DSLWP – Dwingeloo Radio Telescope

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DSLWP Amateur Radio Team

August 2, 2019

Author(s): Tammo Jan Dijkema

Photo(s): MingChuan Wei (BG2BHC)

A Chinese team from the Harbin Institute of Technology took photos of the moon and earth with a camera linked to an amateur radio transceiver on board of the Chinese DSLWP-B/Longjiang-2 satellite. The DSLWP amateur radio payload flew in orbit around the moon from 21 May 2018 to 31 July 2019. See our blog posts:

Update July 9, 2020
The results of this Chinese lunar satellite have now been published in Nature Communications. Tammo Jan Dijkema and Cees Bassa were involved in this publication. They are included in the publication as affiliated with “C.A. Muller Radio Astronomy Station “and” ASTRON “. See https://www.nature.com/articles/s41467-020-17272-8 (‘open access’). A short text about the beautiful moon photos was published before in Science, but this is a full publication. Of course the Dwingeloo Radio Telescope is mentioned in the article.
The hopefully complete list of contributors to this mission, together with all (open) data, has also been officially published and is available on https://doi.org/10.5281/zenodo.3571330 referred to in the Nature Communications article. The full list also includes quite a few CAMRAS volunteers.

Many people worked together on the realization of this DSLWP amateur radio mission:

Harbin Institute of Technology (BY2HIT)
Wei Mingchuan (BG2BHC), Hu Chaoran (BG2CRY), Tai Mier (KG5TEP), Zhao Yuhao (BG2DGR), Huang Jiahe, Han Yongbo (BG2CYR), Wang Hongxu, Zhang Jiyao, Guo Qing (BG2DGG), Pei Le (BG2CSF), Wang Xizi, Su Yusen, Miao Yue, Wang Cheng, Cao Mengyu (BG2CYQ), Yang Pan, Zhao Hao, Wang Tianci (BG2EBZ), Li Yutong, Li Jiqing

CAMRAS Dwingeloo Radio Telescope (PI9CAM)
Cees Bassa, Tammo Jan Dijkema, Paul Boven (PE1NUT), Jan van Muijlwijk (PA3FXB), Harry Keizer (PE1CHQ), André Offringa, Jishnu Nambissan (VU3VWB), Simon Bijlsma (PA7SB), Pieter-Tjerk de Boer (PA3FWM), Vanessa Moss, Ard Hartsuijker, Sigrid Witteveen

Kansai EME Enthusiasts at Wakayama
Ishihara Masaji (JH3BUM), Kishiura Kazuki (JH3NYP), Morita Katsumi (JA3RVS), Akiyama Hiroaki, Ma Jizhuang (BG2KAJ), )

Chinese Radio Amateurs Club

Beijing Aerospace Flight Control Center

State Radio Monitoring Center

National Astronomical Observatory of China

Amateur Radio Club Of The 1st Primary School Of Tongfuzhong Road, Guangzhou (BY7KTO)

Amateur Radio Ground Station Club of the FH Aachen University of Applied Sciences (DL0FHA)
David Rénée Krieger, Gabriel Möbius, Sacha Joseph Tholl

Independent contributors
Reinhard Kühn (DK5LA), Daniel Estevez (EA4GPZ), Zhang Jianhua (BA7KW), Liang Tiewei (BA7NQ), Zhu ShaoHua (BD4SY), Li Changhai (BG2AGN), Edson Pereira (PY2SDR), Robert Mattaliano (N6RFM), Nico Donoso (CD3NDC), Roland Marcel Zurmely (PY4ZBZ), Flávio Arcangelo (PY2ZX), Jean Marc Momple (3B8DU), Patrice Momplé (3B8FA), Dimitry Borzenko (4Z5CP), Wang Qi (BD9BU), Jiang Lei (BG6LQV), BG8IXQ, Mike Rupprecht (DK3WN), Dave Dibley (G4RGK), Lucio Perrone (I0LYL), Rocco Labella (IK8XLD), William (ViIU2EFA), Ferruccio Paglia (IW1DTU), JA0CAW, JA1HCB, JA1OGZ, JA5BLZ, JE1CVL, Scott Chapman (K4KDR), Drew Glasbrenner (KO4MA), Fernando Costarelli (LU1HKO), Maximiliano A. Bravo (LU3DMB), Victor Velez (LU5EWR), Carlos Guillermo Vahnovan (LU8DQ), Dr Chris Bridges (M0IEB), Richard (M0VKK), Lars Petersen (OZ1BXM), Nico Janssen (PA0DLO), Albert van Deursen (PD0OXW), Peter (SP5ULN), Olgierd Pilarczyk (SQ3SWF), Micha Zawada (SQ5KTM), Joe Pereira (VK5EI), Mark Jessop (VK5QI), Rocco Valenzano (W2RTV), Imants Tukleris (YL3CT)

