Northern Light above Averbode

As I was still sick and dragging myself towards bed, I checked one more time my iPhone and saw about 50 messages... when opening the first message it was clear... there was northern light visible. I took my iPhone and Nikon and yes... red and green colors in the sky.

Listening to the early Universe - Studium General Marc Klein Wolt

Selfie with Dr. Marc Klein Wolt

I attended the lecture by Dr. Marc Klein Wolt which spoke of his mission to the back side of the Moon and his ideas about installing huge antenna's on the back side of the Moon.

Dr. Marc Klein Wolt, astrophysicist at Radboud University Nijmegen and director of the Radboud Radio Lab, is exploring the origin of the Universe by studying the redshifted 21-centimeter hydrogen line. This signal, emitted by neutral hydrogen, allows scientists to probe the so-called Cosmic Dark Ages, the era after the Big Bang and before the first stars and galaxies ignited.

As the Universe expanded, the original 21-cm signal was stretched, or redshifted, to much longer radio wavelengths (100m and more). Detecting this extremely faint radiation from Earth is nearly impossible due to radio interference and the blocking effects of Earth’s ionosphere. Therefor the idea to install equipment at the back side of the Moon.

In 2019, a radio antenna developed by Klein Wolt’s team flew with the Chinese Chang’e-4 mission, using the Queqiao relay satellite positioned behind the Moon. This location, permanently shielded from Earth’s radio noise, offers one of the quietest environments in the Solar System for radio astronomy.

By observing from lunar orbit, Klein Wolt aims to trace how the first cosmic structures formed from primordial hydrogen. His long-term vision includes building radio antennas on the lunar surface itself. These plans align with future European Space Agency (ESA) lunar initiatives, in which Europe seeks a scientific presence on and around the Moon.

The scientific importance of the 21-cm line is underscored by its inclusion on the Voyager Golden Record, sent into interstellar space as a universal cosmic reference. Together, lunar radio astronomy and international missions may soon reveal how darkness in the early Universe gave way to the first light.

The cosmic microwave background (CMB) was released about 380,000 years after the Big Bang during recombination, when electrons and protons combined to form neutral hydrogen. This was the first light that could travel freely through the universe. After that came the cosmic dark ages (roughly 380,000 to 100 million years), when the universe was mostly neutral hydrogen and no stars had formed yet. During this period, the 21 cm line from neutral hydrogen can be used to trace the distribution of matter. Later, the first stars and galaxies formed (~100–400 million years), emitting ultraviolet light that ionized hydrogen, beginning the reionization process, which was largely complete by about 1 billion years, weakening the 21 cm signal in ionized regions.

PRO-AM Collaboration for Systematic Solar Observations

 

PRO-AM Group | JASON2025

Systematic observations of the solar chromosphere and photosphere began 117 years ago at the Meudon Observatory with the spectroheliograph developed by Deslandres. Since then, an exceptional collection of more than 90,000 monochromatic images in Ca II K and Hα has been built up, covering over 11 solar cycles. This unique dataset is made available to the international scientific community through the BASS2000 database.

In 2023, this long observational tradition received new momentum with the launch of a “PRO-AM” collaboration between professional and amateur astronomers. This initiative makes use of the Solar Explorer (Sol’Ex), a compact, high-quality spectroheliograph designed by Christian Buil. The aim of the collaboration is to record solar images on a daily basis, and whenever possible several times per day. Thanks to dozens of observing stations distributed across different geographical locations, the impact of local weather conditions is significantly reduced.

Meanwhile, the range of available spectroheliographs has been further expanded. In addition to the original Sol’Ex, Sol’Ex Pro, Sol’Ex V2, Sol’Ex by James R, Sol’Ex original, and the SHG700 are now available, enabling amateurs with diverse technical backgrounds and resources to participate in the project.

In 2025, a total of 59 amateur astronomers were actively involved in the PRO-AM collaboration. The majority of them, 39 participants, were based in France, while the others were spread across nine additional countries. Together, they were responsible for no fewer than 4,548 observations in various spectral lines, including Hα, Hα 2cb, Ca II H (H3), Ca H1v, Ca II K (K3), and Ca K1v.

Thanks to the strong commitment of the amateur community, there was only a single day in 2025 without an Hα observation, namely 22 December. For Ca II H and Ca II K observations, however, the number of days without data remains significantly higher, highlighting the importance of further expanding the observing network.

