Daily Image

16-10-2018
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The Earth and the far side of the Moon

Submitter: Cees Bassa & Tammo Jan Dijkema
Description: This image shows our own planet Earth, as well as the far side of the Moon. The image was taken with a camera linked to an amateur radio transceiver onboard the Chinese Longjiang-2 satellite, currently in orbit around the Moon, and transmitted back to Earth where it was received with the Dwingeloo telescope.

This image represents the culmination of several observing sessions spread over the past few months where we used the Dwingeloo telescope in collaboration with the Chinese team from Harbin University of Technology, who built the radio transceiver onboard Longjiang-2, and radio amateurs spread across the globe. During these sessions we tested receiving telemetry through low-bit rate and error-resistant digitally modulated GMSK transmissions, as well as the JT4G modulation scheme designed by Nobel prize winning astrophysicist Joe Taylor for weak signal Moonbounce experiments. Besides telemetry, we performed a VLBI experiment by simultaneously observing Longjiang-2 from China and Dwingeloo, and also downloaded images taken by Longjiang-2 of the lunar surface, lens flares, and the starry sky as seen from lunar orbit.

The transceiver onboard Longjiang-2 was designed to allow radio amateurs to downlink telemetry and relay messages through a satellite in lunar orbit, as well as command it to take and downlink images. In that it has succeeded, as many radio amateurs have received telemetry and image data. Being able to use the Dwingeloo telescope to help with this has been a lot of fun.
Copyright: MingChuan Wei, Harbin Institute of Technology
 
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