Dwingeloo sends heart beat Neil Armstrong back to the Moon

July 19, 2019

Author(s): Tammo Jan Dijkema, Jan van Muijlwijk, Harry Keizer; Translation: Ard Hartsuijker

Photo(s): see below blog post

When on 20 and 21 July everyone is looking back on the 50 year Moon landing anniversary, CAMRAS volunteers (in particular Harry Keizer and Jan van Muijlwijk) are working hard in the Dwingeloo Radio Telescope.

In the night of 20 to 21 July 2019, exactly 50 years after the Moon landing, they will bounce radio waves off the surface of the Moon, and catch their reflection (moon bounce). The radio telescope will be used for this from about Saturday 20 23:00 UTC to Sunday 21 06:30 UTC.

Other dishes, even small ones, can also receive the moon echos. A bigger dish that will listen in part of the time is the Mark II telescope of Jodrell Bank Observatory near Manchester. This weekend it hosts the Blue Dot festival; the Moon echos will be played live on the festival.

: Dwingeloo Radio Telescope

: Mark II telescope in Jodrell Bank.

Early in the morning, at 02:56 UTC, it is exactly 50 years ago that Neil Armstrong set foot on the Moon. While he did this, his heart beat was recorded. Now 50 years later, the Dwingeloo telescope will send this heartbeat back to the Moon, as part of the art project “Giant step” of artist Richard Clar. He translated the heart beat to audio, adding in the famous words “That’s one small step for [a] man, one giant leap for mankind”.

Other sounds that Dwingeloo will moon bounce are the things that kids (and grown-ups) would say when they would set foot on the Moon. These sentences were recorded by artist Martine-Nicole Rojina in her ‘First Steps’-project.

Even more, the CAMRAS radio amateurs will send pictures to the moon using ‘visual moonbounce’, a technique similar to fax.

At the end of the morning, from 05:30 – 07:30 UTC, the telescope will download images off the Chinese satellite in Lunar orbit.

All these activities will take place between Sat 23:00 UTC and Sun 7:30 UTC. During these hours the telescope is not open to the public. Sending the sounds can be followed via webradio radioerevan.airtime.pro.

The telescope is open to the public on Sunday 21 July 2019 from 11:30 tot 14:00 UTC (13:30 – 16:00 local Dwingeloo time). See Zomerse zondagmiddagopening 2019 (in Dutch) for details. The Moon will not be above the horizon then, but we will of course pay special attention to it.

Planned times (in Dwingeloo local time, CEST)

Blue Dot: 02:15 – 03:00
04:56 sonified heart beat Neil Armstrong
Blue Dot: 05:00 – 07:30
Chinese Lunar satellite DSLWP-B: 7:30 – 9:30 uur

Photos: Boot and bootprint in lunar soil (NASA; Apollo Archive Project), Dwingeloo Radio Telescope (Harry Keizer; CAMRAS), Mark II telescope (Mike Peel; Jodrell Bank Centre for Astrophysics, University of Manchester)

Photo solar eclipse from Chinese lunar satellite

July 4, 2019

Author(s): CAMRAS-DSLWP-B team; Translation: Ard Hartsuijker

Photo(s): CC-BY-4.0 DSLWP Amateur Radio Team

Last Wednesday morning, July 3, the Dwingeloo Radio Telescope downloaded this eclipse photo from the Chinese lunar satellite DSLWP-B. The photo was taken on Tuesday evening, July 2, 2019, when a full solar eclipse was seen in South America. That is where the shadow of the Moon fell on Earth. That shadow is clearly visible in the photo.

The ISS and weather satellites have previously taken pictures of the shadow of the Moon on Earth, but this picture is – as far as we can ascertain – the first ever photograph of a solar eclipse taken from an orbit around the Moon. And the Dwingeloo Radio Telescope cooperated!

