Harvest Moon 2020: What’s that Other Dot?

Last weekend, I took a picture of an especially awesome-looking Moon. While the Moon is plenty exciting on its own, I took a picture with my phone because there was another celestial body right above it! You can see my picture below.

At first glance, I believed that Mars was behind the Moon. After staring for a bit, I went back inside, opened Systems Tool Kit (STK), and used STK EOIR to create a synthetic sensor scene of what I just captured with my camera. When I clicked the dot behind the Moon, I was excited to learn that my hunch was correct.

EOIR represents the analog world by digitally sampling the “modeled universe” from a sensor to create a synthetic scene that models 27 optical materials, including:

  • Central bodies
  • Stars
  • Satellites
  • Aircraft
  • Missiles
  • Thermal models, including:
    • Planets
    • Stars
    • Solar radiance
    • Missile plumes

In EOIR, you can expand your scene when you include:

  • Up to 12 independent sensors
  • Custom materials
  • Static or time-dynamic temperature profiles

To confirm your own celestial suspicions, follow the steps below:

  1. Launch STK and create a new scenario with the current date, plus 24 hours.
  2. Insert the Moon and Mars (or another celestial body) into your scenario, and insert a place object with your address.
  3. Insert a sensor on your place object and point it along a vector looking at the Moon, constrained by Zenith.
  4. Create a new 3D Graphics window to look at the Moon from a fixed distance.
  5. Update your EOIR Properties to model your camera phone and environment.
  6. Click the EOIR icon to generate the scene.

While I am certain that many amateur astronomers were already aware of this cool celestial event, I was excited to use STK to solve my mystery.

Good luck using STK to visualize the skies above!



Model electro-optical and infrared sensor performance.

Systems Tool Kit (STK)

Modeling and simulation software for digital mission engineering and systems analysis.