Solex Processing HeID3 using INTI Software

While I previously relied on JSolex for spectroheliogram processing, I had not yet utilized Inti to process the neutral helium HeID3 spectral line. My motivation stems from the insights presented in Christian Buil and Valérie Desnoux’s book, Guide de l'observation solaire avec un spectrohéliographe. In particular, the potential of the HeID3 line to reveal low-contrast features such as coronal holes makes it a compelling target for high-resolution solar imaging. This post outlines a step-by-step workflow for processing HeID3 observations using Inti.

Version: Inti V7.0.3

After starting Inti, open the file and select "safe polynome coefficientt". Next run the proces by selecting Go! 

My ROI includes both the NaID2, FeI (5888,81) and HeID3 line. Inti uses the NaID2 line as reference. Christian mentiones that ROI with only FeI and HeID3 would be better.

Next, select Helium-Corona free page and mark "automatic polynome computation" and "Transversllium correction". The shift is currently not important and you can put in zero aswell. Offset 1 on -8 and Offset on 12. Run the process selecting Go!

Select Frame and Mean-Start. When doing this the shift from NaID2 to HeID3 will be calculated automatically. You can also select the line by clicking on the HeID3 line and pressing OK.  Next run the process by selecting Go!

Depending on the outcome, play around by changing the shift value by plus or minus 1 and find the most contrast image.

After editing in CS4, this is result... which also shows the coronal hole.