Found the next challenge! CN wavelength
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Found the next challenge! CN wavelength
While researching on magnetometers (June 1972 issue of Sky&Telescope) I found the "Babinet compensator" they used cost thousands $$$$$$.
Andre Rondi has achieved creditable results with basic 1/4 wave plates on his SHG, which I'm sure cost MUCH less!!
http://www.astrosurf.com/rondi/obs/shg/ ... nglais.htm
What caught my eye was a SHG solar image taken in the light of the molecular Cyanogen.
This records in the photosphere/ chromosphere interface and to quote "A significant observational advance occurred when Sheeley discovered that a spectroheliogram taken in the head band of cyanogen (3883.4 A) mapped the (magnetic) fields just as well as a Zeeman picture. Only the polarity information was missing....(these) pictures could be made more rapidly than the Zeeman films, better resolution was achieved."
I haven't been able to find any other solar CN images...this one was taken 50 years ago (July 4, 1970) That's my next challenge!!!
Andre Rondi has achieved creditable results with basic 1/4 wave plates on his SHG, which I'm sure cost MUCH less!!
http://www.astrosurf.com/rondi/obs/shg/ ... nglais.htm
What caught my eye was a SHG solar image taken in the light of the molecular Cyanogen.
This records in the photosphere/ chromosphere interface and to quote "A significant observational advance occurred when Sheeley discovered that a spectroheliogram taken in the head band of cyanogen (3883.4 A) mapped the (magnetic) fields just as well as a Zeeman picture. Only the polarity information was missing....(these) pictures could be made more rapidly than the Zeeman films, better resolution was achieved."
I haven't been able to find any other solar CN images...this one was taken 50 years ago (July 4, 1970) That's my next challenge!!!
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.io/g/astronomicalspectroscopy
http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
https://groups.io/g/astronomicalspectroscopy
http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
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Re: Found the next challenge! CN wavelength
Looking forward to seeing the results Ken
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Re: Found the next challenge! CN wavelength
Always nice to have a challenge
It will be interesting to follow your progress.
Stu.
It will be interesting to follow your progress.
Stu.
H-alpha, WL and Ca II K imaging kit for various image scales.
Fluxgate Magnetometers (1s and 150s Cadence).
Radio meteor detector.
More images at http://www.flickr.com/photos/solarcarbon60/
Fluxgate Magnetometers (1s and 150s Cadence).
Radio meteor detector.
More images at http://www.flickr.com/photos/solarcarbon60/
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Re: Found the next challenge! CN wavelength
Managed to get a better image in Mg(b2) which allowed comparison with a Ca II K image and my latest challenge the CN molecular line "head" at 3883A.
It looks like the Mg is very close to white light (photosphere) then the CN and finally the CaK in the lower chromosphere.
Note the filaments in CaK (and the proms)
MiniSHG on the ED80. (Some artefacts to be fixed on the CN line - not an easy target.)
It looks like the Mg is very close to white light (photosphere) then the CN and finally the CaK in the lower chromosphere.
Note the filaments in CaK (and the proms)
MiniSHG on the ED80. (Some artefacts to be fixed on the CN line - not an easy target.)
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.io/g/astronomicalspectroscopy
http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
https://groups.io/g/astronomicalspectroscopy
http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
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Re: Found the next challenge! CN wavelength
That's really interesting. I have to admit it never occurred to me that molecular species would be present at the photo/chromo interface. But a quick google shows the CN heat of formation is about 101 kcal/mole, which (says google) equates to about 50000 K temperature. Great images!
Kevin
Kevin
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Re: Found the next challenge! CN wavelength
Interesting Ken and very nicely captured. CN looks similar to CaH and Mg,
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Re: Found the next challenge! CN wavelength
The professionals say the CN reflects the active magnetic regions and hence different from the other wavelengths.