This year and last year many CAMRAS volunteers contributed to the collaboration in this special satellite webcam project from MingChuan Wei (BG2BHC/BY2HIT) of the Harbin Institute of Technology. A project that will end in the course of this month as the DSLWP-B satellite will crash onto the Moon in a controlled manner.

The CAMRAS-DSLWP-B team consisted of Cees Bassa, Paul Boven (PE1NUT), Tammo Jan Dijkema, Harry Keizer (PE1CHQ), Jan van Muijlwijk (PA3FXB) and André Offringa. Pieter-Tjerk de Boer (PA3FWM) and Simon Bijlsma (PA7SB) enabled streaming over WebSDR; Michel Roelofs (PA1MEF) made it possible to share raw data. In a broader scope, the team consists of the team at Harbin, specifically MingChuan Wei, and Reinhard Kühn (DK5LA) for uplink and Daniel Estévez (EA4GPZ/M0HXM) for analyses of the satellite orbit.

More info about this project in our blog posts Our precious Earth and the lunar far side, Time-laps of the Earth appearing behind the Moon and New photo of Lunar farside and Earth. Also, see our guest blog on The Planetary Society.

The moon and earth photos in this blog post are licensed under a Creative Commons Attribution 4.0 International License.
When using the photos, state “Photo: CC-BY-4.0 DSLWP Amateur Radio Team“.

(Participants DSLWP Amateur Radio Team)

New photo of Lunar farside and Earth

February 5, 2019

Author(s): Cees Bassa, Tammo Jan Dijkema, Vanessa Moss; Translation: Ard Hartsuijker

Photo(s): CC-BY-4.0 DSLWP Amateur Radio Team

On Monday 4th February 2019, the Dwingeloo telescope downloaded a new photo of Earth and the lunar farside. This photo, taken Sunday 3rd February 2019 at 15:20 UTC, shows the lunar farside and Earth (with South America in view). The lunar farside has more visible craters than the side of the Moon which faces Earth.

This photo was taken by the Chinese satellite LongJiang 2 in a lunar orbit. One of the devices on this satellite was made by students from the Chinese Harbin Institute of Technology. They put a (relatively) simple webcam on it that can take pictures on command. These photos are then sent to Earth with a little antenna. Because the satellite is so far away, receiving the signal requires a large radio antenna. The Chinese have asked the CAMRAS volunteers at the Dwingeloo Radio Telescope to help with this. Downloading this photo from the satellite to the Dwingeloo Telescope (16 KB in size) took 20 minutes.

The little Chinese satellite that took this photo has been in lunar orbit since the beginning of 2018. It ‘took a ride’ on the rocket that launched the bigger QueQiao satellite. That satellite also hosts antennas from ASTRON, the original owner and professional neighbour of the Dwingeloo Radio Telescope. ASTRON hopes to use the antennas on the big satellite to receive signals from just after the Big Bang as part of the Netherlands-China Low-frequency Explorer (NCLE) project.

The amateur radio payload that took this picture was developed at the Harbin Institute of Technology by Mingchuan Wei (BG2BHC), Hu Chaoran (BG2CRY), Tai Mier (KG5TEP), Zhao Yuhao (BG2DGR). Taking this photo was coordinated by Wei. While downloading this picture, the CAMRAS Dwingeloo Radio Telescope was operated by Cees Bassa, Tammo Jan Dijkema and Vanessa Moss. The commands were uplinked to the satellite by German radio amateur Reinhard Kuehn (DK5LA) with his home-built yagi array. See more details in blog post Our precious Earth and the lunar far side.

The photo has been color-corrected. Since the satellite camera lacks an infrared filter, colors come out too red. The original is below; we edited it to balance the colors, and make the Moon greyscale.

In October 2018, the Dwingeloo Telescope also cooperated in receiving a lunar farside photo (see blog post Our precious Earth and the lunar far side) and even a time-lapse showing the Earth disappear behind the Moon (see blog post Time-laps of the Earth appearing behind the Moon). At that time, the satellite was closer to the Moon, so the entire Moon did not fit in the picture. In the next months, we expect to receive more of these photos. But in August 2019, this adventure will end: then LongJiang 2 will crash in a controlled manner onto the lunar surface in a controlled manner. QueQiao will continue operating for the foreseeable future.

