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