Adding Ha to LRGB in AstroArt 6 for M101

[Craig123]

Hi all

I've had a look round to see how this is done but have not come up with an answer yet. Could anyone advise how i would add Ha to an LRGB image of M101 using astroart.Would it be best to add it to the completed LRGB image or start again with stacking and add it in at this stage.I haven't worked out how to blend layers in photoshop yet so just been using AA for now (the colour never comes through when i put it in luminosity mode in Photoshop) Ive attatched the image so far (first proper try at a DSO)...thanks to everyone who has helped me out on here >any pointers on how to improve this also greatly appreciated

Many thanks 

Craig

 

[DaveS]

You could put the Ha subs into the Red stack, but the last time I added Ha to a LRGB image I aligned it with the Red stack and used Add Image in the Arithmetic section. BTW, I'm still on AA5 as I've been too mean to update.

You'll probably see the image go white, but that's just an effect of the view range.

I then used the Red+Ha as the Red channel in Trichromy.

The only processing I do before combining the colours is Gradient Removal > Adaptive Divide. Then crop out any alignment edges and do another Gradient Removal > Adaptive Subtract.

Only then do I proceed to stretching, DDP etc.

But that's just my methodology, better ones may be available, YMMV, etc.

[carastro]

I think you need to add the Ha data to the red channel.  This will be another new learning curve for you but it is done in channels and layers in photoshop.  

In channels on the RGB image click on the arrow on the right and choose split channels, and this will split the colours into R,G B.

Then paste the Ha on top of the Red image.  Then go into layers with this Red/Ha image and select blend mode (from drop down menu in layers) to Lighten.  Flatten the image (another drop down men where the horizontal lines are).  

Then you need to re-combine the channels, so go back to the channels menu and select merge channels, then then choose RGB, makes sure you have the correct filters selected in R,G,B & click OK.  

Carole 

[Craig123]

Thanks Dave.That sounds good to me.Im finding Astro Art 6 to be pretty good so far...no doubt I will want to look at other  techniques  when I get more familiar with processing images.

 

[Craig123]

26 minutes ago, carastro said:

I think you need to add the Ha data to the red channel.  This will be another new learning curve for you but it is done in channels and layers in photoshop.  

In channels on the RGB image click on the arrow on the right and choose split channels, and this will split the colours into R,G B.

Then paste the Ha on top of the Red image.  Then go into layers with this Red/Ha image and select blend mode (from drop down menu in layers) to Lighten.  Flatten the image (another drop down men where the horizontal lines are).  

Then you need to re-combine the channels, so go back to the channels menu and select merge channels, then then choose RGB, makes sure you have the correct filters selected in R,G,B & click OK.  

Carole 

Hi Carole.Thats very helpful ..i need to get back on photoshop and work the luminosity blending  technique out properly..as usual it seems there's plenty to keep me busy adding ha

[carastro]

There might be another way to make Ha highlights stand out, but am still struggling with this myself.

Carole 

[ollypenrice]

I would use the method suggested by Carole. Look through an Ha filter and you'll see a deep, rich magenta-red. This bears no resemblance to looking through a luminance filter, which is just going to look transparent. So you shouldn't, in my view, light up your image exclusively in deep red-magenta light because it's completely false to do so and anything outside the reds will be massively suppressed. If you use Ha as luminance this is exactly what you are doing.

If you add Ha to red in blend mode lighten you are adding it where it belongs - in red - and it will only be applied where it is brighter than the existing red channel. This means you can stretch the socks off it because noise in the darkest regions will be darker than those regions are in red, meaning that that part of the Ha won't be applied.

I know of no sensible way to add it in AA though I may be missing a trick.

Olly

[carastro]

Further to Olly's post, of course Olly agrees with what I said because he taught me this method in the first place, thanks Olly.

By the way guys, Olly and Craig in particular, I made myself a template last night using the Marker mode in Artemis, it was only because of reading you guys talking about it on a thread, that I knew about it.  Am going to resurrect the template this evening when I am hoping to get more data.

Carole 

[Craig123]

Thanks Carole and Olly

4 hours ago, ollypenrice said:

I would use the method suggested by Carole. Look through an Ha filter and you'll see a deep, rich magenta-red. This bears no resemblance to looking through a luminance filter, which is just going to look transparent. So you shouldn't, in my view, light up your image exclusively in deep red-magenta light because it's completely false to do so and anything outside the reds will be massively suppressed. If you use Ha as luminance this is exactly what you are doing.

If you add Ha to red in blend mode lighten you are adding it where it belongs - in red - and it will only be applied where it is brighter than the existing red channel. This means you can stretch the socks off it because noise in the darkest regions will be darker than those regions are in red, meaning that that part of the Ha won't be applied.

I know of no sensible way to add it in AA though I may be missing a trick.

Olly

Thanks Olly..fascinating stuff.I managed to get a few hours of Ha last night om M101 but i didn't find it easy.My Atik 314 is screwed via the reducer on to the end of the sykwatcher focusing tube and i struggled badly to frame the image as i had it last time.The power kept going off on the camera while i tried to get it right and it all felt a little insecure.There must be an easier way!

Im hoping AA ( or indeed photoshop ) will take what i got even though its not aligned with the first night subs and its still useable..the galaxy is centred just not the right way round.Argghhh

[Craig123]

3 hours ago, carastro said:

Further to Olly's post, of course Olly agrees with what I said because he taught me this method in the first place, thanks Olly.

By the way guys, Olly and Craig in particular, I made myself a template last night using the Marker mode in Artemis, it was only because of reading you guys talking about it on a thread, that I knew about it.  Am going to resurrect the template this evening when I am hoping to get more data.

Carole 

Thanks again Carole...last night was something of a disaster compared to the last session.I couldn't frame the target the right way and got it to a right muddle with the camera on the threads of the focusing tube.The first time a just screwed it on tight but couldn't do that this time without eveything being in the wrong place and then it kept switching off when i moved it.Maybe i will try again tonight...pls let me know how to import the template.I lost my M101 markers but had one for Bodes and couldn't get it to appear last night.

Craig

[carastro]

I haven't imported the markers as yet, planning to do so tonight, but am assuming I right click on a looped image (Maybe I have to click on the Marker icon first), and import the file.  Fingers crossed it will work and if it does I will be a happy bunny.

I am surprised your Atik314 power kept going off, I have the same camera and it doesn't happen to mine.  Are you sure it is the camera and not a connection problem?

As regards not having the target oriented the same, provided it's not flipped or way out the stacking software should handle it, but of course you are going to have to take a big crop to get rid of the overlaps.  I don't have one of those screw on focal reducers, but does the camera screw on as well, or it is a squeeze fit?

Carole 

 

 

[Freddie]

AA will align even if some images are flipped.

[Craig123]

Thanks Freddie...thats very good to hear

[ollypenrice]

3 hours ago, Freddie said:

AA will align even if some images are flipped.

Indeed, but change the default setting in 'Star alignment translation and rotation' to 180 degrees. Do this on both the preprocessing (page 2) and the Image-align-align all.

Olly