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Owl (M97) finished.

ollypenrice

By ollypenrice
in Imaging - Deep Sky

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ollypenrice

ollypenrice

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The first night's capture showed that OIII is the big player on this target, notably for the elusive outer shell. We could find no trace of any outlying Ha. The Ha component has a hard and sharp outer boundary ending well within the limits of the OIII. So last night we shot 12 x 15 minutes of OIII in Bin 2 to add to the 6x15 minutes of unbinned. Ha 9x15 minutes and 4 x 10 mins per colour. While I know that theory makes binning 4x as effective I remain highly doubtful about this in practice, especially if the intention is to resize it upwards to the unbinned scale in order to use it. However, the extra OIII made all the difference to the image which was captured and processed in the good company of guest Alex Potiatynyk. 

TEC140/Atik 460 mono/Mesu 200. I always enjoy Ha-OIII-RGB projects and this one was great fun.

5afed50041e59_M97OWLHaOIIIRGBcrop.thumb.jpg.575a92ae3b35831a6a78c9a34a8680c9.jpg

Olly

 

 

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ollypenrice

ollypenrice

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34 minutes ago, Rodd said:

Didn't even know that ring existed.  Nice.  (interior stars quite faint still)

Rodd

Many planetaries will have faint outer shells, I suspect. I think the interior stars just are quite faint. The central progenitor is mag 16, for instance. The stars outside the nebula have had some reduction, particularly the brightest ones. Those inside have had none. The interior stars' colour comes straight from the RGB, re-applied after the NB was added since it had affected their colour slightly. Bearing in mind your comment on version one, and agreeing with it, I have given the three central stars a slight sharpening to make them pop against the nebulosity. Normally I never sharpen stars.

1 hour ago, tooth_dr said:

Very nice Olly.  Do you think there would be any remote possibility of capturing Oiii using a DSLR and 12nm filter?

I have never imaged with a DSLR so I just don't know, but I seem to think I've seen OIII DSLR images posted. There are twice as many green filters as blue and red on the Bayer so maybe it would work. 

Olly

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ollypenrice

ollypenrice

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A few processing notes:

As usual I added the Ha to red in blend mode Lighten and called this Ha to Red.

To a copy of this I then added OIII to green and called it OIII to Green.

I then went back to a copy of Ha to red and added OIII to blue calling that (of course!) OIII to Blue.

I then stacked up the three as layers in PS with Ha to Red at the bottom, OIII to green in the middle and OIII to Blue on top. Remember that Ha is present in the red on all of these layers. This means that, with the final RGB image used as a reference on the screen, you can adjust the opacity of the top layer to replicate the original colour balance.

The last step was to apply the OIII as luminance in order to pull out the outer shell. It was applied only lightly (at low opacity) but did help the shell considerably.

Olly

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Petergoodhew

Petergoodhew

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4 hours ago, ollypenrice said:

A few processing notes:

As usual I added the Ha to red in blend mode Lighten and called this Ha to Red.

To a copy of this I then added OIII to green and called it OIII to Green.

I then went back to a copy of Ha to red and added OIII to blue calling that (of course!) OIII to Blue.

I then stacked up the three as layers in PS with Ha to Red at the bottom, OIII to green in the middle and OIII to Blue on top. Remember that Ha is present in the red on all of these layers. This means that, with the final RGB image used as a reference on the screen, you can adjust the opacity of the top layer to replicate the original colour balance.

The last step was to apply the OIII as luminance in order to pull out the outer shell. It was applied only lightly (at low opacity) but did help the shell considerably.

Olly

Thanks Olly - it's really useful to see how you achieve your magic!

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