03Jun2014 PZ's SHG Images: He D3
- p_zetner
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03Jun2014 PZ's SHG Images: He D3
A favourite wavelength: the He D3 Fraunhofer line. Lots of black plage evident.
I didn't "pretty up" this image as much in order to show the bright He D3 limb.
The comparison image is a He 1083nm image from the ChroTel telescope.
Cheers.
Peter.
He D3:
He 1083nm (ChroTel):
I didn't "pretty up" this image as much in order to show the bright He D3 limb.
The comparison image is a He 1083nm image from the ChroTel telescope.
Cheers.
Peter.
He D3:
He 1083nm (ChroTel):
Last edited by p_zetner on Thu Jun 05, 2014 11:06 pm, edited 1 time in total.
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Re: 03Jun2014 PZ's SHG Images: He D3
Excellent! How narrow is this line?
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Re: 03Jun2014 PZ's SHG Images: He D3
Cheers, Mark.
The author of the reference below gives a so-called "1/e width" of 0.4 Angstroms for the measured (Gaussian) absorption line profile in plages.
If you look at figure 2 of the reference, this amounts to a 0.6 Angstrom fwhm.
Reference:
Title: A measurement of the helium D3 profile with a birefringent filter
Authors: Labonte, B. J.
Journal: Solar Physics, vol. 53, Aug. 1977, p. 369-374.
Peter.
BTW: Daystar makes He D3 line filters at the low price of $12000 for a 0.4A (fwhm) bandpass and $15500 for the 0.3A bandpass (QPE) versions!
The author of the reference below gives a so-called "1/e width" of 0.4 Angstroms for the measured (Gaussian) absorption line profile in plages.
If you look at figure 2 of the reference, this amounts to a 0.6 Angstrom fwhm.
Reference:
Title: A measurement of the helium D3 profile with a birefringent filter
Authors: Labonte, B. J.
Journal: Solar Physics, vol. 53, Aug. 1977, p. 369-374.
Peter.
BTW: Daystar makes He D3 line filters at the low price of $12000 for a 0.4A (fwhm) bandpass and $15500 for the 0.3A bandpass (QPE) versions!
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Re: 03Jun2014 PZ's SHG Images: He D3
Hi Peter
interesting that He D3 line
interesting that He D3 line
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Re: 03Jun2014 PZ's SHG Images: He D3
probably one day for me......
One question : how do you manage the setup of your grating?
One question : how do you manage the setup of your grating?
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Re: 03Jun2014 PZ's SHG Images: He D3
Very nice and very interesting Peter!
Do you know why we have the H3 limb is so brightening?
Do you know why we have the H3 limb is so brightening?
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Re: 03Jun2014 PZ's SHG Images: He D3
Thanks, Wah!
Did you use your technique of producing a flat from a crop and dividing?
I notice you use "divide" blending mode in Photoshop. I don't have this mode !?!
Trying it in ImageJ usually doesn't work well, so I use a horizontal lines suppression in ImageJ FFT bandpass filter.
Peter.
Did you use your technique of producing a flat from a crop and dividing?
I notice you use "divide" blending mode in Photoshop. I don't have this mode !?!
Trying it in ImageJ usually doesn't work well, so I use a horizontal lines suppression in ImageJ FFT bandpass filter.
Peter.
Re: 03Jun2014 PZ's SHG Images: He D3
Ok Peter, Im impressed. I really like this line too! One day I would like to build a high res spectrograph that can take such images. For now, my spectrograph is 2A resolution with the 2400 grating, and between the 300 grating, and the two others I have Im working now on getting spectra of more solar system objects - mainly comets with my 12 inch. However, I do have just enough res you think to try some calcium drift scans? What would a 2A Cak drift scan look like? Can you take one for me so I can see if its worth it or do I have to build a new spectrograph?
Once again, your shots have always inspired me to look more deeply into the subject of spectrohelio graphs, and seems like I learn something every time I open Kens book!
Spectra of Comet ISON with spectrograph:
http://www.schursastrophotography.com/i ... F-1290.jpg
Once again, your shots have always inspired me to look more deeply into the subject of spectrohelio graphs, and seems like I learn something every time I open Kens book!
Spectra of Comet ISON with spectrograph:
http://www.schursastrophotography.com/i ... F-1290.jpg
Chris Schur
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Birch Mesa Observatory, Payson Arizona
Clear Creek Canyon Observatory, Happy Jack, Arizona
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Birch Mesa Observatory, Payson Arizona
Clear Creek Canyon Observatory, Happy Jack, Arizona
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Re: 03Jun2014 PZ's SHG Images: He D3
Thanks, Chris.
With a 2400 /mm grating, you should be able to improve your resolution by a factor of 10, or more. Bandpass is dependent on line density of the grating, the slit size and the collimator focal length. The (reciprocal) dispersion (A per um or A per pixel) will depend on these factors and the camera lens focal length. The bandpass I get with such a grating is better than 0.2A, closer to 0.15A (25um slit, 500mmfl collimator lens). The reciprocal dispersion I get (270mmfl camera lens) is about 0.06A per pixel (4.5um px).
Here's a pic of CaK with a simulated bandpass of about 2A. It's pretty contrasty, but you will have more fun with a narrower bandpass.
Cheers.
Peter.
With a 2400 /mm grating, you should be able to improve your resolution by a factor of 10, or more. Bandpass is dependent on line density of the grating, the slit size and the collimator focal length. The (reciprocal) dispersion (A per um or A per pixel) will depend on these factors and the camera lens focal length. The bandpass I get with such a grating is better than 0.2A, closer to 0.15A (25um slit, 500mmfl collimator lens). The reciprocal dispersion I get (270mmfl camera lens) is about 0.06A per pixel (4.5um px).
Here's a pic of CaK with a simulated bandpass of about 2A. It's pretty contrasty, but you will have more fun with a narrower bandpass.
Cheers.
Peter.
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Re: 03Jun2014 PZ's SHG Images: He D3
Chris,
Narrower slit gap and longer focal length lenses is the way to get an improvement....check out the options with SimSpecV4.
Narrower slit gap and longer focal length lenses is the way to get an improvement....check out the options with SimSpecV4.
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