The Sun in Helium D3, He I D3

This really feels like standing on the shoulders of giants. I got my Sol’Ex spectroheliograph, and started using it with INTI and JSol’Ex (links below). Long story short, while the Sol’Ex in the plastic feels like a toy, it bends, sags and kinks and twists and vibrates and all, I find it an excellent introduction, and beyond, to solargraphy and spectroscopy. The software? It blows my mind.

What I wanted to do here: get a Helium Sun similar to what I am familiar with in Hydrogen, meaning: we have a disk, we have prominences, we have plages in some way. What the programs I tried default to is a mathematical interpretation and data visualization that is far from „what we’d see in a scope”. Nota bene, we’d see nothing as even 0.5Å is too narrow a band to encompass a full disk, due to the issue of the angle of incidence, as far as interference filters go like those in Lunt solar scopes.

I use a 62/400 scope stepped down to whatever the aperture of 2″ filters is, as I use such filters as ERFs to keep the full spectrum out. The camera is a modified (cooled) ASI 678MM. I use the 2″ triband filter from Antlia for Ha and CaK and CaH, a somewhat lame Baader Hydrogen Beta 5.5 nm (I laughed when I saw its spectrum), Chinese Sodium filter in this case for the Helium D3 line, Chinese Magnesium-ish filter, and then broader band blue and red filters to look around exotic lines, like the Helium’s 447.15nm I caught a prominence in.

Self, with the instrument. The T-shirt is thematic, albeit the music is also good. I called the scope piglet a few times, for it has a filter drawer in front, taking 2″ filters as ERFs

The spectral line in the flash spectrum (beyond the limb of the Sun, it is the chromosphere here, plus whatever other light comes and scatters from the sky, but not the solar disk ie photosphere itself). On the left, that is a prominence in He I D3

Spectral lines marked, with the photosphere saturating the middle of the image

The Sodium D autostretch from JSol’Ex

The Iron line at -106 pixels

The Helium D3 line at -250 pixels. This is only the line’s reconstruction, no math applied

Sodium -35 pixels

A traditional Helium rendering, now automatic in JSol’Ex

I needed to write and then rewrite the mount drive and the accompanying software pack that I put together since the balcony and then the ersatz obsi are my launchpads towards infinity, but that’s life.

Sol’Ex: https://www.shelyak.com/produit/kit-optique-solex/?lang=en
JSol’Ex: https://github.com/melix/astro4j
INTI: http://valerie.desnoux.free.fr/inti/

My spectral composer: //csillagtura.ro/the-spectral-composer/

Some science: https://www.diva-portal.org/smash/get/diva2:1295682/FULLTEXT01.pdf