Within this international collaboration, I am currently still the only Belgian amateur actively submitting images to the Meudon Observatory. In total, I submitted 82 observations in 2025, placing me seventh among the most active amateur contributors. For the specific Ca II H and Ca II K lines, I rank fourth and fifth respectively. This clearly demonstrates not only the value of individual dedication, but also the crucial role amateur astronomers play in achieving long-term, continuous solar monitoring.

Sun May 2025 Sphere Synoptic - Inti Partner and Naming _YYYY-MM-DDTHH-MM-SS

I installed the new verion 1.2 of Inti Partner which has a tab Synoptic. It's possible to create a mp4 or GIF file made from solex images over multiple days. The end result is a simulation of the sun's rotation. I had some issues with the error "Date Error" but this is now fixed:

1) only use PNG/fits/ files

2) make sure the Log file is available at the same or upper map

or 

1) if you don't have the Log file, change the naming of the file to following format:

_YYYY-MM-DDTHH-MM-SS_  

2) be aware to change timing to UT time

I used files from May 2025: May 30, 19, 14, 11 and May 2nd. The synoptic maps identified 21 active regions from AR 4070 till AR4103

AR 4070 lat=-12.0° lonCarr=10.0°
AR 4072 lat=-19.0° lonCarr=325.0°
AR 4076 lat=5.0° lonCarr=305.0°
AR 4079 lat=8.0° lonCarr=244.0°
AR 4081 lat=7.0° lonCarr=213.0°
AR 4082 lat=-9.0° lonCarr=188.0°
AR 4084 lat=-21.0° lonCarr=129.0°
AR 4085 lat=3.0° lonCarr=139.0°
AR 4086 lat=7.0° lonCarr=207.0°
AR 4087 lat=15.0° lonCarr=57.0°
AR 4089 lat=17.0° lonCarr=28.0°
AR 4090 lat=-13.0° lonCarr=20.0°
AR 4091 lat=-13.0° lonCarr=33.0°
AR 4092 lat=-13.0° lonCarr=337.0°
AR 4094 lat=20.0° lonCarr=332.0°
AR 4096 lat=6.0° lonCarr=306.0°
AR 4099 lat=-13.0° lonCarr=255.0°
AR 4100 lat=8.0° lonCarr=243.0°
AR 4101 lat=3.0° lonCarr=259.0°
AR 4102 lat=-22.0° lonCarr=297.0°
AR 4103 lat=-17.0° lonCarr=287.0°

Sun January 4th

A 5cm layer of snow and a perfect blue sky. Sol'Ex time :)
My SSM3 Seeing monitor registrated very good seeing with levels below 1 arcs with sometimes below 0,5arcs. I still have issues with my allignment of the spectral lines which are curved. Maybe I need to adjust the slit? 

Setting: TLAPO80/480 with Sol'Ex by James R and ASI678MM

2nd Gen slit and Herschel Wedge

Tilt <0,5° and Sx/Sy 1,15

SSM3 seeing Monitor via SharpCap

Software: SharpCap, Inti, JSol'Ex, CS4, DeNoise AI

ROS 2026 - Registration is open

The next Solar Observers’ Meeting (ROS) is scheduled for June 13–14, 2026, in Serbannes. Once again, the program will feature many instruments dedicated to solar observation in white light, calcium lines, and the H-alpha line for observing prominences, as well as the latest filter innovations. The Sol’Ex spectrograph will also be part of the event.

Registration is now open.

Nikon D7500 Shutter Count

 

My Nikon D7500 has currently 42472 clicks. According to Nikon, my camera can reach 150.000 clicks.

The count was made using  https://www.camerashuttercount.com/

Sun January 2nd

My first observation of the Sun this year.
Moderate conditions and settings of Sol'Ex not perfect, mainly the north side of the Sun.

Setting

Sol'Ex by James R, TLAPO80/480 with ASI678MM

Tilt < 0,1° Sx/Sy 1,04

2nd Gen slit and Herschel Wedge

Software: SharpCap, Inti, JSolex 4.4.2 and CS4

My picture of Comet C/2025 A6 Lemmon in Magazine Heelal

My image of Comet C/2025 A6 Lemmon is published in Magazine Heelal. This is my 35th contribution to this Astronomical magazine. 

 

Happy New Year 2026

 Happy Astronomical New Year 2026 with lots of clear skies.