Having laid the groundwork, here’s a stack of 18 individual spectroheliograms, with artefacts edited out, showing the iron signal.

Sol’Ex, JSol’Ex, Altair Astro Tri-RGB as full aperture ERF, 62/400 scope, EQ3 with rebuilt control, and solar autoguider.

I also included a He I D3, CaK and Ha image from the same session, two scans because of the incoming clouds.

iron, false color

(tovább…)

A stack of 34 scans, with the Sol’Ex setup, going into the ionized iron at 5018.45A wavelength.

(tovább…)

„For WILL and SHALL best fitteth Tamburlaine”
(Temur ~ iron)

2025-03-22, Fe II 501.845nm, a somewhat artistic rendition of the data

Abstract

I recorded full disc solar images, in the spectral line of ionized iron, Fe II at 5018.45A. Due to the bandwidth, He I at 5015.7A was also recorded. I used the Sol’Ex spectroheliograph, mounted on a 62/400 ED refractor, stepped down to 42-46mm, by using 2″ narrow band filters as full aperture energy rejection filters, with an ASI 678MM monochrome camera. I reconstructed and further processed the recordings with JSol’Ex and its ImageMath module, and showed the presence of prominences and filaments. Creating aesthetic, but still faithful to the data renditions was among the goals.

A hobby is a hobby

I decided, with some little help from professional literature[1][2], to go into a particular iron line. Not the Fe (c) (at 495.7 nm, given as Fe I), which is rather well observed[3], and looks like many other metal lines, but the one at 501.845 nm, a line of ionized iron, of Fe II. What’s particularly interesting and somewhat unexpected for me, the amateur playing around with my Sol’Ex instrument, running all kinds of ImageMath scripts in JSol’Ex, is that, in Fe II at 501.845 nm:

• The active regions are dark, just like in He I D3, and unlike in many metals, like Ca in the G band at 430nm
• Faint proms are visible, and with math applied, filaments are also showing up
• Some brighter-than-its-medium areas are also visible, flares maybe
• Unlike with both the Mg and Na of the Fraunhofer lines, this line is relatively easy to extract and reconstruct with much less instrument/recording/processing artefacts, like the dreaded „polar caps”. Present, but much less.

Having explored many exotic lines, like

• the „high hydrogens” from epsilon (raw and „prime”) to „theta” if there is such a thing,
• the blue Helium at 447.15, and
• recently the UV Magnesium,

I needed a new challenge, and this iron line showed up on my radar.

(tovább…)

I had this old snapshot of the UV spectrum, and it took me to look into the literature to find out what I see. Well, Magnezium, among others. Because H alpha is such a low hanging fruit, and the Mg b triplet is so over-represented. Let’s boldly go where no amateur (that I know of) has gone before. The UV Mg.

So let us dive into those lines, with our friend, the Sol’Ex, and especially the 383.83nm Mg I — see the monograph.

Looking at the Hydrogen eta and the math versions, it is obvious that the prom at around 8 o’clock is in fact a filament reaching beyond, filaprom if you will. Another filament is also visible on the magnesium disk.

(tovább…)

It was almost unusually calm up there, so decent atmospheric seeing. 65 scans entered this stack: a spectroheliogram of the Sun with enhanced He I D3 details. Also, it has become fairly trivial to see the coronal features’ being reflected in the helium image, the holes at 9 o’clock and 2 o’clock, showing up as excess light in Helium, are rather obvious.

With the usual setup, from the Ersatz-Obsi, I imaged the Sun in He I D3. A stack of 96 spectroheliograms (scans).

Again, the coronal hole, as a large scale feature, is readily visible.

Processing scripts are here.

2025-02-09, the Sun in He I D3, enhanced signal

colorized

comparison with the SDO/AIA image