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.

MoonSwatch - Omega Speedmaster Mission to Earthphase Moonshine Gold

Not only I was interesested in the Speedmaster as a Moonwactch but also the fact the MoonSwatch shows the phases of the Moon. And in the case of the MoonSwatch Mission to Earthphase, the watch shows aswell the phase ot the Earth from the Moon. At the 10 o’clock position, the earth phase indicator shows the Earth with oceans that glow blue under UV light. Beneath the earth phase indicator is an illustration of Snoopy and Woodstock on the Moon, marveling at the enchanting spectacle of Earth. The illustration showcases a phrase that appears only under UV light. At the 2 o’clock subdial, is a moon phase indicator with two radiant full moons, both coated with OMEGA’s Moonshine™ Gold. One of the moons is designed in the distinctive style of the world of Snoopy, while the other features a unique snowflake design. The design is unique for every model, ensuring that, just like snowflakes in nature, no two timepieces are ever the same.

I bought the watch last week in Brussels, together with my daughter.

Differential velocity - H-beta - JSolex

 

Differential Velocity of the Sun - JSolex 4.5 release

With the release of JSolex 4.5, it's now possible to calculate the differential velocity of the sun's disk using doppler effect of H-alpha.

I used some of my better Sol'Ex images and the result is very good compared with the theoretical one.

Rework Barnard's Loop Sh2-278

 

Reworking of the Barnard's Loop following protocol:
* Stacking using APP (H-alpha with Sigma 24mm f/1.8 & Optolong L-Pro Nikkor 23mm f/3.5)
* DeNoise AI

* Layer adjust using CS4

* Starnet ++ and adjusting using CS4

* Combining all in CS4

Barnard's Loop SH2-278

 

I used my new (second hand) Sigma 18-35mm f/1.8 lens for the first time. It was foreseen with a dew heater as ambient temperature was about -5°C.

Objective was capturing Barnard's loop with H-alpha filter and ASI2600MC.

This was my 6th session so far of which one failed. 

Polar allignment failed with SharpCap, so no polarallignment was done. With a 300s exposure time, the scope was pretty well alligned :)

Setting:

ASI2600MC with Signma 18-35mm f/1.8 and H-alpha filter (12nm)

Software: SharpCap, APP, CS4 and DeNoise AI

Stacking:

* Session 4: Nikkor 10-24mm f/3.8 H-alpha 23x300s

* Session 5: Nikkor 10-24mm f/3.8 Optolong L-Pro 6x300s

* Session 6: Sigma 18-35mm f/1.8 H-alpha 24x300s

Barnard's Loop or Sh 2-276) is an emisson nebula in Orion. It is part of the Orion molucelar cloud complex which also contains the Orion Nebula and Horsehead. The stars within the Orion Nebula are believed to be responsible for ionizing the loop.

The Barnard's Loop is about 1,400 ly away and 360 ly long. The loop is the result of a supernova about 2 million years ago.

Visit China - Nanchang and Beijing

The cosmology of imperial China is written into the geometry of the Forbidden City, where architecture functioned as a model of the universe. Aligned precisely along a north–south axis, the palace mirrored the celestial meridian, placing the emperor symbolically at the pivot between Heaven and Earth.
At its southern entrance, the Meridian Gate marked both political and astronomical orientation, acting as the terrestrial counterpart to the sky’s central meridian.

Sunrise between Bejing and Nanchang

Bayi Square Nanchang - Second largest square in China

Tengwang Pavilion Nanchang - One of the three famous historical towers

Skyline in Nanchang

Skyline in Nanchang

Temple of Heaven: Imperial Vault

Forbidden City Meridian Gate

Forbidden City Gate of Supreme Harmony

Court rituals timed to solstices and equinoxes reinforced this alignment, embedding governance within celestial cycles.
Beyond the palace, the ritual landscape extended to the Imperial Vault of Heaven, whose circular form echoed the dome of the sky and housed tablets of divine order.
This structure formed part of the wider Temple of Heaven system, where emperors performed sacrifices to maintain cosmic harmony.
To complete the celestial triad, annex shrines honored solar and lunar forces: the Temple of the Sun (incliuding planets and even the stars of the big dipper) in the east and the Temple of the Moon in the west.
Together, these sites formed a sacred map of the heavens projected onto Beijing’s ground plan.
The emperor’s authority thus depended not only on governance but on precise astronomical alignment with cosmic order.

Forbidden City Sundials

Wanshun Pavilion in Jingshan Parc