Sol'Ex observation March 29

Sol'Ex observations done with the following settnig:

- TS/TLAPO80/480, ASI678MM with 2nd Gen slit (but with dust!!!)

- Herschel wedge

- SSD 

- Software: SharpCap, Inti, JSolex, CS4 and DeNoise AI

- Tilt angle 0,15°

- Sx/Sy : 0,88 (H-alpha)

- SSM3 monitor avg 1,5arcs

Relative Prominency number Rpha = 10H + E = 10 * 10 +53 = 153

H-alpha activity - H-alfa number

In the period from August 2024 to March 2026, 52 H-alpha observations were carried out using a Sol’Ex spectroheliograph on a TLAPO60/360 and later a TLAPO80/480. Processing via INTI results in superior resolution, meaning the calculated prominence relative number (Rp = 10H + E) is systematically higher than the VdS reference. This is reflected in a k-value of 0.76 with a strong correlation (R2 = 0.88). Furthermore, the data confirm the time-lag effect of the chromosphere: the H-alpha prominence maximum occurs later than the sunspot maximum in the photosphere. This is logically explained by the fact that prominences are often residual phenomena of active regions that are already decaying underneath. The methodology used follows the standard from "Die Sonne beobachten" by Reinsch and Völker.

Determination of the H-alpha Relative Number for the solar limb (Rp or RHa)
The formula is defined as follows (1)

Rp or RHa = 10 H + E

With:
Rp or RHa: the H-alpha relative number
H (Herde): the number of activity centers on the solar limb
E (Einzelerscheinungen): the number of individual limb phenomena, individual phenomena such as separate prominences or limb flares.

(1) Die Sonne beobachten - Reinsch, Beck, Hilbrecht and Volker

Conclusion:
My observations follow those of VdS and Kanzelhohe.
My observations are systematically higher, which may indicate a difference in equipment resolution, cf. traditional H-alpha versus Sol’Ex.
The k-value is 0.76 with a reliability (R2) of 0.88.
Observations confirm the "time-lag" effect of the H-alpha maximum relative to the sunspot number. This is logically consistent, given that sunspots occur in the photosphere and prominences in the chromosphere.

Lecture by Steven Goderis on micrometeorites

Lecture by Professor Steven Goderis at the annual VVS meeting in Brussels (Grimbergen MIRA). 

Professor Steven Goderis and his research team at the Vrije Universiteit Brussel employ advanced geochemical techniques to unlock the secrets hidden within microscopic space dust recovered from both the Antarctic ice and ancient geological strata. 

By conducting precise measurements of oxygen isotopes and identifying specific minerals like chromium-rich spinels, they can accurately trace the origin of these particles back to different types of primitive asteroids. A crucial part of their work involves analyzing the concentration of these micrometeorites within different rock layers, as the fluctuating numbers of these cosmic grains provide a direct record of massive impact events in Earth’s past. These sedimentary archives allow scientists to reconstruct the flux of extraterrestrial matter over millions of years and understand how the chemical composition of our solar system has evolved. Beyond identifying their source, the team examines the chemical alteration of these particles to determine past CO2 levels and atmospheric conditions during their high-speed entry into our planet's orbit. Furthermore, studying the magnetic properties trapped within these tiny grains provides a rare glimpse into the strength and orientation of ancient magnetic fields that shaped the early solar system. By combining these diverse analytical approaches, Goderis continues to push the boundaries of planetary science, using the smallest particles to answer the biggest questions about our cosmic history.

Micrometeorites

Selfie with Steven Goderis and in the back my friend Jean-Marie :)

Lecture Code Rood by Toon Verlinden

Together with colleague Walter and Philip, I attended a lecture by Toon Verlinden of his book "Code Rood" or Code Red.

In the book Code Red, Toon Verlinden analyzes the vulnerability of our modern civilization by linking four catastrophic scenarios to their historical predecessors. He uses the 1815 eruption of Mount Tambora as a chilling example of a supervolcano; it caused a year without a summer and global famine at the time, reminding us of the fragility of our current food chain. Regarding the danger of asteroids, he points to the 1908 Tunguska explosion, where a relatively small fragment wiped out thousands of square kilometers of forest, to demonstrate why we are now developing missions like DART to prevent impacts with precision missiles.

Verlinden also warns of a repeat of the 1859 Carrington Event, a solar storm that merely caused telegraph lines to spark back then, but today would completely cripple our power grid and the internet. Finally, he draws lessons from the devastating 1918 Spanish Flu to emphasize the necessity of rapid vaccine development and global surveillance against new pandemics. By analyzing these destructive moments from the past, Verlinden shows that our modern technology is not only a source of vulnerability but also offers our only real chance to survive a subsequent global disaster.

I bough his book back in 2024 and beside signing my book, a selfie with author was made.

Near occultation of SAO77121 by the Moon on March 24, 2026

Last Monday (March 24), I was located just north of the graze line for the lunar occultation of star SAO77121. My colleague Bart from Helios had alerted us, allowing me to track the event. As Bart predicted, I was in the area where the star was not occulted. My colleague Lieven also observed the event; he was positioned just south of the graze line and saw the star narrowly escape occultation as well.

Timing UT21h34

Setting: Star Adventurer GTI with Nikon D7500 and 200mm lens

Conditions: Transparency good and Seeing moderate. 

