Omega Swan WIP - Pseudo RGB

[MarsG76]

Hello Astronomers,

This is a work in progress, I'm spending my clear moonless nights capturing narrowband data of M17, at 2032mm focal length through my 8" SCT, using my Cooled and modded 40D.

I still have SII to capture to complete the project but for now I played with the data I already have.

As it turns out that both the HAlpha and OIII subs have a considerable amount of blue data in them, separated due to the DSLR being a OSC camera, so I used the red out of the HAlpha image, green from OIII green channel and added the blue from HAlpha (the Hbeta data) and blue from the OIII stack and used it as the blue channel, resulting in a almost natural color pseudo RGB image, attached.

Once I have the SII data, I'll assemble the channels into a SHO narrowband image of M17.

Clear skies,

MG

 

 

Edited August 5, 2019 by MarsG76

[Adreneline]

I really like this image, especially the colours, but I'm not sure I follow the channel composition.

Am I correct in assuming this is R-G-B : Ha-HaO-HaO and if that is the case what are the proportions of Ha and O in the G and B channels. Or have I got it completely wrong. Sorry if I'm being a bit dim.

Thanks for sharing.

Adrian

[MarsG76]

1 hour ago, Adreneline said:

I really like this image, especially the colours, but I'm not sure I follow the channel composition.

Am I correct in assuming this is R-G-B : Ha-HaO-HaO and if that is the case what are the proportions of Ha and O in the G and B channels. Or have I got it completely wrong. Sorry if I'm being a bit dim.

Thanks for sharing.

Adrian

Since I captured the subs through filters using a OSC or color camera, the hydrogen alpha subs had the strongest signal in the red channel and a different signal in the blue, I'm assuming that it's hbeta...

Likewise OIII had the strongest signal in green with a bit of data in the blue channel, so I took the HAlpha stack red channel as RED and OIII green channel as GREEN but added the blue channels in both as BLUE in RGB.

The separation of hbeta is a benefit of using a color sensor for narrowband, where as a mono sensor would mix all signal as greyscale.

[Adreneline]

8 hours ago, MarsG76 said:

Since I captured the subs through filters using a OSC or color camera

Thank you - I was being dim - probably because it was late when I read your post.

Thank you for taking the time to explain what you have done - again! 😳

I really like the image.

Adrian

[Rodd]

Nice--I have had some interesting results using off filter combinations for various colors.  It opens up teh opportunities when you only have 2 filters worth of data.  there are a lot of details in this image.

Rodd

[MarsG76]

9 hours ago, Rodd said:

Nice--I have had some interesting results using off filter combinations for various colors.  It opens up teh opportunities when you only have 2 filters worth of data.  there are a lot of details in this image.

Rodd

Two filters but still three distinct channels of data without having to reuse any data to make a extra channel.

[MarsG76]

Slight processing tweak to bring out some of the fainter nebulosity.

 

[Rodd]

2 hours ago, MarsG76 said:

Two filters but still three distinct channels of data without having to reuse any data to make a extra channel.

Not sure what you mean. How could you not reuse data to make third channel?

Rodd

[MarsG76]

1 hour ago, Rodd said:

Not sure what you mean. How could you not reuse data to make third channel?

Rodd

Because when capturing narrowband HII and OIII using a color sensor, there is signal in the blue channel (probably HBeta) as well as red for HII and green for OIII captures...

Only using ONLY the red channel from HII as red and ONLY the green channel from OIII subs, than separating the blue channel from both HII and OIII and adding them together creates a third channel with data that is not used in the red (HII) and green (OIII) channels.

 

[Rodd]

5 hours ago, MarsG76 said:

Because when capturing narrowband HII and OIII using a color sensor, there is signal in the blue channel (probably HBeta) as well as red for HII and green for OIII captures...

Only using ONLY the red channel from HII as red and ONLY the green channel from OIII subs, than separating the blue channel from both HII and OIII and adding them together creates a third channel with data that is not used in the red (HII) and green (OIII) channels.

 

Did the 2 stacks look different?  It would be interesting to see

Rodd