The Sun on 2024-09-13, around the CaH line, also touching Hydrogen epsilon. Pixel shifts range from -36 pixels (blue wing) to +40 pixels (red wing), meaning somewhere around -2..+2 Å in total, give or take.
JSol’Ex stuff
Hydrogen Epsilon-Prime, extracted from the Epsilon-Raw and an adjacent context for continuum
Since Google is no longer our friend[1], thus finding the things we are looking for has become harder and harder[2], I decided to assemble a few things that help me tame JSol’Ex.
JSol’Ex Repo: https://github.com/melix/astro4j
JSol’Ex downloads: https://melix.github.io/astro4j/latest/en/jsolex.html
Help/Docs (at ImageMath): https://melix.github.io/astro4j/latest/fr/jsolex.html#imagemath
Extracting the Hydrogen Epsilon line, like it was He I D3, simple version (where, relative to CaH, epsilon is at +25px)
[outputs]
epsilon = min(range(23,27,1))
kontinuum2 = avg(range(14,18,1))
delta2 = fix_banding(epsilon – kontinuum2, 100, 50)
prime_stretched2 = linear_stretch(epsilon * delta2 + delta2)
prime_rot2 = rotate_rad(prime_stretched2, angleP)
A verbose and more complex version of the epsilon script:
The Sun in CaK, etalon+shg, on 2024-06-02
I combined some spectroheliograph data with the etalon, Sol’Ex at 62/400 with Lunt CaK B1800 at 102/1100.
The Sun in Helium I D3, spectroheliograph adventures
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.
The Spectral Composer
I’ve been photographing the Sun for more than two years now almost each and every day, in a bit of a hackish way: using all kinds of filters beyond the 540nm continuum – hydrogen alpha – near UV calcium triad. However, as I advanced, I discovered that this knowledge is simply not common in the community, and not just that, it’s also a bit hard to come by while googling around. Also, to better explain double stacking, off banding and similar stuff, articles like this one Altair Astro’s 3nm CaK Ultra filter: testing, comparison, review are maybe rare.
So I put together an interactive tool to play around with spectra, in a way amateur astronomers find it interesting. The Spectral Composer.
Altair Astro’s 3nm CaK Ultra filter: testing, comparison, review
Solar disk in Altair Astro’s 3nm CaK Ultra filter, enhanced contrast
I got a new filter to pudding-test: Altair Astro’s 3nm Calcium K Ultra, stated to have 3nm FWHM and a very high transmission. Let’s see how it performs.
Before we jump in, let me also present some information I compiled along the way, and some theory and links fellow amateur astronomers may find useful.
Important note: this article is not sponsored by the vendor, and the vendor has not influenced the conclusions presented below in any way.
Contents
- market overview: what’s available to amateurs, around the Calcium K line
- theory and practice: about the filters, the Sun and its spectrum
- first impressions, unboxing
- the tests themselves
- further (reference) images
- conclusions
The Sun on 2024-01-05
With a front ERF, Altair Astro’s Triband, 115mm, Tecnosky 102/1100 refractor, Lunt’s CaK B1800 and the ASI 533MM camera, I obtained the following:
CaK, 2.4Å
CaK 2.4Å, colorized
With a Tecnosky 102/1100 refractor, Herschel prism, ND 0.96, a filterwheel and the ASI 533MM camera, I obtained the following:
Antlia 3nm hydrogen alpha. The disk is clearly continuum, but the prominences were obvious even on the live view
Altair Astro’s G-band filter, 2nm fwhm at around 430nm cwl
Calcium K Sun on 2023-12-31
Using a fairly new setup, as they were in the light train: Altair Astro Triband D-ERF 115mm, Tecnosky 102/1100 ED refractor, Lunt CaK B1800, ASI 533MM, along with my EQ3 with the home built controller, I captured the following frames.
full disk, linear light
full disk, paraboloid gamma curve
detail from the full disk
same, colorized
Donate Button
A while back, well, in 2017, a friend mentioned rather publicly that I should put a donate button onto my website. So I put one into the sidebar of the main page, and into the photo planner. However, the software (the photo planner for example) and content (astrophotos, webcomic etc) I publish, they all remain as they were: free to use (unless fine print blah-blah).
The Sun on 2023-08-05
Using the good old 150/750 tube, with a ND3.8 film in front, I obtained the following frames.
Antlia CaK 3nm:
For reference, a Lunt CaK image, colorized and mono
And the infrared cwl 850nm, fwhm 20nm filter showing the active regions
