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Coronado PST Double Stack Imaging Help Please

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#1 Runcoach

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Posted 09 May 2021 - 08:24 AM

Hello,

 

I am a newbie at all of this with just enough knowledge to get into trouble. I have a Skywatcher HEQ5 Pro mount with a Coronado PST Double Stack and a QHY 5L-II-M.

 

I capture using FireCapture, convert the SER files from FireCapture to AVI using PIPP. I then stack the AVI into a tiff using AutoStackert and process it using Photoshop CC 2021.

 

I can't for the life of me get these wonderful images that you all get with the wonderful surface detail. Any help you can offer would be great. I have attached the last image I produced.

 

Its a little dark but I was trying to get the surface detail. Please be gentle with your feedback, I am new at this.

Attached Thumbnails

  • Sun_040921_700am.png

Edited by Runcoach, 09 May 2021 - 08:31 AM.


#2 MalVeauX

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Posted 09 May 2021 - 08:38 AM

Hi,

 

What does it look like single stacked?

 

What was your exposure/histogram?

 

You will need to share much more information to help diagnose this. Software for acquisition, parameters and histogram as a result, total imaging train configuration, screen shots of all of it if you can.

 

Right away it looks off-band completely, as there's no filaments/plage area around the spot, and there should be, so its more a photosphere view or far red/blue wing view of chromosphere. So without knowing anything, I would advise, get the primary etalon tuned on-band first (single stack). Then add the 2nd etalon and remove the ghost reflection (minimal tilt needed possible) and then tune it back on-band (tilt induces blue shift) by tuning towards red wing.

 

Very best,



#3 Runcoach

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Posted 09 May 2021 - 09:17 AM

Hello MalVeauX,

 

Single stacked it looks like the attached (I assume you mean straight out of AutoStackert and before Photoshop).

 

I used a gain of 1, an exposure of 5.0 ms, and the histogram was about 65% (no clipping).

 

Pardon my ignorance but you will have to explain "off-band". Oh, okay, I think I know what you mean.

 

I focused first single stacked, tuned the primary etalon or thought I did, added the secondary etalon, tweaked the focus, adjusted the tilt but found it got too dark so adjusted it back, then adjusted the secondary etalon and found it too dark so had it fully counter clockwise facing opening (my apologies for not knowing the whole red/blue thing).

 

I hope this makes sense. Thank you for your help.

Attached Thumbnails

  • Sun_071156_pipp_lapl5_ap12.png


#4 Tom M

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Posted 09 May 2021 - 09:28 AM

Using the PST double stacked you should be able to get decent images. Here's one I took prior to selling my PST & SM40 with just a quick pass through AS!3, ImPPG & PS. You should see something like this visually prior to setting up with the camera and then you will only need to adjust the focus and the levels, etc.

 

med_gallery_9290_3810_102923.jpg

 

If you are seeing the actual sunspots then, as mentioned, you are not very close to on band. I would leave my SM40 on but adjust both etalons until I got what I was looking for. It was usually an iterative process but only took a few seconds to get the desired results.


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#5 rigel123

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Posted 09 May 2021 - 09:33 AM

You can actually stack your SER files in Autostakkert without converting them to AVI,s unless you are using PIPP to simply pick the best frames for you to stack in AS!3.  As Marty states it appears that your scope is not tuned properly as it looks like a white light image as you can see the penumbra around the sunspots. 

 

What Marty meant by single stacked was with the scope without the 2nd etalon on the front of the scope.  I can see after stretching your image a bit what looks to be a "ghost" image of the sun in the lower left which is typical of a double stack arrangement.

 

You first want to tune your scope while looking through the eyepiece without that second etalon on the front.  You adjust it until you can see some detail on the surface.  Now is a good time as there are some filaments on the surface.  Once you see these at the highest contrast on the filaments then you can add the 2nd etalon to the front of the scope and you only need to adjust it so that the "ghost" image of the sun moves off of the main image.  This is short and sweet but the basics before adding your camera.

 

Solar-Disk-5-9-2021.jpg



#6 MalVeauX

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Posted 09 May 2021 - 09:35 AM

Hi,

 

So the primary problem is that you're not on-band. You will need to tune your etalon so that you see plage (bright white areas) and filaments (dark strands) around that active region and then you'll see chromosphere features. Right now, you're off band to the point where no chromosphere features are evident, so its more like a photosphere view and soft on focus (or seeing). Practice tuning it visually as a single stack. It will be very obvious on this AR when you're on band, the plages and filaments near it will be bright/dark respectively rather than absent.

 

Very best,



#7 Runcoach

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Posted 09 May 2021 - 09:42 AM

Thank you everyone for the feedback. Of course it is cloudy for the next few days. I will heed your advice and try again when it clears.


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