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don4l

SH2-240 in OIII (12h 45m)

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This data was never intended to be an image on its own, but it is unusual, so I thought that it might be worth posting  as is.

I collected an awful lot of data last year on this target, but I was never able to create a finished image.  The problem was that as soon as the OIII data was stretched, the stars had become huge.  I don't know how to make star masks etc, so I was going to try for more data this year with a different, more sensitive camera. 

Starnet+ has come storming to the rescue. 

This image is a two panel mosaic.  The OIII mosaic was fed into Starnet and the original smaller stars were then added back in a gimp layer set to lighten mode.

I thought that I would post this up so that people can see what OIII is available in this object.  There  is a lot more that cannot be seen in this, because it really made the image quite noisy.

Equipment:  STL6303e,  FSQ106 at F3.6, EQ6, Chroma 3nm OIII filter

Software:  CCDSoft, CCDStack, Gimp, Starnet+

Exposure: Top panel:  OIII 415m, Bottom Panel: 350m  Total 12h 45m;

Stars are Ha.G,B  (G and B about 5m each in each panel)

It isn't a pretty image but it's different and I hope that people find it interesting.

Click the image for full size.

OIIIwStars.jpg

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Looks great.. nice and delicate veil....

 

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Well done Don, it looks great and should stand up well to mixing with Ha.   I've experienced the same set of problems with 11 hrs with a 200mm lens at f2.8.  The OIII is incredibly faint and I found that I had to ditch 8 hours of subs because of a sky haze which wasn't even visible during the session.  My stack showed very little signal and it needed a starless image to pull it out.  Have you got a load of Ha?  I also found it a big challenge combining the 2 channels.  It was frustrating because some of the faint wisps of OIII are distinct from the Ha.  As you say, a decision has to be made between pulling out the maximum detail vs keeping things smooth.  I went for detail initially but will go back enjoy working on a redo.   

Good luck completing the project.

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41 minutes ago, MartinB said:

Well done Don, it looks great and should stand up well to mixing with Ha.   I've experienced the same set of problems with 11 hrs with a 200mm lens at f2.8.  The OIII is incredibly faint and I found that I had to ditch 8 hours of subs because of a sky haze which wasn't even visible during the session.  My stack showed very little signal and it needed a starless image to pull it out.  Have you got a load of Ha?  I also found it a big challenge combining the 2 channels.  It was frustrating because some of the faint wisps of OIII are distinct from the Ha.  As you say, a decision has to be made between pulling out the maximum detail vs keeping things smooth.  I went for detail initially but will go back enjoy working on a redo.   

Good luck completing the project.

Thank you.

 

Yes, I have a load of Ha, and it does look very promising.  I'm still struggling with the processing.  I only posted this version because it really surprised me when it appeared on the screen. 

Your comment about OIII and haze really resonates with me.  It's very frustrating to process a bunch of hard earned data only to discover the next morning that it is useless.

I'm going to carry on playing with the data that I already have before deciding if I need to gather any more.  I will try a bit more OIII to see if the new camera makes any difference, but I am not going to gather another 12 hours this year.  It would be nice to be able to show more of the OIII detail,  or even the faint OIII haze that surrounds the whole object.

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Wonderful image!  I too am working on this object - also called Simeis 147 and the Spaghetti Nebula.  I have decent Ha but no OIII as yet as I'm waiting for a clear night with little or no moon.  I have the equipment but need the weather and moon to cooperate!  135mm f2.5 very good lens (Asahi Super Takumar), Astrodon 3nm filters and ASI 1600MM-Cool camera on EQ8 mount.

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This is a rough combine with the Ha.  I've got a lot of work to do before I produce the final image.

 

sh240tmp.jpg

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Well that's looking fabulous Don.  You have combined the colours brilliantly by pulling back  the Ha to let the OIII through.  Really subtle and delicate.  The other thing you've managed to do is suppress the OIII haze over the bottom left of the image which is what I'm struggling with at the moment on my redo.  You say you are a long way from the final image but looking at it on my laptop I think you will literally end up chasing shadows.  The image you have here is outstanding.

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