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Sun 24th January- Hydrogen Alpha

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#1 wargrafix

wargrafix

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Posted 25 January 2021 - 08:24 AM

A recent post from Bob about the tuning trick wasn't a fluke. It worked perfectly. In fact getting critical focus took me longer than tuning. I am trying my best and I hope my recent work shows I am making progress.

I brought out my 3x teleconverter and that thing is unstoppable!

 

 

ASI224MC

Solarmax 2 60mm

3X teleconverter

 

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Doing flats have been very, very difficult. I would do it, but no correction would be made.


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#2 MalVeauX

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Posted 25 January 2021 - 08:31 AM

Nice to see the tuning method worked well!

 

For your flat, since your FOV is filled by the disc, orient your FOV near the area you're about to image, but filled by the disc so that there's no edge in the FOV, then defocus until the features are gone. Fill your histogram to 67~72% or so. Create the flat frame (FireCapture) out of any number of frames (if super noisy, use more frames to stack out noise from your flat). Then re-focus after the flat is applied. Now slew over to the feature you're going to image without moving the camera at all and change exposure to whatever it takes to fill histogram to the same 67~72% (or the range you chose before). The exposures need to be similar so that the flat works.

 

Lastly, maybe try to use a 2x teleconverter. Your SM60II is generating a F6.6 focal ratio. The HA 656nm wavelength will critically sample on your 224MC's 3.75um pixels at F14. Your 3x teleconverter is significantly over-sampling this wavelength at F20. So drop down to a 2x for F13, which is as close to critical sampling as you can get for this combination at this wavelength. While imaging, capture in 8bit mono/RAW.

 

Very best,



#3 wargrafix

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Posted 25 January 2021 - 08:40 AM

I will retry the next time with defocusing. I know the 224MC is my weakpoint, but Its doing better than I thought it would.

 

With 2X I was getting most of the disk but the 3x gave good results. I have to retry and see which one give the best final image. I love my 2x and 3x teleconverter and my seeing handles both well. 

 

Your advice is most welcomed and I will continue to strive! Everyone really helped me get along really quickly


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#4 rigel123

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Posted 25 January 2021 - 09:00 AM

Marty gives good advice, good luck with your journey in this fun hobby!



#5 wargrafix

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Posted 25 January 2021 - 09:20 AM

Thank you! I love to test my equipment to the edge and pull back if need be. Anyone who seen my Lunar and planetary knows this. Solar is a different kettle of fish, but it is really fun. White light is easy mode, Halpha is master level.


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