PIER-14 Cloudless Andromeda

Hello Ray,

you have processed the data very nicely and naturally. I especially like that the core is not burned out. Something I unfortunately did not manage in my version.

CS
Darius

Hello Darius, 

Thank you for your kind comments. I must admit that I was pleased with the result I achieved with the Hydrogen data, that was until I saw your image. Maybe because I didn't stretch the data that much has made the core more discernible. 

Kind regards and CS, 

Ray 

That's very nice indeed Ray!

I have just started processing that data set today. I may ask your help on the Ha knots in the spiral arms. I neve seem to get that right :-(

That's very nice indeed Ray!

I have just started processing that data set today. I may ask your help on the Ha knots in the spiral arms. I neve seem to get that right :-(

There are several ways to combine LRGB data with Ha.
I have combined only the LRGB data in Pixinsight.
On the Ha channel I did a continium subtraction. Afterwards I stretched the Ha channel very much to make the faint clouds around Andromeda visible.
Finally, I blended the Ha channel over the LRGB image in Photoshop and did some post-processing on the overall image.

If you also want to strech your Ha channel very strongly, make sure that you put a mask over Andromeda to protect the bright regions.

I hope I could help you.

CS
Darius

There are several ways to combine LRGB data with Ha.
I have combined only the LRGB data in Pixinsight.
On the Ha channel I did a continium subtraction. Afterwards I stretched the Ha channel very much to make the faint clouds around Andromeda visible.
Finally, I blended the Ha channel over the LRGB image in Photoshop and did some post-processing on the overall image.

If you also want to strech your Ha channel very strongly, make sure that you put a mask over Andromeda to protect the bright regions.

I hope I could help you.

CS
Darius

Thanks for the advice Darius. I am not a Photoshop user, so I try to do everything in Pixinsight, although I do have access to Affinity for final tweaks.

Can I ask what you mean by 'continuum subtraction'? Is that the Adam Block method?

There are several ways to combine LRGB data with Ha.
I have combined only the LRGB data in Pixinsight.
On the Ha channel I did a continium subtraction. Afterwards I stretched the Ha channel very much to make the faint clouds around Andromeda visible.
Finally, I blended the Ha channel over the LRGB image in Photoshop and did some post-processing on the overall image.

If you also want to strech your Ha channel very strongly, make sure that you put a mask over Andromeda to protect the bright regions.

I hope I could help you.

CS
Darius

Thanks for the advice Darius. I am not a Photoshop user, so I try to do everything in Pixinsight, although I do have access to Affinity for final tweaks.

Can I ask what you mean by 'continuum subtraction'? Is that the Adam Block method?

 

Continium subtraction is a processing method in which the red channel is subtracted from the Ha channel. What remains is an image with a pure Ha signal. This method can be used to make weak Ha areas more visible. I recommend to remove the stars from the red channel and the Ha channel before the continuum subtraction. Otherwise you will get black dots on your Ha image. You can remove the stars with Starnet or StarXTerminator.

In this video you will see how to do a continuum subtraction in Pixinsight: https://youtu.be/k6yL93M-IUk

If you can understand German, I recommend this video: https://youtu.be/GqIqjMFlvp4

There the theory and practice is well explained.

CS

Darius

OK Everyone,

Here is the first process of this data that I am reasonably happy with.

I wanted to get the Ha knots clear first, so I have made no attempt to pull out the Ha 'clouds' around M31. I will try that next.

I also did not want to strongly emphasise the Ha knots. I wanted them to blend into the spiral arms (personal choice!).

Nothing great, but the first time I have successfully added Ha to an RGB image. So thanks for all the advice and links to tutorials. You have helped me make progress.

Nicely integrated Richard. Now you'll be able to experiment and enjoy reprocessing other galaxies where we have Ha data.