Spectroheliograms from the 25th Nov 22

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Alun_H
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Spectroheliograms from the 25th Nov 22

Post by Alun_H »

Clear sky most of the day yesterday (Fri 25th) allowed me to play with the 72ED and Sol'Ex in the CaK,Hydrogen alpha and Ha continuum,even caught a plane transiting the sun in one of the Ha scans. Used 16x slew speed on the EQ6 Pro to force the scans and the images are stacks of nine for the calcium K line (9 out of 9) and ten for both Ha (10 out of 14) and Ha continuum (10 out of 10). Ver 3.7 for reconstruction,Autostakkert and Astrosurface along with Photoshop CS2 for the usual stacking and processing.

Alun

CaK_221125.jpg
CaK_221125.jpg (109.93 KiB) Viewed 1180 times
Ha_221125.jpg
Ha_221125.jpg (241.4 KiB) Viewed 1180 times
Ha_221125_invert.jpg
Ha_221125_invert.jpg (254.25 KiB) Viewed 1180 times
Ha-continuum_221125.jpg
Ha-continuum_221125.jpg (272.45 KiB) Viewed 1180 times
sun-and-a-plane-221125.jpg
sun-and-a-plane-221125.jpg (239.5 KiB) Viewed 1180 times


Lunt 50THa solar scope
Lunt CaK B12 module
SW Evostar 72ED for full disk imaging
Sol'Ex SHG
80mm f/7 achromat used with pressure tune module off the Lunt with Lunt 100mm ERF
Bresser 90 f/10 achromat used for CaK & white light imaging & PST mod with Lunt 100mm ERF
Coronado SM40 (pre Meade) and BF10 filter set + SMII 60 richview DS etalon
Skywatcher EQ6 Pro and Ioptron CEM60
Then there is all the night kit which is far too long a list to write up here! :lol:
More images on view on my Flickr page...https://www.flickr.com/photos/alun_h/
thesmiths
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Re: Spectroheliograms from the 25th Nov 22

Post by thesmiths »

Those are all really good, especially the H-alpha. The Ca-K is, I think, too high contrast. Did it get that way in processing, or is that how the reconstruction software did it? I find with the Calcium lines, I need to be very careful not to overexpose because there is naturally very high contrast features and the bright areas can get saturated. I use the Photoshop feature "Lighten Shadows" and "Darken Highlights" to bring out the prominences.


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Re: Spectroheliograms from the 25th Nov 22

Post by marktownley »

Mazing disks there ALun!


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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!
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Re: Spectroheliograms from the 25th Nov 22

Post by Alun_H »

Thank you Douglas,Mark.

The CaK ended up like this in processing due to the exact scenario you described Douglas,I had overexposed on the line and resulted in not just the bright areas of the disk near on burning out but also had excessive light leakage in the background,hence the dark image.

Alun


Lunt 50THa solar scope
Lunt CaK B12 module
SW Evostar 72ED for full disk imaging
Sol'Ex SHG
80mm f/7 achromat used with pressure tune module off the Lunt with Lunt 100mm ERF
Bresser 90 f/10 achromat used for CaK & white light imaging & PST mod with Lunt 100mm ERF
Coronado SM40 (pre Meade) and BF10 filter set + SMII 60 richview DS etalon
Skywatcher EQ6 Pro and Ioptron CEM60
Then there is all the night kit which is far too long a list to write up here! :lol:
More images on view on my Flickr page...https://www.flickr.com/photos/alun_h/
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Re: Spectroheliograms from the 25th Nov 22

Post by Montana »

Wow!!! incredible shots! amazing to see a plane transit in a scan :hamster: :bow

I did prefer the imaging contrast of your earlier CaK pics though, this one is sadly too dark and loses some of the details, I hope you manage to sort out the exposure problems :)
Alexandra


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Re: Spectroheliograms from the 25th Nov 22

Post by thesmiths »

Alun_H wrote: Sun Nov 27, 2022 10:07 am I had overexposed on the line and resulted in not just the bright areas of the disk near on burning out but also had excessive light leakage in the background.
You mention "light leakage". This can be a real issue with the Solex design. As I understand it, some of the plastic components can be a bit transparent in the IR. I have seen several people put reflective tape over critical areas of the exterior. Also, the plastic is quite IR reflective on the inside. I know one person who has lined the inside with very light absorbent felt to eliminate reflections. The person also recommends putting some black matte tape on the edge of the grating that faces the collimator to reduce reflections off this edge. Particularly near 400nm where the light intensity is low, stray light can be quite harmful.


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Re: Spectroheliograms from the 25th Nov 22

Post by Alun_H »

Thank you Alexandra,I thought something had erupted on solar surface at first glance,but then realized it was a plane. Slew speed was just enough to freeze it.

I am going to look into light sealing the Sol'Ex better than it is,I already have the gold heat reflection cloth stuck to it but obviously there are a few areas still needing attention.

Alun


Lunt 50THa solar scope
Lunt CaK B12 module
SW Evostar 72ED for full disk imaging
Sol'Ex SHG
80mm f/7 achromat used with pressure tune module off the Lunt with Lunt 100mm ERF
Bresser 90 f/10 achromat used for CaK & white light imaging & PST mod with Lunt 100mm ERF
Coronado SM40 (pre Meade) and BF10 filter set + SMII 60 richview DS etalon
Skywatcher EQ6 Pro and Ioptron CEM60
Then there is all the night kit which is far too long a list to write up here! :lol:
More images on view on my Flickr page...https://www.flickr.com/photos/alun_h/
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Re: Spectroheliograms from the 25th Nov 22

Post by thesmiths »

See this image (on the left) posted by Jean-Francois Petitt https://groups.io/g/Solex-English/message/385. It demonstrates how reflective black PETG is compared to typical black surfaces used in optics.
Last edited by thesmiths on Tue Nov 29, 2022 10:25 pm, edited 2 times in total.


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Re: Spectroheliograms from the 25th Nov 22

Post by Alun_H »

Thank you for the link Douglas,I opened up my Sol'Ex (something I didn't do when I received it) and noticed how shiny the plastic actually is. I had some spare bits of black baize from when I flocked my SCT and Newtonian scopes and the interior is now much darker. The inside surfaces of the tubes holding the optics I will treat with a few strips of the Japanese Washi paper (matt black) which is perfect material for making anything light tight and non reflective.

Alun


Lunt 50THa solar scope
Lunt CaK B12 module
SW Evostar 72ED for full disk imaging
Sol'Ex SHG
80mm f/7 achromat used with pressure tune module off the Lunt with Lunt 100mm ERF
Bresser 90 f/10 achromat used for CaK & white light imaging & PST mod with Lunt 100mm ERF
Coronado SM40 (pre Meade) and BF10 filter set + SMII 60 richview DS etalon
Skywatcher EQ6 Pro and Ioptron CEM60
Then there is all the night kit which is far too long a list to write up here! :lol:
More images on view on my Flickr page...https://www.flickr.com/photos/alun_h/
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