(Participants DSLWP Amateur Radio Team)

Possibilities of the CAMRAS webSDR

January 30, 2019

Author(s): Simon Bijlsma (PA7SB)

Photo(s): CAMRAS Simon Bijlsma, CC-BY-4.0 DSLWP Amateur Radio Team

Observing meteors

During our special openings and stargazing evenings, dozens of visitors are interested in observing meteors. This is why CAMRAS volunteers Simon Bijlsma (PA7SB) and Frans de Jong (PE1RXJ) have put more information on the astronomy page for those who want to read it again or want to know more. It concerns four articles:

Antenna building
Observing meteors with radio
Visualize radio meteors
Software Defined Radio receiver

We previously wrote those articles in Dutch for the website of the KNVWS Working Group Meteors. The articles are about observing meteor scatter with a self-built antenna in combination with an RTL SDR dongle and suitable software and visualizing and counting meteors with the SpectrumLab program. The aforementioned articles are here on the CAMRAS website in both Dutch and English,

Who is not such a self-builder or lacks the time needed to build a meteor scatter receiving station can of course also use our online CAMRAS webSDR receiver that is specially designed to receive real time meteor scatter with your own tablet, laptop, smartphone or computer.

CAMRAS volunteer Pieter-Tjerk de Boer (PA3FWM) designed this beautiful webSDR software already ten years ago. At the Amateur Radioclub of the University of Twente, his own UT webSDR receiver runs for the entire short wave spectrum from 0.1 to 30 MHz.

The CAMRAS webSDR for receiving meteor reflections was set up after a successful experiment in 2011 in which we streamed live meteor reflections over the internet for the first time during the maximum of the Perseids meteor shower. As a result, Simon Bijlsma has built the 2-meter and 6-meter Yagi antennae that are now used for the CAMRAS webSDR. The building description can be found in article 1. These antennae are linked to two RTL SDR dongles which then provide the CAMRAS webSDR stream with the help of the SDR software.

With the webSDR tuning to the frequency of the French Space radar GRAVES gives the possibility to observe aircraft and the ISS in addition to meteor reflections. Even echoes of the GRAVES radar that are reflected by the Moon are regularly seen! The distance to the Moon back and forth is about 800,000 km and the Moon is also a very bad reflector for radio waves, so most of the signal is lost. Nevertheless, the echoes are so strong that they can be clearly seen on the webSDR receiver. See above image with meteors (hook-shaped), aircraft (lines in the middle), ISS (slanted dotted line) and the moon (vertical dotted line).

Observing satellites

Recently, the webSDR has been expanded with a receiver for a Chinese moon satellite. The Dwingeloo telescope is one of the official reception ground stations for the Chinese moon satellite DSLWP-B. From Germany the uplink command signals are sent to the satellite. This satellite floats in an elliptical orbit around the moon, through which the satellite can also take pictures of the back of the moon. This is not possible from the earth. However, the nominal transmit power of this satellite is very limited and, depending on the mode used, only 1 to 2 Watt (30 – 33 dBm).

The 25m Dwingeloo telescope is used to receive the lunar photos and telemetry signals, the frequencies used in the 70cm band are 435.4 MHz and 436.4 MHz. The beautiful photos (see above) of the back of the moon and the earth can be found elsewhere on this website. Worldwide there is great interest among radio amateurs for the photos and telemetry signals of this satellite. In collaboration with Pieter Tjerk de Boer, Simon Bijlsma therefore connected a third RTL SDR dongle and connected it to the 70cm antenna of the telescope. This allows our many (international) visitors to the webSDR to follow the satellite signals in real time and decode the GMSK and FT4G signals themselves when the telescope follows the satellite.

Time-laps of the Earth appearing behind the Moon

November 14, 2018

Author(s): Tammo Jan Dijkema, Cees Bassa, Paul Boven (PE1NUT); Translation: Ard Hartsuijker

Photo/video: CC-BY-4.0 DSLWP Amateur Radio Team

On October 7, 2018, the Chinese lunar satellite DSLWP-B made this 1.5 hour time-lapse of the Earth appearing behind the Moon. An international team of radio amateurs and amateur astronomers downloaded the images with the Dwingeloo Radio Telescope. The team consisted of MingChuan Wei (BG2BHC), Reinhard Kuehn (DK5LA), Daniel Estévez (EA4GPZ/M0HXM), Tammo Jan Dijkema, Cees Bassa, Paul Boven (PE1NUT) and even more team members were involved. Click on the picture to see the time-lapse.

