Real-Time Planet Tracker With Laser-Point Accuracy

Space. The final frontier. Unfortunately, the vast majority of us are planet-locked until further notice. If you are dedicated hobbyist astronomer, you probably already have the rough positions of the planets memorized. But what if you want to know them exactly from the comfort of your room and educate yourself at the same time? [Shubham Paul] has gone the extra parsec to build a Real-Time Planet Tracker that calculates their locations using Kepler’s Laws with exacting precision.

An Arduino Mega provides the brains, while 3.5-turn-pan and 180-degree-tilt servos are the brawn. A potentiometer and switch allow for for planet and mode selection, while a GPS module and an optional MPU9250 gyroscope/magnetometer let it know where you are. Finally a laser pointer shows the planet’s location in a closed room. And then there’s code: a lot of code.

The hardware side of things — as [Shubham Paul] clarifies — looks a little unfinished because the focus of the project is the software with the intent to instruct. They have included all the code they wrote for the RTPT, providing a breakdown in each section for those who are looking to build their own.

There is an extra step to auto-align the RTPT to north, otherwise you’ll have to do so manually. But [Shubham Paul] has designed it so that even if you move the tracker about, the RTPT will readjust its calculations in real time. Each part of the project includes a wealth of related information beyond simple instructions to adequately equip any prospective builders.

This hack gets the job done. If it’s looks you’re after, an artistic expression of maker skills and astronomy can be seen in this planetary map that relies on persistence of vision.

24 thoughts on “Real-Time Planet Tracker With Laser-Point Accuracy

      1. @Eric Sorry for the confusion. It won’t be “pin point” accuracy with the hardware I have used (with almost very less “hardware error” correction & no software error correction ). We would require a proper closed loop motor system with auto tuning PID for correcting hardware errors and for software errors there are certain equations that allow you to predict the percentage change in the orbital elements per year. If you include both of them then you can achieve something close to “pin point accuracy”

  1. I have a Meade telescope, fairly low-priced model. Mounted a green lasersight on a picantilly-rail on top of it to align the scope during first setup. Works very well to point the stars used for the alignment.
    But Google’s Skymap for Android works very well to determine which star or planet you’re looking at. Very precise, for free.
    Could mount the phone to the telescope as well, but that would be overkill…

  2. The laws and the equations used in this project are not only for tracking planets but with few modifications and addition of extra database (orbital or osculating elements ) it can also be generalised to track any Celestial Body.

    I have just used a pan or yaw correcting mechanism.One can add a servo to correct the tilt mechanism, then the device can correct itself however it is placed either in yaw, pitch or roll. It can then be a truly “auto correcting planet tracker” and if you mount a telescope on to it then it can automatically find planets and other bodies for you acccurately.

    There are many planet tracking apps, some are free while some are paid but most of them don’t disclose their calculations source code. I have made the source code (& the entire process of making it ) open-source so that enthusiast can find it interesting.

    The most important part is accuracy and that is directly related to error correction. I have done some error correction based on a source but you should implement more error correction.The error correction is important as this project gets older the reference data (of 2013 ) used in this project would give more errors, do you have to implement error correction.See the sources I have mentioned in my website for error correction details.

    1. This is great! Congratulations! And, even more congratulations on making it OpenSource!!! i saw someone here on HackaDay a while back participate in one of the contests with something like this software for solar panel tracking using a Raspberry Pi as well. i got his software but since i didn’t know anything about coding, started “debugging” it on my own Pi. After a while i realized (around line 250 of his 500 line Python program) that i was using Python 3 instead of Python 2. – lol.
      Have a great evening! :)

      1. does the software adjust for the servo dead zone, questionable reputability, compensation for temperature drift in the mechanics, etc? The servos angular error will be magnified on the wall to a very large error (depending on the distance between servo and wall). I understand the use of the laser pointer but using a laser doesn’t change anything about the accuracy of the overall system.

        But seriously, the project idea is very nice. Interesting project.

        1. Yes, the software adjusts for the servo dead zone but not more than that. The mechanical error will of course be amplified (for that we would need a closed loop motor system and PID ,thats why I leave that part to you guys as I have simply used P controller and have focused mainly on planetary calculations).I guess there is a misunderstanding with the name of this post ” Real-Time Planet Tracker with Laser-Point Accuracy” as I didn’t name the post.The laser is not that important (not at all I’ll say) as it just gives a “point” indication which is better than any other light source. The name of my original post in my wordpress site is “Real-Time Planet Tracking System with Trajectory Prediction”

          1. Personally it seems good enough for its use, but I was just a bit annoyed by the people taking that title rather literally instead of the play on words it was intended as – I’m sure.

  3. Very cool. If you’d come up with different software, this would be -extremely- useful in the hobby of visual satellite observation as it could use a green laser to point to or at least near to the spot in the sky where the satellite will appear once it achieves a visible magnitude as it exits the Earth’s shadow so one knows exactly where to look.

    Google: “visual satellite observer’s home page” and “hobbyspace – satellite watching” to read about the potentially zero cost hobby.

    The best dedicated satellite tracking software by far is the freeware Heavensat.

    1. This project can be generalised to track any Celestial Body or Sattelite( artificial or natural) , for that it requires the orbital elements of the particular body( satellite, star etc.) moreover you can just get the “right ascension” and “declination” of the satellite (from Internet) and directly feed it to this system (in case you don’t have the orbital elements) continuously.You don’t have to change the software much.

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