Most of the world Wi-Fi usage operates around the 2.4 GHz band (allocated spectrum). That means our telescopes have to cut that portion of the band out when doing #RadioAstronomy Tommy from our team has tested some mitigation methods and found we can use 90% of this band! arxiv.org/abs/2605.30761

CCSDS 8192-bits CADUs, RSS 223/255 I=4

We're still tracking #Artemis II with the Dwingeloo radio telescope, with four very enthousiastic amateurs staying up all night in the control room. We just witnessed the Orion upper stage separation burn in our doppler tracking.

A first view on Artemis II from South America on 2026-04-02, 01:57:58 UTC

We are tracking #Artemis II with the historic Dwingeloo radio telescope. In the doppler shift of the carrier signal we see the manual manoevers that the astronauts perform while flying formation with the upper stage.

We have AOS from #Artemis II!

The #fireball of 8 March was captured on camera by DAARO! on the roof of ASTRON.

What is the origin of 1LHAASO J0343+5254u? by @hen_edler, @itsMariaArias, myself, @cbassa.bsky.social Our multi-band analysis suggests that the PWN candidate previously proposed to be its origin is actually an obscured galaxy cluster, unrelated to the LHAASO emission arxiv.org/abs/2603.03164

It still seems unreal to me that humans will soon be flying back to the moon! They will be returning to Earth at a speed of 40.000 km/h, the fastest ever reentry of a crewed spacecraft. This remastered video shows a similar reentry from the #Artemis 1 mission back in 2022 at 9x speed. 🔭🧪

Great aurora visible in Dwingeloo yesterday!

An absolutely awesome display of Northern Lights over the Netherlands during the past hour! Red glow in the North and a green curtain passing over whose motion was very obvious with the naked eye. This is 1 hour worth of 15 second exposures with my all sky camera from 21to 22UTC. #auroraBorealis

Picking up the old hobby of catching radio signals from newly launched satellites. These are 5 satellites from the Space X launch that happened less than 3 hours ago. Signals from 4 CONNECTA IOT satellites on 401.5MHz and 2240MHz, as well as CarbSAR at 2243.333MHz.

Last Thursday, a group of European radio telescopes (HyperFlash / ÉCLAT) detected a flash from the repeating Fast Radio Burst discovered end of December. We also detected this burst! Our detection came in too late to be included in the telegram, but here it is! www.astronomerstelegram.org?read=17588

Snow in Dwingeloo. #bluesky

Since posting this 2025 year-long keogram, there have been quite a few questions asking how it was created and what is visible. In this thread I'll try to explain how it all works.

I put together a mosaic of 2025 from the timelapse camera on my roof jwheare.com/year-mosaic/... (not a keogram, but inspired by @cbassa.bsky.social)

Happy new year! My all sky camera imaged the sky every 15 seconds and this picture shows what happened in the sky in 2025. It shows the length of the night and day with the hourglass shape, the monthly lunar cycle with the diagonal bands, the elevation of the Sun at local noon, and lots of clouds.

It's cleared up in Sydney and I can see the shadow creeping across the Moon! 🥳🌚🔭

💥Greater (partial) success for #amateurradio and #amsat satellite operators in dispute with AST Spacemobile over commercial use of the 430-440 MHz amateur radio band for TT&C! 💥 In its reference Attachment to the recent grant, dated August 29, 2025, the FCC imposes clear limits ⬇️

NOAA-15 was decommissioned today at 15:26 UTC, with its AVHRR/3 Instrument still in better state than the last 2 remaining on MetOp-B & C. It wouldn't be so disappointing if this wasn't done for the wrong reasons... Makes you wonder what happened to NOAA.

#skao2025 Federico Di Vruno on impact of satellites on #RadioAstronomy from intended emissions (strong enough to saturate receivers) & unintended electromagnetic radiation (originating from on satellite electronics). In future 🛰️ constellations could impact 25% of our observing time! 🔭📡🧪

New paper day! In 'Near-future rocket launches could slow ozone recovery', we show that scaling up use of launch vehicles 🚀 has a point where the healing of the ozone layer is affected 🧪🛰️ Open access, free to read & share

Here, strf was used by the UVSQSat-NG team : - at the beginning of the mission to optimize the preliminary TLEs so that the university could establish the most reliable communication possible, - for monitoring purposes since refined TLEs have become available... Thank you for the great work!

Unfortunately the surface of the Moon is also quite hard.