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.io/g/astronomicalspectroscopy
http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
https://groups.io/g/astronomicalspectroscopy
http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
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Re: Found the next challenge! CN wavelength
Ken, here’s a link to an example CN image I took several years ago.
https://solarchatforum.com/viewtopic.php?t=18063
The CN band is useful in the same way a G-band (CH molecule) image is useful. High spatial resolution images in CN reveal chromospheric bright points which are visible with a factor of 3 more contrast than those same bright points in a G-band image. These bright points are associated with intense magnetic fields concentrated into small regions. The CN image at larger image scales reveals magnetic fields only in the sense that the solar faculae are visible with high contrast and the faculae are associated with fields. I wouldn’t really like to make the claim that a CN image is equivalent to an unpolarized magnetogram, unless you want to extend that claim to all images in which faculae are visible!
Cheers.
Peter
https://solarchatforum.com/viewtopic.php?t=18063
The CN band is useful in the same way a G-band (CH molecule) image is useful. High spatial resolution images in CN reveal chromospheric bright points which are visible with a factor of 3 more contrast than those same bright points in a G-band image. These bright points are associated with intense magnetic fields concentrated into small regions. The CN image at larger image scales reveals magnetic fields only in the sense that the solar faculae are visible with high contrast and the faculae are associated with fields. I wouldn’t really like to make the claim that a CN image is equivalent to an unpolarized magnetogram, unless you want to extend that claim to all images in which faculae are visible!
Cheers.
Peter
Last edited by p_zetner on Sat Jan 29, 2022 12:11 am, edited 1 time in total.
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Re: Found the next challenge! CN wavelength
Here’s a reference:
A&A 462, 1157-1163 (2007)
Narrow-band imaging in the CN band at 388.33 nm
H. Uitenbroek and A. Tritschler
https://www.aanda.org/articles/aa/abs/ ... 86-06.html
A&A 462, 1157-1163 (2007)
Narrow-band imaging in the CN band at 388.33 nm
H. Uitenbroek and A. Tritschler
https://www.aanda.org/articles/aa/abs/ ... 86-06.html
- Merlin66
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Re: Found the next challenge! CN wavelength
Peter,
Thanks for the additional references.
The use of an old Lyot filter shows similarities to the narrowband MiniSHG results.
Thanks for the additional references.
The use of an old Lyot filter shows similarities to the narrowband MiniSHG results.
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.io/g/astronomicalspectroscopy
http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
https://groups.io/g/astronomicalspectroscopy
http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
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Re: Found the next challenge! CN wavelength
Here are some additional references and another (not particularly great) CN image I took in 2017:
https://solarchatforum.com/viewtopic.php?f=8&t=23945
Comparison with Ca K shows the difference between photospheric and chromospheric features as well as the correlation in location of faculae (CN) with plage (Ca K). This is explored further in Paper 1 below.
References:
Paper 1.
Title: New Observations of Solar Magnetic and Brightness Fields
Authors: Sheeley, N. R., Jr. & Liu, S. Y.
Journal: Line Formation in the Presence of Magnetic Fields, Manuscripts presented at a conference held in Boulder, Colorado, 20 August - 2 September, 1971. Boulder, CO: National Center for Atmospheric Research, 1972., p.285
https://adsabs.harvard.edu/full/1972lfpm.conf..285S
Paper 2.
Title: The Evolution of the Photospheric Network
Authors: Sheeley, N. R., Jr.
Journal: Solar Physics, Volume 9, Issue 2, pp.347-357
https://adsabs.harvard.edu/full/1969SoPh....9..347S
Cheers.
Peter
https://solarchatforum.com/viewtopic.php?f=8&t=23945
Comparison with Ca K shows the difference between photospheric and chromospheric features as well as the correlation in location of faculae (CN) with plage (Ca K). This is explored further in Paper 1 below.
References:
Paper 1.
Title: New Observations of Solar Magnetic and Brightness Fields
Authors: Sheeley, N. R., Jr. & Liu, S. Y.
