Paschen Gamma (enhanced) Solar Disk

Using the purpose built spectroheliograph, with stacked filters of 1075nm/50nm and 1100nm/50nm, I observed the Paschen gamma line (λ 10938.1Å), hoping to extract Hydrogen-resembling disk details. Neither the seeing, nor the low winter Sun helped the observation, worsening the already challenging endeavor.  For this observation, I used the IMX 585MM camera, instead of the 678MM, hoping to get more photons per pixel, sacrificing some spectral resolution — mixed results.

Still, the image published here, with the signal enhanced, could well be the very first Paschen Gamma Solar Disk, bringing the details to life.

The line itself is much weaker than the He I D3, it is a nebulous blur on the spectrum on the disk center, and is dwarfed by He I 10830 in the flash spectrum. In this respect, it resembles the situation of the (Balmer) epsilon line, which is overwhelmed by the calcium valley, or that of the He I D3 which is somewhat subtly visible while scanning, and is fully revealed only through continuum subtraction.

(tovább…)

With a rather unusual setup, the SolEx coupled with the IMX 571 wielding Altair Astro 26C camera, I observed a bright solar flare at 2025-09-28 08:43Z (a longer time series actually) at to my surprise, the helium line also lit up. This is not a typical nor a recommended setup of the SolEx. I sacrificed spatial (either way, bad seeing) and spectral (…) resolution for bit depth.

With the Helium image, I cheated a bit: the perpetually changing thin clouds resulted in the helium wavelength’s disk center getting saturated from time to time, so data’s been taken from non-saturated takes, to fill that gap.

He I 5015, continuum-subtracted

Fe II 5018, CLAHE-enhanced signal

spectra, before and during

The He I 5015 prominence, probably the least significant bit in the data

Using the usual setup, an ML Astro SHG 700 on a 80/540 refractor and a cooled IMX 678 camera, with an in-cone interference filter as an ERF, letting through the oxygen line, and coincidentally, the Fe II 5018.45Å and also the He I 5015.7Å lines, I managed, for the first time, to dig out a bright-ish prom in the green (turquoise-something) Helium line.

This could well be among the first, if not the very first amateur observation of this line.

See

https://physics.nist.gov/PhysRefData/Handbook/Tables/heliumtable2.htm

Processed using JSolEx.

(tovább…)

I stacked together some decent scans into this frame of hydrogen gamma. ML Astro SHG 700, with a 80/540 refractor, in-cone ERF, Ersatz-Obsi.

I imaged two helium suns, at 5875.6Å the good old He I D3, together with another He I at 7065.2Å. In the D3, the signal is both stronger and of shorter wavelength, and also not at the very extreme of what the device can do, so there are more details.

He I at 7065.2Å

He I D3