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Today's Great Prominences, and AR12704 | Quark | April 16th 2018

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#1 MalVeauX



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Posted 16 April 2018 - 10:40 AM



Really chilly this morning here in Florida, weird! In the 50's F, but sunny and clear skies, so I couldn't resist taking a look at the major prom developments and decaying arch prominences from the past few days. AR12704 is more active and has more interesting features and has appeared in white light (but barely visible). In HA, AR12704 has plenty of interesting activity around it though. I imaged both wavelengths to show the comparison. Seeing was poor, a solid 1 most of the time. It was difficult to even focus in white light, so I wasn't able to get critical focus for the white light sunspot and dumped most of that data. I only kept one sequence of the white light sunspot to show as a comparison to it's HA brother. That sunspot is just so tiny in white light. But it seems more active than it was a few days ago, so maybe there will be something to look forward to over the next 2~3 days while it's still facing us.


Celestron Omni XLT 120

Baader UV/IR Block Filter

Quark Chromosphere (Hydrogen Alpha)

ASI174MM Camera

Baader Solar Film (White Light)

Baader Solar Continuum (540nm) Filter (White Light)

Explore Scientific 3x Focal Extender (White Light)

Skybender with 393nm filters & KG3 filter (Calcium Light)

Orion Sirius
















Barely visible AR12704 in white light, compared to above's HA, so tiny.




The quiet disc in white light (532nm~540nm) & calcium/iron light (393nm):






Very best,

Edited by MalVeauX, 16 April 2018 - 01:33 PM.

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#2 Joe1950



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Posted 16 April 2018 - 11:29 AM


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#3 MalVeauX



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Posted 16 April 2018 - 01:40 PM

Some info one the 393nm setup. I used my 80mm F7.5 refractor for full disc because the FOV gives me the full disc. I did not use a white light filter at all, the aperture is open to the sun. Not recommended for anything other than imaging of course. To manage the heat, I use a KG3 IR absorption filter. Instead of blocking IR, it absorbs all IR, including the really long wavelengths that most IR cut filters do not reject. The filter radiates heat as it absorbs it to the surrounding air. It gets hot, but it keeps everything behind it safe. I use a Skybender, but really it's not needed, it just acts as a house to hold more filters. You can literally replace it with some extension tubes that thread on both sides to simply install more filters in sequence. The filter after the KG3 is a 370~395nm filter that is a short pass and keeps a narrow group of wavelengths passing through. Then, two 393nm filters are stacked on the camera's nose. Ultimately this is actually a few angstroms towards the blue side of things, more like Iron, but it looks a lot like Calcium does at 393nm, and is essentially still white light, but with a lot more surface contrast to see faculae and sunspot sites which are not present in true white light. These filters can be picked up at Semrock. I got the KG3 from Newport.












Here's how it looks real time in SharpCap when I was imaging, where you can plainly see more surface features at 393nm than in white light.




Comparison discs to show what the filtration does compared to white light:






Very best,

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#4 RickV


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Posted 16 April 2018 - 06:27 PM

Wow Marty, what a great set of posts! waytogo.gif 

You showed what you imaged and the gear you used to image with... what more can anyone ask? flowerred.gif

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#5 MathiasV



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Posted 16 April 2018 - 07:54 PM

Great shots! 

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#6 CHASLX200



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Posted 17 April 2018 - 05:58 PM

If i only had a simple cam to take pics.  I have very steady seeing and need to learn to take my first images.

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#7 rigel123



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Posted 17 April 2018 - 07:47 PM

Excellent shots Marty!

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#8 KarlL



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Posted 18 April 2018 - 09:29 PM

Marty -


Superb shots.

#9 nickatnight



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Posted 18 April 2018 - 09:33 PM

Dang. That's good stuff. waytogo.gif

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