North American Nebula HaRGB

[Rodd]

My first attempt at the NA Neb.  This is as wide as I can get: TV np101is with .8x reducer.

[Davey-T]

Hi Rodd, would be really good if you could put a bit more detail in your post ie: filters sub times etc, still not sure about the colour cast you're getting in your images.

Dave

[Rodd]

All subs 20 minutes only 2 of each as this was done waiting for the heart to cross meridian so I would not have to do a Meridian flip, and Cygnus was hitting the trees anyway (R-2x20, G-2x20, B-2x20, Ha-2x20) at delta-45C, filters are Baader.  Master dark (10 20 minute frames).  No flats or biases.  

[Rodd]

Hi Dave--figured out how to change my signature info--this may help.

[Rodd]

Here it is.  

[Rodd]

I did not know it would retroactively put it in all my posts--sorry

[Davey-T]

I did not know it would retroactively put it in all my posts--sorry

Yes, it does that, if you put a picture in your sig and then change it, it changes it in all previous posts.

Dave

[Rodd]

Yes, it does that, if you put a picture in your sig and then change it, it changes it in all previous posts.

Dave

I think the master dark really did a good job canceling noise-this pic is minimally processed.  Aligned, stacked, tweeked a bit--but this is from before I started using FITs saves only and the initial combined stack did not need much stretching at all.    So allot of problems probably are connected to that issue that has been rectified.  I don't think the subs are worth reprocessing--only got 80 min total.  I am considering starting a folder for a DSO where I take several 20 min subs each night over the course of a year--of 2.  Actually I am thinking of starting 5-6 folders, 1 for each DSO ensuring that at least 1 of the targets is always in teh sky.  That way I can build up a huge exposure time for each one--200-300 hours.  Calibration may be a bit of a cluster though.

[laudropb]

Very nice image. Thanks for posting.

[ollypenrice]

The image has lots of potential but you have a huge colour gradient top to bottom (green top, red bottom.) Various software routines could tame this. The best is DBE in Pixinsight but there is also Gradient Xterminator. You'd be amazed by what they could do for you.

Olly

[davew]

Hi Rodd,

Just to add to the others, the image is coming on a treat. Just start throwing a lot more time at each object.

One thing that stands out for me is the heavy clipping both left and right. Left by far the worst. There's loads of dust detail you're throwing away. I realise it may be because you feel there aren't enough subs but try and get out of the habit 

Dave.

[Davey-T]

The image has lots of potential but you have a huge colour gradient top to bottom (green top, red bottom.) Various software routines could tame this. The best is DBE in Pixinsight but there is also Gradient Xterminator. You'd be amazed by what they could do for you.

Olly

This seems to be a feature of all your images Rodd and probably be worth trying to find the cause unless it's just local light pollution.

Dave

[Rodd]

This seems to be a feature of all your images Rodd and probably be worth trying to find the cause unless it's just local light pollution.

Dave

The image has lots of potential but you have a huge colour gradient top to bottom (green top, red bottom.) Various software routines could tame this. The best is DBE in Pixinsight but there is also Gradient Xterminator. You'd be amazed by what they could do for you.

Olly

Thanks guys--there is light pollution hear--maybe 20 min subs are too long.  I think the moon was bright during this session to.  Maybe my camera is not flush to the scope? Maybe flats will help?  I would like to identify the reason for it and fix it rather than rely of software to fix it. But, sometimes I look at a pic and say "wow--its pretty amazing we can do this--take pictures that are far better than what was in encyclopedias when I was a kid dreaming of astrophotography.  --even the bad shots are cool.    I think I will get the full version of Pixinsight tomorrow--I have the 3 tutorial videos so I might as well give it a proper go.  As far as clipping--I don't really know what I am doing--just trial and error--see if this looks good, see if that looks good--especially when I processed this image all of 2 weeks ago.  I assume by clipping you mean stretching so that the histogram gets truncated on left or right?  In Nebulosity there are 3 sliders to use and its a balance between the 3 and I really don't know what each one officially does beyond making the image lighter, darker or more contrasty.  I'm beginning to get a better understanding.  I am attracted to the empirical scientific approach of PixinSight--but the learning curve is downright frightening.  I'm going to do it though--a step a day will add up before to long (patience is not one of my stronger suits).  I really appreciate all the help and support.

[davew]

I did mean the histogram gets truncated, yes.

Dave.

[Pompey Monkey]

Thanks guys--there is light pollution hear--maybe 20 min subs are too long.  I think the moon was bright during this session to.  Maybe my camera is not flush to the scope? Maybe flats will help?  I would like to identify the reason for it and fix it rather than rely of software to fix it. But, sometimes I look at a pic and say "wow--its pretty amazing we can do this--take pictures that are far better than what was in encyclopedias when I was a kid dreaming of astrophotography.  --even the bad shots are cool.    I think I will get the full version of Pixinsight tomorrow--I have the 3 tutorial videos so I might as well give it a proper go.  As far as clipping--I don't really know what I am doing--just trial and error--see if this looks good, see if that looks good--especially when I processed this image all of 2 weeks ago.  I assume by clipping you mean stretching so that the histogram gets truncated on left or right?  In Nebulosity there are 3 sliders to use and its a balance between the 3 and I really don't know what each one officially does beyond making the image lighter, darker or more contrasty.  I'm beginning to get a better understanding.  I am attracted to the empirical scientific approach of PixinSight--but the learning curve is downright frightening.  I'm going to do it though--a step a day will add up before to long (patience is not one of my stronger suits).  I really appreciate all the help and support.

It is very daunting, but understanding will come in time.

You may fare better than me, but I find some of the tutorials have more than I can absorb in one go. I much prefer to get to grips with one tool at a time. 

[Rodd]

It is very daunting, but understanding will come in time.

You may fare better than me, but I find some of the tutorials have more than I can absorb in one go. I much prefer to get to grips with one tool at a time. 

Yes indeed--but my impatience doesn't let me do that .  I am still in the stage of-"lets push this button and see what it does".  It can be really frustrating, because on the off chance that I do come out with a "better" pic, I often do not remember the hyper convoluted path that lead me there.

[Davey-T]

I haven't used pixinsight but it will have some way of measuring pixel values so you can check for clipping.

Dave