Journal: Line Formation in the Presence of Magnetic Fields, Manuscripts presented at a conference held in Boulder, Colorado, 20 August - 2 September, 1971. Boulder, CO: National Center for Atmospheric Research, 1972., p.285
https://adsabs.harvard.edu/full/1972lfpm.conf..285S
Paper 2.
Title: The Evolution of the Photospheric Network
Authors: Sheeley, N. R., Jr.
Journal: Solar Physics, Volume 9, Issue 2, pp.347-357
https://adsabs.harvard.edu/full/1969SoPh....9..347S
Cheers.
Peter
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Re: Found the next challenge! CN wavelength
Hello,
Sunrise balloon 1-meter solar telescope did a lot of imaging in near-UV including CN line.
https://www.mps.mpg.de/solar-physics/sunrise-telescope
Unfortunatly, the images they took are difficult to find. I found some in a PhD thesis by Tino Riethmüller, "Investigations of small-scale magnetic features on the solar surface".
Hinode satellite also took a lot of CN images.
As said by Peter, CN images are somewhat equivalent to G-band images, with more contrast, but with much worse seeing effect. Maybe I'll try someday with the 300 mm Newtonia. I am not very far from it with my 396-5 nm filter.
Sunrise balloon 1-meter solar telescope did a lot of imaging in near-UV including CN line.
https://www.mps.mpg.de/solar-physics/sunrise-telescope
Unfortunatly, the images they took are difficult to find. I found some in a PhD thesis by Tino Riethmüller, "Investigations of small-scale magnetic features on the solar surface".
Hinode satellite also took a lot of CN images.
As said by Peter, CN images are somewhat equivalent to G-band images, with more contrast, but with much worse seeing effect. Maybe I'll try someday with the 300 mm Newtonia. I am not very far from it with my 396-5 nm filter.
Christian Viladrich
Co-author of "Planetary Astronomy"
http://planetary-astronomy.com/
Editor of "Solar Astronomy"
http://www.astronomiesolaire.com/
Co-author of "Planetary Astronomy"
http://planetary-astronomy.com/
Editor of "Solar Astronomy"
http://www.astronomiesolaire.com/
- p_zetner
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Re: Found the next challenge! CN wavelength
Hi Christian.christian viladrich wrote: ↑Sat Jan 29, 2022 9:00 pm Maybe I'll try someday with the 300 mm Newtonia. I am not very far from it with my 396-5 nm filter.
You might be interested in the attached table comparing bright point contrast in G-Band and CN (band head) images for various filter bandpasses. It’s from the reference:
A&A 462, 1157-1163 (2007)
Narrow-band imaging in the CN band at 388.33 nm
H. Uitenbroek and A. Tritschler
(Link above.)
Cheers.
Peter
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Re: Found the next challenge! CN wavelength
Peter,
Thanks.
I'd already found the Sheeley references.
There are very few CN band images around for comparison.
Thanks.
I'd already found the Sheeley references.
There are very few CN band images around for comparison.
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.io/g/astronomicalspectroscopy
http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
https://groups.io/g/astronomicalspectroscopy
http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
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Re: Found the next challenge! CN wavelength
Thanks Peter. They give equivalent contrast between CN and G-band for 1 A filters. My filter is unfortunately closer to nm than A.p_zetner wrote: ↑Sat Jan 29, 2022 10:54 pm Hi Christian.
You might be interested in the attached table comparing bright point contrast in G-Band and CN (band head) images for various filter bandpasses. It’s from the reference:
A&A 462, 1157-1163 (2007)
Narrow-band imaging in the CN band at 388.33 nm
H. Uitenbroek and A. Tritschler
We need a Lyot filter there, or a spectrograph.
Cheers
Christian Viladrich
Co-author of "Planetary Astronomy"
http://planetary-astronomy.com/
Editor of "Solar Astronomy"
http://www.astronomiesolaire.com/
Co-author of "Planetary Astronomy"
http://planetary-astronomy.com/
Editor of "Solar Astronomy"
http://www.astronomiesolaire.com/
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Re: Found the next challenge! CN wavelength
Informative thread, thanks all!
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!