Measuring the speed of light and the moon distance with an occultation of Mars by the Moon

a Citizen Astronomy Campaign

Zuluaga et al
In July 5th 2014 an occultation of Mars by the Moon was visible in South America.
Citizen scientists and professional astronomers in Colombia, Venezuela and Chile performed a set of simple observations of the phenomenon aimed to measure the speed of light and lunar distance.
This initiative is part of the so called “Aristarchus Campaign”, a citizen astronomy project aimed to reproduce observations and measurements made by astronomers of the past.
Participants in the campaign used simple astronomical instruments (binoculars or small telescopes) and other electronic gadgets (cell-phones and digital cameras) to measure occultation times and to take high resolution videos and pictures.
In this paper we describe the results of the Aristarchus Campaign.
We compiled 9 sets of observations from sites separated by distances as large as 2,500 km. We achieve at measuring the speed of light in vacuum and lunar distance with uncertainties of few percent.
The goal of the Aristarchus Campaigns is not to provide improved values of well-known astronomical and physical quantities, but to demonstrate how the public could be engaged in scientific endeavors using simple instrumentation and readily available technological devices.
These initiatives could benefit amateur communities in developing countries increasing their awareness towards their actual capabilities for collaboratively obtaining useful astronomical data.
This kind of exercises would prepare them for facing future and more advanced observational campaigns where their role could be crucial.
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Flash from Curiosity Rover’s Laser Hitting a Martian Rock

The sparks that appear on the baseball-sized rock (starting at :17) result from the laser of the ChemCam instrument on NASA’s Curiosity Mars rover hitting the rock.
ChemCam’s laser zapping of this particular rock was the first time the team used Curiosity’s arm-mounted Mars Hand Lens Imager (MAHLI) camera to try and capture images of the spark generated by the laser hitting a rock on Mars. Their efforts were a success.
The video is compiled from single images from the MAHLI camera, taken during the 687th Martian day, or sol, of Curiosity’s work on Mars (July 12, 2014).

Since Curiosity landed in Mars’ Gale Crater in August 2012, researchers have used ChemCam’s laser and spectrometers to examine more than 600 rock or soil targets. The laser itself has been fired more than 150,000 times. The process, called laser-induced breakdown spectroscopy, hits a target with pulses from the laser to generate sparks, whose spectra provide information about which chemical elements are in the target. Multiple laser shots are fired in sequence, each blasting away a thin layer of material so that the following shot examines a slightly deeper layer. In this case, “Nova” displayed an increasing concentration of aluminum as a series of laser shots from the rover penetrated through dust on the rock’s surface.