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What I meant to say in my previous post is that the Sun crossed the optical axis of the telescope in a line from the 2 o'clock to 8 o'clock position. Anyway, here's one more, H-beta reprocessed:
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I've added a processing routine to constrain the shape to a disc in a lossless manner, only geometry is affected. The sharply defined limb at 2 and 8 o'clock is due to it passing through the centre of the telescope objective during the capture sequence. The limb at 5 o'clock confirms a spectroscope/camera alignment problem that I've noted before while using a test setup.
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Thanks all for the kind comments. @Merlin66: The wavelengths are 410.17 nm (H-delta), 434.05 nm (H-gamma) and 486.13 nm (H-beta). @vineyard: The images were captured with a spectroheliograph using the drift method. It takes about two minutes to perform a capture and as it was windy, movement of the instrument affected the shape. The limb of the Sun was also affected but the software routine that I use to address the effect of atmospheric seeing on the limb restored it. Still need to do a routine to constrain the shape to a disc.
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Here is a comparison with the Meudon spectroheliograph at Paris Observatory. I assume that the plage areas are not the result of overexposure and that a narrower bandwidth makes a difference there. Filaments are definitely very wispy now so no further attempts at reducing the bandwidth.
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I recently finished the construction of my latest camera and jumped at the opportunity that presented itself yesterday to try it out. The new camera with smaller pixels reduces the bandwidth to 0.01 (H-alpha) to 0.02 (Ca II K) Angstrom/pixel. Narrowing the bandwidth unfortunately results in fainter filaments and prominences. For the first time I made an attempt to process the prominences to see what I'm left with. Next time I'll overexpose the disc of the sun to see if I can improve the result. For now the camera is a keeper.
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24/9/2021: All wavelengths from session.
Icosahedron replied to Icosahedron's topic in Imaging - Solar
Not present in solar spectrum. Check Rowland's Preliminary Table of Solar Spectrum Wavelengths pages 79 and 234. -
24/9/2021: All wavelengths from session.
Icosahedron replied to Icosahedron's topic in Imaging - Solar
Hi Apollo, I'm about to construct a camera with smaller pixels and will attempt Ba again after that and solving the interference problem. No Hg lines present in the solar spectrum according to the reference I use. -
24/9/2021: All wavelengths from session.
Icosahedron replied to Icosahedron's topic in Imaging - Solar
Thanks Rusted. Yes, left-clicking three times on the image will take you to full resolution. -
H-eta: 383.54 nm Ca II: 393.37 nm Fe I: 404.58 nm Ca I: 422.67 nm Fe I: 438.36 nm H-beta: 486.13 nm Mg I: 518.36 nm Fe I: 558.68 nm Na I: 589.0 nm Ca I: 612.22 nm H-alpha: 656.28 nm These images are the first to be processed by a mainly automated process which is still a work in progress. The narrow lines of Fe I (558.68 nm) and Ca I (612.22 nm) expose electrical interference that needs to be addressed:
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24/9/2021: The three faces of hydrogen.
Icosahedron replied to Icosahedron's topic in Imaging - Solar