M101 Red with Ha

[Rodd]

I finally have a chance to make a respectable M101--but it will be a long road, plenty of time for the sky gods to conspire against me.  This is an experiment.  I added Ha to the Red channel  to see if I could do it without having collected Blue and green.  It sounds foolish--of course it can be done.  But in PI extracting the red channel from an RGB linear image is such a crucial step to cleaning the Ha of red leakage, that I wasn't sure.  It seems to have worked.  But to tell the truth, the red filter picked up the Ha regions better than I expected. This image is a good example of my sky--5.6 hours of red , 7.5 hours of Ha and the faint extensions are still almost invisible.  Seems hopeless.

C11Edge with .7x reducer and ASI 1600.  170 120 sec red, 90 300 sec Ha.--about 13 hours.  Bin 2x2

 

 

[ollypenrice]

Setting aside the faint extensions, that is a contrasty and sharp image.  Since the faint extensions aren't red (or Ha) you can't expect to find them in this palette, surely?

There's no fine detail in the faint extensions, at least accessible to amateur telescopes, so I'd just throw everything you have at them and blend them with this.

Olly

[Rodd]

4 hours ago, ollypenrice said:

Setting aside the faint extensions, that is a contrasty and sharp image.  Since the faint extensions aren't red (or Ha) you can't expect to find them in this palette, surely?

There's no fine detail in the faint extensions, at least accessible to amateur telescopes, so I'd just throw everything you have at them and blend them with this.

Olly

Thanks Olly. That is good to know that there is very little red in the extensions.  Blue then?  Hopefully I get some good nights for luminance.   

[Rodd]

8 hours ago, ollypenrice said:

Setting aside the faint extensions, that is a contrasty and sharp image.  Since the faint extensions aren't red (or Ha) you can't expect to find them in this palette, surely?

There's no fine detail in the faint extensions, at least accessible to amateur telescopes, so I'd just throw everything you have at them and blend them with this.

Olly

Here is a much better processed image.  I always push too far

 

[ollypenrice]

8 hours ago, Rodd said:

Thanks Olly. That is good to know that there is very little red in the extensions.  Blue then?  Hopefully I get some good nights for luminance.   

I just split the channels on my own M101, which has strong outer extensions, and blue is the brightest, though they are present in all channels.

Olly

[Rodd]

5 hours ago, ollypenrice said:

I just split the channels on my own M101, which has strong outer extensions, and blue is the brightest, though they are present in all channels.

Olly

See, even red.  I wonder if collecting a huge amount of data will help, or are the extensions I below the sky fog threshold in my sky.  

[ollypenrice]

4 minutes ago, Rodd said:

See, even red.  I wonder if collecting a huge amount of data will help, or are the extensions I below the sky fog threshold in my sky.  

Is it the LP which makes you reluctant to use luminance?

Olly

[Rodd]

7 hours ago, ollypenrice said:

Is it the LP which makes you reluctant to use luminance?

Olly

I think so.  If I take a luminance sub that is longer then a certain limit for the system I am using, the unstretched histogram is way to the right and the frame is very light gray. The last time I tried with the C11 it was between 60 sec.