.8s 351.174 -33.912
2457821.56 022116.1 0h 33m 40.9s +11d 56m 58.3s 0.068 -34.329
2457821.58 025116.1 0h 33m 39.8s +11d 57m 1.8s 8.960 -33.897
2457821.60 032116.1 0h 33m 38.6s +11d 57m 5.2s 17.651 -32.637
2457821.62 035116.1 0h 33m 37.4s +11d 57m 8.6s 25.976 -30.603
2457821.64 042116.1 0h 33m 36.2s +11d 57m 11.9s 33.830 -27.876
2457821.66 045116.1 0h 33m 35.0s +11d 57m 15.2s 41.167 -24.548
2457821.68 052116.1 0h 33m 33.8s +11d 57m 18.5s 47.991 -20.713
2457821.70 055116.1 0h 33m 32.6s +11d 57m 21.8s 54.345 -16.459
2457821.72 062116.1 0h 33m 31.4s +11d 57m 25.0s 60.290 -11.866
2457821.74 065116.1 0h 33m 30.2s +11d 57m 28.1s 65.901 -7.001
2457821.76 072116.1 0h 33m 29.0s +11d 57m 31.3s 71.256 -1.926
2457821.79 075116.1 0h 33m 27.8s +11d 57m 34.4s 76.436 +3.310
2457821.81 082116.1 0h 33m 26.5s +11d 57m 37.4s 81.524 +8.577
2457821.83 085116.1 0h 33m 25.3s +11d 57m 40.4s 86.606 +13.959
2457821.85 092116.1 0h 33m 24.1s +11d 57m 43.4s 91.777 +19.389
2457821.87 095116.1 0h 33m 22.9s +11d 57m 46.4s 97.142 +24.810
2457821.89 102116.1 0h 33m 21.6s +11d 57m 49.3s 102.827 +30.169
-------------------------------------------------------------------As you can see, the default is to print out the planet's position every 30 minutes for the next 24 hours. The columns in the above table are as follows:
- JD: Julian date for the associated line
- LOCAL: Local time for the associated line (in HHMMSS.S format, based on the system clock of the computer running the program)
- RA: Right ascension of the planet (in hours)
- Dec: Declination of the planet (in degrees)
- Az: Azimuth of the planet (north=0, east=90)
- Alt: Altitude of the planet (degrees above the horizon)
If you wanted instead to know the position of the planet on some other date, you can also supply the date using the --startJD option. For example, if you wanted to know the position starting on the Julian date "2457926.000000" (i.e. June 21, 2017 at 12:00pm UTC) I would have typed:
planetephem --startJD=2457926.0 --planet=2 --longitude=1.444 --latitude=43.605 --elevation=150In this case the information is output at intervals of 30 minutes for 24 hours after the date passed.
I can control the step (via --step) and duration (via --duration) of the printed out information. For example, I can print the information every 5 minutes for 3 hours starting at the specified time via the following command
planetephem --startJD=2457926.0 --step=5 --duration=180 --planet=2 --longitude=1.444 --latitude=43.605 --elevation=150Note that both --step and --duration take their arguments in minutes. The output of the above command is as follows:
= OBSERVER ===================
Longitude: +1d 26m 38.4s
Latitude : +43d 36m 18.0s
Elevation: 150.000000 m
LocalTime: 12:59:60.0
= PLANET =====================
Name : Venus
Mass : 4.868500e+24 kg
Radius: 6051.800000 km
Albedo: 0.650000
JD LOCAL RA DEC Az Alt
=======================================================================
2457926.00 125960.0 2h 54m 20.3s +13d 47m 52.3s 248.666 +39.771
2457926.00 130460.0 2h 54m 20.3s +13d 47m 52.3s 249.792 +38.926
2457926.01 130960.0 2h 54m 21.2s +13d 47m 56.0s 250.897 +38.075
2457926.01 131460.0 2h 54m 22.0s +13d 47m 59.7s 251.982 +37.218
2457926.01 131960.0 2h 54m 22.9s +13d 48m 3.5s 253.048 +36.357
2457926.02 132460.0 2h 54m 23.8s +13d 48m 7.2s 254.096 +35.490
2457926.02 132960.0 2h 54m 24.6s +13d 48m 11.0s 255.128 +34.619
2457926.02 133460.0 2h 54m 25.5s +13d 48m 14.7s 256.143 +33.744
2457926.03 133960.0 2h 54m 26.3s +13d 48m 18.5s 257.143 +32.865
2457926.03 134460.0 2h 54m 27.2s +13d 48m 22.2s 258.129 +31.982
2457926.03 134960.0 2h 54m 28.1s +13d 48m 25.9s 259.101 +31.096
2457926.04 135460.0 2h 54m 28.9s +13d 48m 29.7s 260.061 +30.208
2457926.04 135960.0 2h 54m 29.8s +13d 48m 33.4s 261.009 +29.317
2457926.05 140460.0 2h 54m 30.7s +13d 48m 37.2s 261.946 +28.424
2457926.05 140960.0 2h 54m 31.5s +13d 48m 40.9s 262.872 +27.528
2457926.05 141460.0 2h 54m 32.4s +13d 48m 44.7s 263.789 +26.631
2457926.06 141960.0 2h 54m 33.3s +13d 48m 48.4s 264.696 +25.733
2457926.06 142460.0 2h 54m 34.1s +13d 48m 52.1s 265.595 +24.833
2457926.06 142960.0 2h 54m 35.0s +13d 48m 55.9s 266.486 +23.933
2457926.07 143460.0 2h 54m 35.9s +13d 48m 59.6s 267.370 +23.031
2457926.07 143960.0 2h 54m 36.7s +13d 49m 3.4s 268.247 +22.129
2457926.07 144460.0 2h 54m 37.6s +13d 49m 7.1s 269.118 +21.227
2457926.08 144960.0 2h 54m 38.5s +13d 49m 10.8s 269.984 +20.324
2457926.08 145460.0 2h 54m 39.3s +13d 49m 14.6s 270.844 +19.422
2457926.08 145960.0 2h 54m 40.2s +13d 49m 18.3s 271.700 +18.520
2457926.09 150460.0 2h 54m 41.1s +13d 49m 22.1s 272.552 +17.619
2457926.09 150960.0 2h 54m 41.9s +13d 49m 25.8s 273.400 +16.719
2457926.09 151460.0 2h 54m 42.8s +13d 49m 29.5s 274.246 +15.820
2457926.10 151960.0 2h 54m 43.7s +13d 49m 33.3s 275.088 +14.922
2457926.10 152460.0 2h 54m 44.5s +13d 49m 37.0s 275.929 +14.025
2457926.10 152960.0 2h 54m 45.4s +13d 49m 40.8s 276.767 +13.131
2457926.11 153460.0 2h 54m 46.3s +13d 49m 44.5s 277.605 +12.238
2457926.11 153960.0 2h 54m 47.1s +13d 49m 48.3s 278.442 +11.348
2457926.11 154460.0 2h 54m 48.0s +13d 49m 52.0s 279.278 +10.461
2457926.12 154960.0 2h 54m 48.9s +13d 49m 55.7s 280.114 +9.577
2457926.12 155460.0 2h 54m 49.7s +13d 49m 59.5s 280.950 +8.696
2457926.12 155960.0 2h 54m 50.6s +13d 50m 3.2s 281.787 +7.819
-------------------------------------------------------------------Hopefully you found this useful. If you find any issues while using this script, PLEASE submit an issue. The code is still under development and there are always the possibility of introducing bugs.
© Joshua V. Cardenzana, all rights reserved