We lost HAKUTO-R M2 signal suddenly

We have lost signal of Hakuto-R M2 Resilience! We saw the signal and its Lunar reflection close to each other before LOS, indicating that it was very close to the surface when the signal disappeared. Space is hard!

We are now tracking the landing attempt of #Hakuto-R Mission 2 #Resilience. Check our livestream at www.youtube.com/live/C7-MQ2U...

On the occasion of the @unesco.org International Day of Light, we created a 'light painting' using the Dwingeloo Telescope by mounting a light bulb at the focus for half an hour. #lightday2025 @idlofficial.bsky.social

And Magritte fans 😀

Two days too late and perhaps only funny for those speaking Dutch. (H/T Gemma Janssen.)

Maybe the upper stage failure ended up tumbling the spacecraft fast enough to break it up?

Following up on @marcolangbroek.bsky.social 's post on the upcoming Venera capsule reentry, I've done a writeup describing my own analysis of this object, which I first got interested in a quarter century ago! planet4589.org/space/debris...

Time for some science again... We are finding new pulsars with CHIME by stacking data over multiple days to boost sensitivity. As always, a huge effort by multiple postdocs, students and programmers. arxiv.org/abs/2504.16293

After fixing this mistake, the frequency difference is on the order of 1 Hz. This is about 0.7 ppb, so it is within the accuracy that we could expect for the GPSDO at Bochum. So mystery solved!

Great work! This is why we put our IQ on the web :) One remark on why Dwingeloo is less sensitive: we have a relay in front of the first LNA, because Dwingeloo also transmits in experiments like this one. Apart from that, we may also need a better LNA.

The signal can be detected both in the Dwingeloo and Stockert 25 m radio telescopes, but the performance of Dwingeloo is poorer. The observed Doppler spread is on the order of ±0.75 Hz, which is a bit less than the spread model I made. Read more: destevez.net/2025/04/anal...

New blog post: Analysis of the CAMRAS Venus radar experiment. A deep dive into the Earth-Venus-Earth L-band radar experiment done in March by @radiotelescoop.bsky.social, Astropeiler Stockert, the Deep Space Exploration Society, and Open Research Institute. 🧵

Oh dear ... "Mr Eclipse" Fred Espenak just wrote this on a mailing list and on facebook.com/fred.espenak.... The eclipse scene has lost so many of its greatest in the last three years, Jay Pasachof, Serge Kouchmy, Glenn Schneider, and now its towering figure will leave us. :-(

A bit late, but here is some additional analysis of the Earth-Venus-Earth radar experiments with @radiotelescoop.bsky.social from March 22nd, 2025. It takes the 4 recordings at the Dwingeloo and Stockert telescopes and searches in Doppler frequency and Doppler rates for the radar reflections.

Just catching up on this excellent #RadioAstronomy work by ProAm group using the Dwingeloo Telescope. 🔭📡 They managed to fire a signal at Venus, and catch the reflection back on two antennas here on Earth! There is *lots* of nice working coming from this group! 👏👏👏 Blog + link to script below

Start of the occultation of the #Pleiades by the #Moon tonight. The Moon setting behind trees. @leonoor.bsky.social @johanklos.bsky.social @waddensky.nl

This video shows the Moon occulting several stars from the Pleiades star cluster (M45) earlier this evening. The 40 minute observing run is condensed into 40 seconds. The brightest star is Merope (23 Tau) at magnitude 4.2. Now to work through 20GB of timestamped images to extract occultation times.

Some how I completely missed the fact that the Moon was going to occult several of the stars in the Pleiades. I managed to quickly put together a CMOS camera and a 300mm lens to capture the motion of the Moon across these stars at 10fps. Here's the occultation of the 8th magnitude star HD23361.

Hier is een (niet-versnelde) video waarin Electra, één van de helderste sterren van de #Plejaden, in een fractie van een seconde achter de #Maan verdwijnt (merci, @frankdeboosere.bsky.social, om hier de aandacht op te vestigen!).

Certainly an interesting description of the NROL-69 payload... So we expect this satellite to maneuver, possibly lots.... source: www.nro.gov/Portals/135/...

Successful Earth-Venus-Earth Amateur Communications: https://openresearchins.micro.blog/2025/03/24/successful-earthvenusearth-amateur-communications.html

This was quite the project to have been involved in (if only minor). Thanks to @telkamp.eu and other volunteers at @radiotelescoop.bsky.social for doing the heavy lifting to make this extremely cool experiment possible!