Using the spectroheliograph and the ~30nm wide sodium ERF filter, I imaged the Sun in the He I D3 spectral line. Recordings processed with JSol’Ex, and details enhanced by the script below. For the final images, about forty individual frames (reconstructed scans) were stacked.

Fun fact, the light triangle in the lower half of the image corresponds to a dark feature in the corona, as seen on the SDO AIA 211 image.

The following are the script’s output, the filenames reflect the variable names in the script.

2024.11.07. autostretch -142 80

2024.11.07. autostretch 0 00

2024.11.07. average

2024.11.07. delta2

2024.11.07. HeLogHeRaw

2024.11.07. HeLogRot

2024.11.07. HeLog

2024.11.07. HeMin

2024.11.07. HeMul

2024.11.07. HePrimeRFP3PlusLogSq

2024.11.07. HePrimeRFP3PlusLog

2024.11.07. HePrimeRotFinalPow1

2024.11.07. HePrimeRotFinalPow2

2024.11.07. HePrimeRotFinalPow3PlusLog

2024.11.07. HePrimeRotFinalPow3

2024.11.07. HePrimeRotP

2024.11.07. HePrimeRot

2024.11.07. HePrime

2024.11.07. HeRawRot

2024.11.07. HeRaw

2024.11.07. kontinuumLinearRotated

2024.11.07. kontinuum

2024.11.07. lineZeroBLRotSQ

2024.11.07. lineZeroBLRot

2024.11.07. lineZeroLRot

He_offset = -142.8
He_context = 1
He_step = 1

kontinuum_offset = He_offset + 9
kontinuum_context = 3
kontinuum_step = 1

kontL = kontinuum_offset - kontinuum_context
kontR = kontinuum_offset + kontinuum_context

HeL = He_offset - He_context
HeR = He_offset + He_context


lineZero = min(autocrop2(range(-1, 1)))
lineZeroB = fix_banding(lineZero, 100, 50)
lineZeroBL = linear_stretch(lineZeroB)
lineZeroL = linear_stretch(lineZero)
lineZeroBLSQ = linear_stretch(pow(lineZeroB, 2))

[outputs]

HeRaw = min(autocrop2(range(HeL,HeR,He_step)))
HeRawRot = rotate_rad(linear_stretch(HeRaw), angleP)
kontinuum = avg(autocrop2(range(kontL,kontR,kontinuum_step)))
kontinuumLinearRotated = rotate_rad(linear_stretch(kontinuum), angleP)
delta2 = fix_banding(HeRaw - kontinuum, 100, 50)
HeLog = linear_stretch(log(HeRaw, 2))
HeLogRot = rotate_rad(HeLog, angleP)
HeLogHeRaw = linear_stretch(pow(HeLog + HeRaw, 1.2))
HeMul = linear_stretch(HeLogHeRaw * delta2)
HeMin = min(HeLogHeRaw, HeMul)
HePrime = linear_stretch(HeLog + HeMin + linear_stretch(pow(HeMin,4)) + linear_stretch(pow(HeRaw,2)) + HeLogHeRaw)
HePrimeRot = rotate_rad(HePrime, angleP)
HePrimeRotP = linear_stretch(pow(HePrimeRot, 1.1))
HePrimeRotFinalPow1 = linear_stretch(avg(HePrimeRotP, HePrimeRot)) 
HePrimeRotFinalPow2 = linear_stretch(pow(avg(HePrimeRotP, HePrimeRot), 2))
HePrimeRotFinalPow3 = linear_stretch(pow(avg(HePrimeRotP, HePrimeRot), 3))
HePrimeRotFinalPow3PlusLog = linear_stretch(HeLogRot + HePrimeRotFinalPow3) 
HePrimeRFP3PlusLog = max(HePrimeRotFinalPow1, HePrimeRotFinalPow3PlusLog)

HePrimeRFP3PlusLogSq = linear_stretch(pow(HePrimeRFP3PlusLog, 1.4))

lineZeroLRot = rotate_rad(lineZeroL, angleP)
lineZeroBLRot = rotate_rad(lineZeroBL, angleP)
lineZeroBLRotSQ = rotate_rad(lineZeroBLSQ, angleP)

And a quicky poem in Hungarian, because reasons

Hélium szkenneléskor
(partinagylajos és a többiek után szabadon)


A hélium, ha napkorong,
Felszín és légkör egyben.
Fény helyett fakón borong,
Hímzés halotti leplen.

A hélium a második,
Mutatja, hogy van első.
Mengyelejevtől Fermiig
Huszonhatfokú lépcső.

A hélium csillaghamu,
Főági füst pöfékje,
Majd héjanász, vörös vaku,
S a fehér törpe éje.