Sunspot AR4392 March 22

 

Inverted image of H-alpha spectrum of the Sun from last Sunday March 22, 2026. Crop from AR4392.

Picture made using SolEx with ASI678MM on TLAPO80/480.

Halo 360°

Capturing a very bright 360° Halo around the Sun.

Coronal Hole and Sol'Ex images March 22

My Sol'Ex was used to capture the HeD3 line and after editing is was possible to bring forward the current coronal hole of the Sun. A comparison was made with SDO/AIA 211A and GOES19 195A. All in all it's not most beautiful picture but still I could capture the coronal hole. For sure I will try this again when a more deligned coronal hole shows up.

The day started with some bad seeing but during noon time seeing became better. I made time to adjust the Sol'Ex and was able to get sharp images in all captured wavelenghts.
Tilt was corrected with some very good results: 0,1° deviation... not bad at all. The most suffer from dust on the slit. Yesterday I did some cleaning, but not enough it seems. 

Sun March 21

The Sun this afternoon, observed with Sol'Ex in H-alpha and CaIIH.

CaIIH1v

Sun in CaIIH

My last So'Ex observation was on January 4th this year. So today it was some trial and error...

Sun today in CaIIH 

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

SharpCap, Inti, CS4, DeNoise AI

Space Weather and Avidos - VVS Sun Working Group

Last week, March 8th, I attended the Sun working group of the VVS. Beside giving a lecture on "how to observe the E-Corona using a Sol'Ex" an interesting lecture was provided by Jan Janssens of the SIDC (Royal Observatorium of Belgium) of space weather and the aurora of Jan 19, 2026.

Selfie with Jan Janssens of SIDC 

In his lecture he refers to radiation during spaceflights and shows a link to the website. I searched this website and it's an ESA website in Sweden. After registration I could simulate my exposure during my flight from Brussels/Beijing in Jan last month. This was about 30microSv. 

Normal natural exposure in Belgium is about 2,4mSv. When going through the details, CT en PET scans are responsible for 7mSv for CT and 4,5mSv for PET. I wasn't aware this was such high.

This is the link to Avidos

This is the link to the dashboard 

ATT-Essen - 50 days to go

50 days to go ... May 9th is the day for the ATT Essen, the ATT (Astronomie- und Techniktreff) is the biggest trade fair for amateur astronomers.

For more information see this link.

Drone DJI Neo 2

One of my objectives is to expand my photographic skills and in particular taking pictures from a different angle. How would a sunset or sunrise look like from an angle way above ground level? For this reason I bought a drone or UAS (Unmanned Aircraft System).

I bought a DJI Neo 2 drone; it's a beginners drone in the Open Class A1 and Cx label type C0.
The camera sensor specs :
    * Sensor: 1/2-inch CMOS
    * Effective Pixels: 12 MP
    * Lens: FOV 119.8°,
    * Aperture, 16.5mm equivalent focus 35mm
    * Video Resolution: 4K/60fps (up to 100fps), 2.7K (9:16)
    * Max Video Bitrate: 80 Mbps
    * ISO Range: 100-12800
    * Stabilization: 2-Axis Mechanical Gimbal + RockSteady EIS
    * Storage: 49 GB Internal

The drone is equipped with a LiDar (Light Deteection and Ranging) sensor which measures distance and detects obstacles.

As the drone is equiped with a camera, the drone is regsitrated. For Belgium no certification is needed but for some other countries it's mandatory eg. Spain. I downloaded the 101 page training and completed succesfully my exam. So I'm a certified A1-A3 UAS Pilot :)

250.000 Visitors on my Blog - Thank You

Today, my blog reached 250K visitors. Thanks for reading my blogposts.

Release of Solar book by Christian Buil and Valerie Desnoux

Christian Buil and Valerie Desnoux will publish shortly a book on how to observe the Sun with a spectroheliograph. 

Selfie with Valerie and Christian

 

Solar Observation Indices: White Light vs. H-alpha

 

I was inspired by the VVS Solar Working group organised last Sunday, March 8, 2026 on the determination of H-Alpha activity on the Sun using indices. Going through some of my books like "Die Sonne beobachten" from Beck and Völker (see aswell link to my books) and a couple of websites I made following list on potential use of H-alpha indices. I made a reference towards white light observation.

Corona

The corona is the outermost layer of the solar atmosphere, consisting of extremely tenuous and very hot plasma.

- Plasma: H⁺ and e⁻
- Follows magnetic structures
- Temperature anomaly:
        - Magnetic reconnection provides the basic heating

        - Alfvén waves (wave heating) transport energy further out into space
- Radiation spectrum: X-rays (RX), EUV, and white light due to electron scattering
- Density: ~10⁻¹² of the photosphere
- Charged particles escape from the corona and move through our solar system as the solar wind.

We can destiguish different regions:

E Corona (L Corona – Line Corona)
Emission from highly ionized metals (Fe XIV, Ni XII, Ni XIII, Ca XV).
Ionization occurs at t = 2 million K.

K Corona
Thomson scattering by high-energy electrons.
The scattering does not affect the wavelength itself, but the electrons’ velocities cause a Doppler effect, which smears out the wavelengths and thus forms a continuous spectrum (continuum).

F Corona
Caused by dust that scatters photospheric light.
No change to the spectrum shape, and it shows an absorption spectrum; hence the Fraunhofer-line spectrum.