Tammo Jan Dijkema gave a short explanation about this project in the Dwingeloo Radio Telescope for the local TV station RtvDrenthe Dwingeloo-telescoop ontvangt maanfoto’s (in Dutch).

For more info about this project see our earlier blog Our precious Earth and the lunar far side.

The moon and earth photo and video in this blog post is licensed under a Creative Commons Attribution 4.0 International License.
When using the photo and/or video, state “Photo/video: CC-BY-4.0 DSLWP Amateur Radio Team“.

(Participants DSLWP Amateur Radio Team)

Our precious Earth and the lunar far side

October 12, 2018

Author(s): Cees Bassa, Tammo Jan Dijkema; Translation: Ard Hartsuijker

Photo(s): CAMRAS Tammo Jan Dijkema, Harry Keizer. Moon and Earth-images: CC-BY-4.0 DSLWP Amateur Radio Team

Far side of the Moon photographed by amateurs

This image shows the far side of the Moon, as well as our own planet Earth. It was taken with a camera linked to an amateur radio transceiver on board the Chinese DSLWP-B / Longjiang-2 satellite (call sign BJ1SN), 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 build the radio transceiver on board 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 transmissions, as well as the JT4G modulation
scheme designed by radio amateur and Nobel prize winning astrophysicist Joe Taylor (K1JT) for weak signal Moon bounce 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 on board 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.

This full color adjusted image is received by radio amateurs, including the radio amateurs of the Dwingeloo Radio Telescope (PI9CAM) operated by Tammo Jan Dijkema and myself. Commands were created by MingChuan Wei (BG2BHC) and uplinked by Reinhard Kuehn (DK5LA). The color correction of the image is done by Wei.

The annotated picture with names of Moon craters is made by Tammo Jan. Note that the crater Minnaert is named after the Dutch astronomer Marcel Minnaert. Minnaert was member of the SRZM board in the time the Dwingeloo Radio Telescope was designed and build.

Addendum after October 12, 2018

Below are two other images, also slightly color corrected. The original images are here. The third image shows the Moon clearly seen from Dwingeloo Radio Telescope through the window of the observation room and the metal mesh of the mirror.

The animation below shows the Moon as seen from the DSLWP-B satellite as it orbits around the Moon. The animation pictures were taken on October 15. Data for the animation was collected by Cees Bassa and Tammo Jan Dijkema in the Dwingeloo Telescope (PI9CAM), by Imants Tukleris (YL3CT), Mike Rupprecht (DK3WN), and Dimitry Borzenko (4Z5CP). The satellite was commanded by Reinhard Kuehn (DK5LA).

About this experiment, Cees Bassa and Tammo Jan Dijkema wrote a slightly more detailed blog Imaging the Earth from Lunar orbit in The Planetary Society.

Find more recent technical info at Twitter @PI9CAM.

A more recent animation is on our newer blog Time-lapse of the Earth appearing behind the Moon.

Update February 4, 2019

After a radio-quiet period to avoid interfering with the Chang’e 4 Lunar landing, DSLWP-B became active again on 13 January 2019. The first opportunity to take photos of Earth and Moon were on 3 February, on which a command was sent to take another timelapse. The first image from this timelapse was downloaded with the Dwingeloo telescope on February 4, 2019. For the first time, it the entire Moon and Earth are in view.

Update July 9, 2020

The results of this Chinese lunar satellite have now been published in Nature Communications. Tammo Jan Dijkema and Cees Bassa were involved in this publication. They are included in the publication as affiliated with “C.A. Muller Radio Astronomy Station “and” ASTRON “. See https://www.nature.com/articles/s41467-020-17272-8 (‘open access’). A short text about the beautiful moon photos was published before in Science, but this is a full publication. Of course the Dwingeloo Radio Telescope is mentioned in the article.

In advance in December 2017

December 2017, in preparation for the mission and discussion of the possibilities of the antennas and receivers in the radio telescope, Hu Chaoran (BG2CRY) and MingChuan Wei (BG2BHC) both of the Harbin Institute of Technology visited Harry Keizer (PE1CHQ) and Jan van Muijlwijk (PA3FXB) of CAMRAS. On the photo in front of the Dwingeloo Radio Telescope to the left Jan, in the middle Chaoran, and to the right Wei. In fact the Dwingeloo dish is transparent metal mesh, but on this winter photo covered with snow.

(Participants DSLWP Amateur Radio Team)