Calculate round-trip radar bounce time from Earth to Moon

[cosinekitty]

Inspired by a conversation on Facebook, I want to create a demo program that calculates the amount of time it takes for a radar pulse from a specific location on the Earth, at a specific date and time, to travel to the Moon and come back to the observer. I will calculate the exact vector from the topocentric observer to the Moon's center, then subtract the mean radius of the Moon. The assumption is that the pulse reflects from the nearest point on the Moon. Divide by the speed of light and multiply by 2 to obtain the round trip time. Extra precision: iterate the calculation to adjust for flight time of the radar pulse!

[cosinekitty]

I am now hosting the first working version of the Moon Radar Bounce Calculator. Here are a couple of feature requests I received from people:

• Also display the distance to the Moon.
• Make it more obvious that the radar bounce is impossible when the Moon is below (or near?) the horizon.
• Calculate Doppler shift (the frequency of the returned signal compared to the transmitted signal)?

[cosinekitty]

A note about Doppler shift testing from Jan Henning Holmedal Lustrup: "If you download WSJT 10 or WSJT-X you can see the amount of real time doppler as a check."