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M27 in Ha


Deneb
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Hi

I took the 120ED out last night with the 314L+ with the wind playing havoc. M27 captured in Ha using 8x600secs. Now can someone please tell me what those artifacts are across the image & how to get rid of them..

M27_Ha.jpg

I've noticed it on 4 of my fit files, but the rest are okay.

Nadeem.

Edited by Deneb
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very deep Nadeem, that outer shell is coming through well....those artifacts are hot pixels, did you do darks? if you did then your darks dont match the lights, you will find it difficult to remove them after stacking, you will make a much more tidy job removing them on the individual subs with a hot pixel filter

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I'm glad you got rid of those worms - This one looks much better...!

Would I be right in thinking that there's some OIII around M27 and if so, would an OIII filter pick up the outer shell any better...? (Or am I completely barking?!)

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It has so. That will teach me 'remember to take Darks'. But mind you, due to having set point cooling can I not take the darks now or does the scope have to be out as well?

Nadeem.

Edited by Deneb
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Nadeem, I get exactly the same "scratches" on my 314L+.

But.... the scratches always seem to be of a random nature, so darks dont always completely cure it. The best way I found is to use the kernel filter in maxim (hot pixel), then anything thats left over after processing gets cleaned up with PS.

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You can certainly take darks now and apply them which would give a better result than the noise reduction you applied in the second image. This also indicates that you have some differential flexure - join the club!!

I have messed about with hot pixel removal and darks and generally found that hot pixel removal is the most effective of the two with my very low noise Sony 285 sensor but stacking in SDMask mode is the best solution for me. In MaximDL I found that hot pixel removal could produce black spots - Nebulosity software seems to have a terrific hot pixel removal routine but sadly it destroys most of my MaximDL FITS header data!!

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mmm, still deciding Guy, but im steering toward some more Ha+O3 & RGB..

Nadeem.

Yeh why not, Ha& OII ... looking forward to seeing it, Moon on the way and nights getting lighter for another 4-5 weeks?

You seem to be settling in with the 314 :)

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